Protein hydrolysates are mixtures of free amino acids and short peptides produced by breaking down protein-rich raw materials, either chemically or with enzymes. In plant science they belong to a fast-growing class of products known as biostimulants: substances that, applied in small quantities, enhance crop performance without acting as conventional fertilizers, pesticides, or growth regulators. The mechanisms are thought to include a signaling role for specific amino acids, stimulation of root development, improved nutrient uptake, and priming of the plant’s antioxidant machinery. What distinguishes the new work is the raw material, fish waste from aquaculture, and the production route, enzymatic hydrolysis, which is gentler than acid hydrolysis and better at preserving bioactive peptides.

The research team prepared the hydrolysate from rainbow trout (Oncorhynchus mykiss) by-products using an enzymatic method and then tested it on tomatoes cultivated in a soilless greenhouse system. Soilless, or hydroponic, cultivation is prized for its water efficiency and precise control of the root zone, but it also deprives plants of the complex microbial and organic chemistry of living soil. Growers therefore compensate with carefully balanced nutrient solutions, and biostimulants have emerged as a possible third lever. The researchers applied the hydrolysate in two ways, to the roots and to the leaves, at four concentrations: zero as a control, 0.2 grams per liter, 0.4 grams per liter, and 0.8 grams per liter.

The dose mattered, and the pattern that emerged was far from a simple more-is-better relationship. Plants receiving the 0.2 grams per liter treatment posted the strongest photosynthetic performance, with a photosynthesis rate of 39.3 micromoles per square meter per second and stomatal conductance of 797.2 millimoles per square meter per second, alongside the highest chlorophyll content index and the greatest accumulation of mineral nutrients in plant tissue. Moderate stomatal opening with high chlorophyll is exactly the profile a grower wants: the leaves are pulling in carbon dioxide efficiently while retaining water, converting light into sugars at close to peak capacity.

At the 0.4 grams per liter dose, the plants’ stress physiology told a subtler story. Leaves showed the highest values for the antioxidant enzyme ascorbate peroxidase, at 50.4 millimoles, and for malondialdehyde, a marker of oxidative damage to cell membranes, at 0.010 nanomoles per gram, together with a proline concentration of 0.21 milligrams per gram. Proline is an osmoprotectant that cells accumulate under pressure, while malondialdehyde indicates lipid peroxidation, so its elevation suggests that this dose pushed the plants mildly out of their comfort zone even as it triggered a stronger defensive response. The antioxidant enzyme ascorbate peroxidase converts hydrogen peroxide, a reactive oxygen species, into water, and its induction is a classic sign of biostimulant priming, in which a mild challenge leaves the plant better prepared for stress.

The strongest yield and quality gains appeared at the highest dose tested. Plants treated with 0.8 grams per liter produced the heaviest average fruit weight, 114.3 grams per fruit, along with the highest leaf catalase activity, 0.71 units per gram per minute, and the highest lycopene value recorded in the trial, 34.4. Lycopene is the red carotenoid pigment prized both for its contribution to tomato color and for its documented health benefits as a dietary antioxidant, so elevating it is commercially and nutritionally significant. The authors concluded that yield and profitability were increased with hydrolysate doses of 0.4 and 0.2 grams per liter respectively, indicating that the economically optimal dose depends on whether a grower prioritizes total output or input efficiency.

Not every quality parameter moved in the same direction. The highest soluble solids content, 3.98 percent, and the highest anthocyanin concentration, 0.19 grams of cyanidin-3-glucoside equivalents per kilogram, were both found in the untreated control plants. This is a recurring phenomenon in horticulture: when plants are well supplied with water and nutrients, sugars and pigments get diluted in larger fruits, whereas slight stress concentrates flavor compounds. For growers the finding implies a genuine trade-off between size and taste chemistry, one that a carefully chosen dose of biostimulant may help navigate rather than eliminate.

The study’s framing of foliar application as a supporter of physiological homeostasis deserves attention. The authors suggest that spraying the hydrolysate onto leaves helps the plant maintain its internal balance under standard greenhouse conditions, essentially acting as a biochemical stabilizer rather than a dramatic growth driver. In a soilless system, where the root environment is already precisely controlled, foliar feeding of amino acids and peptides may smooth out the small daily fluctuations in water status and nutrient supply that plants would otherwise buffer themselves. This positions protein hydrolysates less as miracle inputs and more as a fine-tuning tool for high-technology growing systems.

The broader significance lies in the circular economy logic of the approach. Aquaculture is one of the fastest growing food industries in the world, and fish processing generates large volumes of protein-rich waste, including heads, skin, bones, and viscera, that often becomes low-value feed or landfill. Enzymatic hydrolysis converts this material into a product with clear agricultural value, closing a loop between marine food production and protected horticulture. Compared with synthetic plant growth regulators, hydrolysates are perceived as more sustainable and more acceptable to consumers, and compared with mineral fertilizers they require far smaller application rates because they work through biological signaling rather than bulk nutrient supply.

There are caveats, as with any single-crop, single-season greenhouse trial. The results were obtained in one soilless system with one hydrolysate preparation, and the interplay between application method, dose, and outcome is complex enough that recommendations for commercial growers will need replication across seasons, cultivars, and growing conditions. The biochemical markers measured, from malondialdehyde to catalase, indicate that the doses used were not physiologically inert and that the highest dose imposed some oxidative signaling. Still, the study provides a quantified, dose-resolved picture of how a waste-derived biostimulant moves the needle on tomato photosynthesis, fruit weight, and pigment content. As growers worldwide face pressure to cut synthetic inputs while raising yields on shrinking land and water budgets, the idea that tomorrow’s tomatoes could be fattened, in part, by yesterday’s fish fillets is exactly the kind of practical, evidence-based circularity that sustainable agriculture has been searching for.

Subject of Research: Use of fish-waste-derived protein hydrolysate as a biostimulant to improve tomato growth and productivity in soilless cultivation

Article Title: Utilization of protein hydrolysates to enhance growth and productivity of tomato under soilless cultivation systems

Article References: Tütüncü, A. Ç., Özer, H., Korkmaz, K., Hazneci, E., Öztürk, B., & Gülser, C. (2026). Utilization of protein hydrolysates to enhance growth and productivity of tomato under soilless cultivation systems. BMC Plant Biology. https://doi.org/10.1186/s12870-026-09959-9

Image Credits: AI Generated

DOI: 10.1186/s12870-026-09959-9

Keywords: protein hydrolysate, biostimulant, soilless cultivation, tomato, rainbow trout, circular economy, foliar application, lycopene, antioxidant enzymes, greenhouse horticulture, aquaculture waste, plant physiology

The choice of wheat as the experimental subject reflects both its global importance and its well-documented sensitivity to salinity during early development. Wheat is among the most widely cultivated cereals on Earth, and in many irrigated production systems—particularly in arid and semi-arid regions of Central and Western Asia, North Africa, and Australia—the water available to farmers carries substantial dissolved salt loads. Seedling establishment is a particularly vulnerable window, because young plants have limited root systems, thin cuticles, and immature antioxidant machinery. A seedling that survives early salt exposure with reduced vigor often carries that penalty through to tillering and grain fill, which is why interventions aimed specifically at the seedling stage can have disproportionate agronomic value even when the plants eventually recover.

The two cultivars examined in the study, Chamran and Mehregan, are bread wheat varieties bred for the contrasting but overlapping challenges of Iranian and regional production environments. Including two genotypes rather than one matters scientifically because salt responses in wheat are strongly genotype-dependent: varieties differ in their capacity to exclude sodium at the root, to compartmentalize it in vacuoles, and to maintain photosynthetic activity under osmotic strain. When a treatment effect appears in both cultivars, as the fresh-weight benefit of the combined formulation did at every salinity level tested, it suggests a mechanism that operates broadly rather than one contingent on a particular genetic background. At the same time, the magnitude of the benefit differed between the two lines, with Mehregan showing a larger relative gain at the highest salt concentration, a reminder that biostimulant performance cannot be assumed to transfer uniformly across germplasm.

The severity of the salt treatments deserves attention when interpreting the results. Irrigating with 150 millimolar sodium chloride already imposes stress well beyond what most productive wheat fields experience; 300 millimolar approaches the limits of what wheat seedlings can tolerate at all. These concentrations were chosen to create a steep stress gradient in which protective effects could be detected unambiguously, not to mimic field conditions directly. The fact that plant height, fresh weight, and dry weight all declined substantially at the highest concentration in both cultivars confirms that the stress was genuinely severe. Against that backdrop, even modest absolute differences in biomass between sprayed and unsprayed plants represent meaningful biological protection, and the roughly thirty-five percent fresh-weight advantage of the combined treatment over the unsprayed control in Chamran at 300 millimolar sodium chloride is notable.

Chitosan itself has a long history as a plant-protective agent, and its mechanism of action is worth unpacking. Derived by deacetylation of chitin from crustacean shells or fungal cell walls, chitosan is a positively charged polysaccharide that can interact with negatively charged components of plant cell surfaces. It is recognized by plants as a microbe-associated molecular pattern, triggering innate immune signaling pathways that overlap with those activated during abiotic stress. Spraying chitosan on leaves has been reported to induce stomatal closure, stimulate the phenylpropanoid pathway, and prime antioxidant enzymes, effects that collectively harden plants against subsequent stress. The polymer also forms films, which is why it is used commercially as an edible coating for fruit; on a leaf, that film-forming behavior may both retain moisture and slow the diffusion of dissolved solutes.

Selenium occupies an unusual position in plant biology. It is not considered an essential element for higher plants, yet at low concentrations it reliably alleviates oxidative stress in many species. The reason lies in its chemistry: selenite taken up by leaf tissue can be assimilated into selenocysteine and ultimately into selenium-containing forms that bolster the glutathione peroxidase system, an alternative route for decomposing lipid peroxides that complements the ascorbate-glutathione cycle. Selenium supplementation has also been shown to enhance the activity of catalase and superoxide dismutase and to slow chlorophyll degradation under stress. The dose window is narrow, however, because selenium becomes toxic to plants at concentrations only modestly above those that are beneficial, which makes delivery method and formulation critical variables in any field application.

The formulation strategy used in the study—ionotropic gelation with tripolyphosphate—is a standard technique for assembling chitosan into small cross-linked particles. When a tripolyphosphate solution is added to an acidic chitosan solution, the multivalent anion bridges the cationic polymer chains, condensing them into discrete nanoparticles. Incorporating sodium selenite into this process entraps or associates the selenium species within the particle matrix rather than leaving it as a free salt on the leaf surface. The practical rationale is that a particle-associated active ingredient may adhere better to the waxy cuticle, release its payload more gradually, and suffer less from rapid wash-off or photodegradation than a simple aqueous spray. The authors were careful, however, to note that the physicochemical properties of their specific formulation—particle size, surface charge, selenium loading efficiency, and release kinetics—were not characterized in this work, leaving an important gap between the concept and a fully validated delivery system.

The confocal microscopy experiment using fluorescein isothiocyanate-labeled chitosan provides some of the most visually direct evidence in the paper. Fluorescence was strongest in the epidermal layer and weaker in the underlying mesophyll, indicating that the polymer associates readily with the outer leaf tissues but penetrates only partially into the interior. This pattern is consistent with what is known about foliar uptake in general: the cuticle is a formidable hydrophobic barrier, and most solutes enter through stomata, trichomes, or specialized epidermal cells rather than diffusing across the cutin matrix. The authors are appropriately cautious in their interpretation, emphasizing that detecting the labeled chitosan demonstrates association with the leaf but does not prove that selenium, or the intact formulation, was internalized. Tracking the selenium itself would require a different analytical approach, such as isotope labeling or elemental imaging.

The gene expression data add a molecular dimension to the physiological observations. The genes examined span several functional categories that map directly onto the known components of salt stress. TaAPX and TaCAT encode ascorbate peroxidase and catalase, the two central enzymes of hydrogen peroxide detoxification. TaNHX1 encodes a vacuolar sodium-proton antiporter that sequesters sodium ions inside vacuoles, removing them from the cytoplasm where they would interfere with enzymatic function. TaHKT9-7D belongs to the high-affinity potassium transporter family, whose members participate in sodium retrieval and potassium-sodium balance in both roots and leaves. TaP5CS catalyzes the rate-limiting step in proline biosynthesis, and Ta4CL3-6B encodes a 4-coumarate ligase acting early in the phenylpropanoid pathway, which supplies lignin precursors and a wide range of protective secondary metabolites. TaPXPAO is involved in polyamine catabolism, a process that both generates hydrogen peroxide and participates in stress signaling.

The pattern of expression changes tells a coherent story. In unsprayed plants, salt exposure actually decreased the transcript levels of most of these genes, a somewhat counterintuitive result that may reflect stress-imposed suppression of transcription or a failure of the seedlings to mount a full defensive response at the severe concentrations used. The single gene that rose, TaP5CS, aligns with the accumulation of proline, the classic osmoprotectant whose synthesis plants upregulate under water stress. In contrast, the selenium-containing treatments at the highest salt level elevated TaCAT, TaNHX1, and Ta4CL3-6B in both cultivars, suggesting activation of antioxidant defense, sodium compartmentalization, and phenylpropanoid metabolism respectively. The combined formulation additionally influenced the polyamine catabolism gene, hinting at a broader reprogramming of stress metabolism when the two biostimulants act together.

The authors are explicit that these expression changes are correlative: no enzyme activities, metabolite quantities, or ion contents were measured to confirm that the transcriptional shifts translated into functional differences. This is a standard and honest limitation of RT-qPCR surveys, and it defines the agenda for follow-up work. Measuring catalase activity, tissue sodium and potassium concentrations, proline levels alongside TaP5CS expression, and phenylpropanoid end products would connect the molecular signals to the growth outcomes. Similarly, the weak correlation between growth traits and pigment contents, with correlation coefficients not exceeding 0.30, indicates that the fresh-weight benefit of the treatment cannot be explained simply by preserved chlorophyll; other processes, such as osmotic adjustment, membrane stability, or ion homeostasis, are likely contributing.

The proline data illustrate this point nicely. Proline rose with increasing salinity in the selenium-treated and combined-treatment plants, consistent with induced TaP5CS expression, and proline serves multiple roles beyond osmotic adjustment: it scavenges reactive oxygen species directly, stabilizes proteins and membranes, and buffers cellular redox state. A treatment that enhances proline accumulation under salt stress therefore plausibly contributes to the observed biomass protection through mechanisms invisible to chlorophyll measurements. Disentangling how much of the growth benefit flows through osmotic protection versus antioxidant reinforcement versus ion management will require the kind of integrative physiological follow-up the authors themselves call for.

From an applied perspective, the study sits within a growing literature on biostimulants as complements to conventional breeding and soil management for salinity adaptation. Breeding for salt tolerance in wheat has proven slow because tolerance is controlled by many genes of modest effect and is strongly environment-dependent. Foliar interventions offer a complementary route: they can be applied reactively when salinity is known to be a problem, combined with existing agronomic practice, and adjusted by dose and timing. The caveats the authors raise—uncharacterized formulation physics, seedling-stage results only, controlled-environment conditions, and no field validation—are the standard hurdles between a promising greenhouse result and a usable product, and their candor about them strengthens rather than weakens the study’s contribution. The work was supported by Hungarian national research funding through the Thematic Excellence Program and the NRDI Fund, and the article is published open access under a Creative Commons license, making the full dataset and methods available to any research group wishing to build on these findings.

Subject of Research: Foliar chitosan–selenite biostimulant effects on wheat seedlings under salt stress

Article Title: Foliar chitosan–selenite formulation improves wheat seedling growth under NaCl irrigation

Article References: Gholizadeh, F., Fábián, A., Sohail, H., Majláth, I., & Janda, T. (2026). Foliar chitosan–selenite formulation improves wheat seedling growth under NaCl irrigation. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10095-7

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10095-7

Keywords: wheat, salinity stress, chitosan, selenium, foliar application, biostimulants, gene expression, antioxidant defense, proline, confocal microscopy, plant physiology, NaCl

Selenium biofortification through foliar application has long been recognized as a promising strategy for improving the nutritional quality of staple crops. Unlike soil application, foliar sprays deliver selenium directly to the plant’s photosynthetic tissues, bypassing soil chemistry complications such as pH-dependent availability and microbial immobilization. Yet the integrated effects of foliar selenium on flax productivity, seed nutritional quality, and the molecular mechanisms governing these responses had remained insufficiently characterized—until now.

The researchers tested five different rates of foliar sodium selenite (Na2SeO3) application, ranging from 10 to 90 grams per hectare, alongside a water-sprayed control. What they discovered was strikingly rate-dependent. The 50 grams per hectare treatment, designated T3, produced the highest seed yield in both experimental years, delivering an 8.74 to 9.91 percent increase over the unsprayed control. This yield advantage arose primarily through increased capsule numbers per plant and greater seed counts per capsule—two agronomic traits that directly determine the reproductive output of the flax plant.

Photosynthetic performance told a complementary story. Under T3, flax plants exhibited elevated net photosynthetic rate and increased stomatal conductance, while intercellular CO2 concentration dropped by 24.54 percent. This combination indicates that the selenium-treated plants were consuming CO2 more rapidly through enhanced carbon fixation, drawing down the internal CO2 pool even as their stomata opened wider to admit more atmospheric carbon. The result is a more efficient photosynthetic engine, capable of channeling greater assimilate into developing seeds.

Beyond photosynthesis, the 50 grams per hectare treatment also produced the most favorable antioxidant profile in the seeds. Superoxide dismutase activity—the first line of enzymatic defense against reactive oxygen species—reached its highest level under T3, while malondialdehyde content, a widely used biomarker of lipid peroxidation and oxidative membrane damage, fell to its lowest. This dual pattern suggests that moderate selenium application primes the seed’s redox defense system without triggering the oxidative stress that higher selenium doses might induce.

Seed selenium content increased in a dose-dependent manner across all treatments, peaking under the 90 grams per hectare treatment at 21.96-fold that of the control. However, the 50 grams per hectare treatment achieved a 15.60-fold increase while simultaneously improving fatty acid quality: linoleic acid content rose by 18.51 percent and linolenic acid content by 4.85 percent. These two essential fatty acids, which humans cannot synthesize and must obtain from dietary sources, are the principal nutritional reasons flax oil commands premium market value.

To understand the molecular machinery underlying these physiological changes, the team performed RNA sequencing on seeds from the control and T3 treatments. The analysis identified 5,203 differentially expressed genes—2,523 upregulated and 2,680 downregulated—spanning a remarkable breadth of biological processes. Functional enrichment analysis revealed major clusters in photosynthesis and carbon metabolism, redox-related processes, selenium-associated metabolism, and lipid and fatty-acid metabolism. The scale of the transcriptional response underscores that foliar selenium is not a narrow nutritional intervention but a systemic signal that reprograms seed development at multiple levels.

Complementing the transcriptomic data, a 4D label-free proteomic analysis identified 76 differentially expressed proteins, comprising 23 upregulated and 53 downregulated proteins. These proteins clustered around antioxidant and detoxification responses, photosynthesis and energy metabolism, and lipid metabolism. Notably, the integration of transcriptomic and proteomic datasets revealed limited overlap between the two molecular layers: only eight gene-protein pairs showed significant alteration at both the transcript and protein levels. This limited concordance is a well-known feature of plant molecular biology, reflecting the complex post-transcriptional and post-translational regulation that separates messenger RNA abundance from actual protein accumulation.

The eight concordant gene-protein pairs included proteins involved in late embryogenesis abundant (LEA) responses, pathogenesis-related protein 5, and plastid lipid-associated proteins—molecules that collectively point to enhanced seed maturation, defense priming, and lipid body organization under moderate selenium treatment. Their dual-level confirmation provides the strongest molecular evidence in the study that selenium application genuinely rewires seed biology rather than merely altering gene expression patterns that never materialize as protein changes.

The findings carry practical significance for agricultural systems seeking to combat selenium deficiency through crop biofortification. By identifying 50 grams per hectare as the optimal rate—the treatment that maximizes yield, antioxidant status, and fatty acid quality simultaneously—the study offers a rational basis for optimizing foliar sodium selenite application in flax production. At the same time, the integrated multi-omics framework demonstrates that the molecular response to foliar selenium encompasses carbon metabolism, redox regulation, selenium-associated metabolism, lipid metabolism, and seed development, providing a mechanistic foundation that could guide biofortification strategies in other oilseed crops as well.

Subject of Research: Plant Molecular Biology

Article Title: Transcriptomic, proteomic, and physiological comparative analyses of foliar selenium application in flax

Article References: Wang, W., Su, F., Chang, B., & Du, J. (2026). Transcriptomic, proteomic, and physiological comparative analyses of foliar selenium application in flax. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10099-3

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10099-3

Keywords: selenium biofortification, flax, foliar application, transcriptomics, proteomics, fatty acids, antioxidant, seed yield, BMC Plant Biology, plant physiology, Transcriptomic, proteomic

The experimental design was straightforward but thorough. The team worked with leaves growing on one-year-old culms of Fargesia yunnanensis, a clumping bamboo species native to southwestern China and ecologically significant both as a panda food source and as a fast-growing woody grass with considerable economic value. Over the course of the experiment, the researchers sprayed the leaves with glycine solutions at six concentrations: 0, 2, 4, 6, 8, and 10 millimoles per liter, with the zero concentration serving as the control. Leaves were then harvested at different sampling times, allowing the investigators to track not only how much glycine was applied but also when its effects became visible. Both concentration and timing, the study found, significantly influenced a wide range of leaf traits.

The morphological results were unambiguous. Appropriate concentrations of glycine promoted leaf growth and altered the internal anatomy of the leaves, changes that matter because leaf structure governs how efficiently a plant can capture light, exchange gases, and transport water and nutrients. Beyond architecture, the treatment also shifted the leaf’s moisture content and nitrogen status, two parameters tightly linked to photosynthetic capacity. Nitrogen is a core component of chlorophyll and of the enzymes that drive photosynthesis, so an improvement in leaf nitrogen status following an amino acid spray is biologically coherent: glycine can be absorbed directly through the leaf surface and incorporated into the plant’s nitrogen economy without the energetic cost of reducing nitrate.

Photosynthetic pigments told a more nuanced story. Chlorophyll and related pigment concentrations generally rose at moderate glycine concentrations before declining at the highest doses, producing an initial increase followed by a decrease as concentration climbed. This bell-shaped response is a familiar pattern in plant nutrition research, where a beneficial input becomes counterproductive past a threshold. It suggests that while leaves welcome a moderate amino acid supplement, excessive glycine may disturb metabolic balance, possibly through osmotic stress at the leaf surface or through feedback inhibition of nitrogen assimilation pathways. For practitioners, the message is that more is not better; precision matters.

Perhaps the most technically revealing part of the study concerns carbohydrates. Glycine application generally elevated the contents of soluble sugars, starch, and total non-structural carbohydrates, the currency of plant growth and storage. Soluble sugar content peaked under the 8 millimole per liter treatment, whereas starch and total non-structural carbohydrate contents were generally highest under the 6 millimole per liter treatment. To understand the mechanism behind these shifts, the researchers measured the activities of the enzymes that orchestrate sucrose and starch metabolism, including soluble acid invertase, cell wall invertase, sucrose synthase, sucrose phosphate synthase, ADP-glucose pyrophosphorylase, soluble starch synthase, granule-bound starch synthase, and starch phosphorylase. Glycine significantly modulated these enzymatic activities, indicating that the amino acid influences not just how much carbon the leaf accumulates but how that carbon is synthesized, converted between sugar and starch forms, and stored.

This enzymatic dimension is what elevates the study beyond a simple growth trial. Sucrose phosphate synthase and sucrose synthase sit at the heart of sucrose biosynthesis and turnover, while ADP-glucose pyrophosphorylase is the classic rate-limiting enzyme of starch synthesis, and the starch synthases and phosphorylase determine how starch granules are built and remobilized. By showing that foliar glycine shifts the activity of this entire enzymatic network, the researchers provide a mechanistic explanation for the observed carbohydrate accumulation: the leaves are not merely receiving more carbon, they are actively reprogramming the pathways that partition that carbon between immediate energy use, transport, and long-term storage. Such partitioning decisions ultimately shape culm vigor, shoot elongation, and the overall productivity of the bamboo stand.

The second pillar of the study is oxidative stress. Photosynthesis inevitably generates reactive oxygen species, and when stress disrupts metabolism these molecules accumulate and damage membranes, proteins, and DNA. Plants defend themselves with an enzymatic antioxidant system, chief among it superoxide dismutase, peroxidase, and catalase. The study found that glycine application generally enhanced the activities of all three enzymes while simultaneously reducing the contents of malondialdehyde, a standard marker of lipid peroxidation and membrane damage, and hydrogen peroxide, a reactive oxygen species itself. In other words, glycine-treated leaves mounted a stronger antioxidant defense and suffered less oxidative damage, a combination that supports sustained photosynthetic performance and healthier leaf aging.

Correlation analysis wove these threads together, identifying statistically meaningful associations among leaf morphological traits, nitrogen status, carbohydrate metabolism, and antioxidant responses. This systems-level view reinforces the idea that the observed growth promotion is not a single isolated effect but the product of coordinated physiological change: better nitrogen status supports pigment synthesis and enzyme production, improved carbon metabolism supplies the energy and skeletons for growth, and a reinforced antioxidant system protects the machinery that makes both possible. Among all the concentrations tested, the 6 millimole per liter treatment elicited the most favorable overall response under the experimental conditions, emerging as the optimal dose in this study, with 8 millimoles per liter notable specifically for sugar accumulation.

The practical implications extend well beyond the laboratory. Bamboo is one of the fastest-growing plants on Earth and an increasingly important material for sustainable construction, paper, textiles, and carbon sequestration projects, yet its nutrient management remains less refined than that of major crops. Foliar fertilization offers a targeted, efficient alternative to soil fertilization, delivering nutrients directly to the photosynthetic tissue and reducing losses to leaching and soil fixation. The authors position their findings as a reference for foliar glycine application in bamboo nutrient management, while cautioning that field validation will be needed before the treatment can be recommended at scale. Variables such as climate, leaf age, application frequency, and formulation will all require testing under real plantation conditions.

Scientifically, the study adds to a growing body of evidence that amino acids are not merely building blocks for proteins but active signaling and metabolic agents in their own right. Glycine participates in one-carbon metabolism, contributes to glutathione synthesis, a central antioxidant molecule, and can be taken up intact by plant tissues. The results from Fargesia yunnanensis suggest that supplying this humble molecule through the leaf surface can ripple outward through nitrogen assimilation, pigment biology, carbohydrate enzymology, and stress defense simultaneously. For a plant as economically and ecologically significant as bamboo, a single, inexpensive spray that strengthens leaves on multiple fronts is an appealing proposition, and this research provides the physiological groundwork that future field trials can build upon.

Subject of Research: Effects of foliar glycine application on leaf development, carbon metabolism, and antioxidant defense in Fargesia yunnanensis

Article Title: Foliar glycine enhances leaf development by improving carbon metabolism and antioxidant defense in Fargesia yunnanensis

Article References: Chen, Y., Ran, J., Liu, J., & Wang, S. (2026). Foliar glycine enhances leaf development by improving carbon metabolism and antioxidant defense in Fargesia yunnanensis. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10118-3

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10118-3

Keywords: Fargesia yunnanensis, glycine, foliar application, leaf development, carbon metabolism, non-structural carbohydrates, sucrose metabolism, starch metabolism, antioxidant enzymes, superoxide dismutase, malondialdehyde, bamboo nutrient management

The research, led by Huida Lian and Cheng Qin with colleagues at the University of Changzhi, Northwest A&F University, Shanxi Normal University, and Shanxi Agricultural University in China, set out to answer a question that has lingered in plant physiology for decades: can foliar-applied rare earth elements meaningfully interact with soil phosphorus supply to shape crop performance from the leaf to the seed? Earlier work by some of the same team had shown that lanthanum chloride could boost growth and phosphorus acquisition in phosphorus-limited adzuki bean seedlings, but the mechanism remained murky, and field-scale evidence was thin. The new study moves the question from the greenhouse into real agronomic conditions.

The experimental design was deliberately straightforward. Over two growing seasons, 2023 and 2024, the researchers grew mung bean under six treatment combinations: two soil phosphorus regimes, one deficient and one sufficient with 80 kilograms per hectare of superphosphate, crossed with three foliar lanthanum concentrations of zero, 50, and 100 millimolar. Across the treatments they tracked a chain of measurements that reads like a tour of plant metabolism: leaf chlorophyll content measured as SPAD values, gas exchange parameters including net photosynthetic rate, stomatal conductance, intercellular carbon dioxide concentration, and transpiration rate, the activities of key enzymes in nitrogen and carbohydrate metabolism, the expression of photosynthesis- and sugar-related genes, and finally the accumulation of phosphorus, nitrogen, and other minerals in the harvested seeds.

The damage inflicted by phosphorus deficiency alone was severe and quantifiable. Compared with phosphorus-sufficient plants, deficient plants lost 20.95 percent of their leaf chlorophyll as measured by SPAD values and suffered a 31.62 percent drop in net photosynthetic rate. The consequences rippled all the way to the grain: seed phosphorus content fell by 45.9 percent and seed nitrogen content by 21.9 percent. These numbers capture a familiar cascade. When phosphorus is scarce, the light reactions of photosynthesis falter because ATP synthesis and the regeneration of phosphorylated intermediates in the Calvin-Benson cycle depend on a steady phosphorus supply. Less carbon fixed means less sugar exported to developing seeds, and the seeds themselves, which require phosphorus for phytate storage compounds and nitrogen for storage proteins, end up nutritionally impoverished.

The lanthanum sprays changed that picture in a striking way. Under phosphorus deficiency, the 100 millimolar foliar treatment partially restored photosynthetic efficiency, reactivated a suite of key metabolic enzymes, and enhanced both carbohydrate synthesis and the translocation of nutrients into the seeds. Among the enzymes that responded were nitrate reductase and glutamine synthetase, the two gatekeepers of nitrogen assimilation, and sucrose phosphate synthase and sucrose synthase, which together govern how efficiently photosynthetic carbon is converted into the transport sugar sucrose and then metabolized in sink tissues. In other words, lanthanum did not merely green the leaves; it appeared to re-tune the entire source-to-sink pipeline that carries carbon and nitrogen from the canopy into the grain.

The molecular data gave that physiological story a concrete genetic footing. Gene expression analysis revealed that lanthanum upregulated a cluster of photosynthesis-related genes encoding extrinsic proteins of photosystem II, including PsbO, PsbP, PsbQ, PsbY, and Psb28. These proteins stabilize the oxygen-evolving complex of photosystem II, the molecular machine that splits water and drives the electron transport chain at the heart of the light reactions. Their upregulation suggests that lanthanum helps maintain the structural and functional integrity of the photosynthetic apparatus precisely where phosphorus stress would be expected to degrade it. Earlier biochemical studies had reported that rare earth ions such as lanthanum and cerium can promote the formation of functional complexes between rubisco and rubisco activase in spinach, providing a plausible additional route by which the element could enhance carbon fixation.

Even more dramatic was the response of the carbohydrate metabolism genes. Expression of SuSy1, one of the genes encoding sucrose synthase, increased up to 20.11-fold under the combined treatment of optimal phosphorus and lanthanum, with SuSy2 and SS1 also upregulated. Sucrose synthase is central to seed development because it cleaves incoming sucrose into uridine diphosphate glucose and fructose, feeding starch biosynthesis and cell wall construction in the filling grain. A twentyfold increase in the transcript abundance of this gene under combined optimal phosphorus and lanthanum points to a coordinated transcriptional program that prioritizes carbon allocation to the seed. The path analysis presented by the authors, with standardized coefficients linking photosynthetic parameters, enzyme activities, and seed mineral contents, supports the idea that these effects are mechanistically interconnected rather than isolated correlations.

Why would a rare earth element exert this kind of influence? Lanthanum is not a plant nutrient in the classical sense, and its chemistry is dominated by the trivalent lanthanum ion, which mimics calcium in many biological contexts. Research over the past two decades has shown that rare earth elements can activate endocytosis in plant cells, trigger calcium-dependent signaling pathways, and modulate the activity of calcium-binding proteins involved in photosynthesis. There is also a practical advantage to applying lanthanum as a foliar spray: it bypasses the soil entirely, avoiding the notorious tendency of lanthanide ions to precipitate with phosphates and become immobilized in soil particles. Foliar delivery places the element directly on the leaf surface, where it can be absorbed and act on photosynthetic tissue without ever encountering the soil chemistry that would otherwise neutralize it.

The study is not without caveats that any careful reader should weigh. The concentrations tested, 50 and 100 millimolar, are high relative to typical micronutrient sprays, and the long-term environmental behavior of rare earth elements in agricultural systems, including their accumulation in soils and food chains, remains an active area of research. Rare earth elements have documented effects on soil microbial communities, and excessive exposure can be toxic to plants, as studies on rice seedlings have shown. The authors report that lanthanum application independently improves photosynthetic performance, carbohydrate metabolism, and nutrient translocation, thereby alleviating phosphorus-deficiency stress and enhancing mung bean productivity and seed nutritional quality in phosphorus-limited agricultural systems, but translating a two-year field result into agronomic practice will require attention to dose, formulation, residue dynamics, and regulatory frameworks that currently treat rare earth elements with caution.

Nevertheless, the findings land at a consequential moment. Global phosphorus rock reserves are finite and unevenly distributed, fertilizer prices are volatile, and phosphorus-use efficiency in most cropping systems remains low, with a large fraction of applied phosphate locked into unavailable soil pools within weeks. Strategies that allow crops to maintain yield and seed quality under reduced phosphorus inputs are therefore valuable on multiple fronts. If the lanthanum effect documented here can be reproduced across seasons, soil types, and crop species at lower effective doses, foliar rare earth application could become a targeted tool in the broader toolkit of phosphorus-efficient agriculture, sitting alongside phosphorus-solubilizing microbes, root architectural breeding, and precision fertilization. For a crop as nutritionally and culturally important as mung bean, a single foliar spray that lifts photosynthesis, reprograms sugar metabolism, and enriches the grain offers a glimpse of how trace chemistry might help close the yield gap on the world’s phosphorus-poor soils.

Subject of Research: Interactive effects of soil phosphorus levels and foliar lanthanum application on photosynthesis, carbohydrate metabolism, gene expression, and seed mineral accumulation in mung bean

Article Title: From photosynthesis to grain formation: a comprehensive evaluation of phosphorus – lanthanum combined effects on mung bean (Vigna radiata L.) cultivation

Article References: Lian, H., Zhang, X., Shi, C., Shen, J., Li, L., Wu, S., Dong, J., Zhang, Z., He, Z., Qin, C., & Zhang, S. (2026). From photosynthesis to grain formation: a comprehensive evaluation of phosphorus – lanthanum combined effects on mung bean (Vigna radiata L.) cultivation. Plant and Soil. https://doi.org/10.1007/s11104-026-09088-0

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09088-0

Keywords: mung bean, phosphorus deficiency, lanthanum, rare earth elements, photosynthesis, carbohydrate metabolism, sucrose synthase, photosystem II, seed quality, foliar application, plant nutrition, Vigna radiata

The research addresses a pressing challenge in modern horticulture. High-density orchards, which pack dwarfing rootstocks and slender trees into tight rows to maximize early returns, demand intensive inputs of fertilizers and agrochemicals. Input costs have been climbing steadily, while environmental scrutiny of conventional chemical programs has intensified. Growers and scientists alike have been searching for eco-friendly alternatives that can sustain productivity without compromising fruit quality or soil health. Plant biostimulants, substances that modulate plant growth and stress responses rather than simply feeding crops, have emerged as one of the most promising candidates, and weed-derived formulations are an especially attractive class because their raw material is abundant, cheap and otherwise destined for disposal.

What makes weeds chemically interesting, the authors note, is their diverse arsenal of bioactive secondary metabolites. Plants that thrive in harsh, competitive environments often accumulate phenolics, alkaloids, terpenoids and other compounds that, when extracted and applied to crops, can influence hormone signaling, nutrient uptake and stress tolerance. Rather than treating these formulations as a generic tonic, the Indian team hypothesized that timing matters enormously. A tree’s needs shift dramatically across its phenological calendar, from budbreak and flowering through fruit set, cell expansion and ripening, so a spray that helps at one stage may be irrelevant or wasteful at another. Their experiment was designed to test whether matching applications to nine distinct phenological stages would unlock the full potential of the bio-formulations.

The field trials were conducted during 2024 and 2025 at two contrasting orchard sites in the apple-growing hills of Himachal Pradesh. One site, at Nauni, used trees on the dwarfing EMLA9 rootstock, while the other, at Kandaghat, used trees on the more vigorous MM111 rootstock. Both orchards were managed under high-density systems, the very conditions where input costs and tree stress tend to be most acute. The researchers employed a split-plot design with four replications, a statistically robust layout that allowed them to separate treatment effects from site and block variation. Five treatments were compared, each consisting of a different combination of stage-specific bio-formulation applications, alongside a control that received only water sprays.

The standout treatment, designated T1, involved sequential applications of the bio-formulations across all nine phenological stages, effectively accompanying the tree through its entire productive cycle. The results were striking. Fruit set rose from 38.56 percent in the control trees to 44.67 percent in the T1 trees, a meaningful gain in a crop where every percentage point of set translates directly into marketable fruit. More dramatically, yield per tree climbed from 2.81 kilograms to 4.83 kilograms, an increase of roughly 72 percent. For high-density growers calculating returns per hectare, a jump of that magnitude, achieved without synthetic agrochemical inputs, represents a potentially transformative economics shift.

Fruit quality, the attribute that ultimately determines price and consumer acceptance, improved alongside quantity. Apples from treated trees were measurably firmer, registering 7.67 kilograms per square centimeter of flesh resistance compared with 6.58 in controls, a difference that matters for shelf life, transport tolerance and the crisp bite that ‘Gala’ consumers expect. Total soluble solids, the standard proxy for sweetness measured in degrees Brix, rose from 10.83 to 12.44, while total sugar content increased from 9.91 percent to 11.19 percent. Taken together, these figures describe fruit that is not only more abundant but also sweeter, firmer and better suited to the demands of long-distance supply chains.

Beneath the visible improvements in the fruit, the leaf analysis revealed a physiological mechanism at work. Concentrations of the three primary macronutrients in the foliage all rose significantly relative to the control: nitrogen increased by 29.2 percent, phosphorus by 50.0 percent and potassium by 18.6 percent. Phosphorus, often the most limiting nutrient in hill soils, plays central roles in energy transfer and flowering, while potassium governs fruit size, sugar accumulation and firmness. The pattern of nutrient enhancement aligns neatly with the observed gains in fruit set, sweetness and texture, suggesting that the bio-formulations improved the trees’ ability to acquire and mobilize nutrients rather than merely stimulating growth at the expense of quality.

To test whether these improvements were statistically coherent rather than a collection of coincidental effects, the team applied two complementary analytical tools. Pearson’s correlation analysis revealed significant positive associations among vegetative growth, nutrient status, yield and fruit quality traits, indicating that the treatments lifted the entire performance profile of the trees in concert. Principal component analysis then condensed the many measured variables into a few underlying dimensions, and the results were unusually clean: the first two components together explained 97.57 percent of the total variation, with the first component alone accounting for 68.96 percent. When a small number of components capture nearly all the variation in an experiment, it signals that the treatments produced a strong, systematic biological response rather than scattered, noise-driven differences.

The implications extend well beyond one cultivar and one growing season. Because the formulations are derived from weeds, they offer a circular-economy twist: plants that compete with crops for water and nutrients can be harvested, processed and returned to the orchard as a growth-enhancing spray. That could reduce both the labor of weed management and the expenditure on synthetic inputs, a double saving for smallholder growers in the Himalayan apple belt who face some of the steepest production costs in the industry. The phenology-based protocol also gives growers a practical scheduling framework, since the nine application stages correspond to observable milestones such as budbreak, bloom and fruit development that are already part of standard orchard record-keeping.

Cautions remain before the practice can be widely recommended. The study covered two seasons at two sites on a single cultivar, and the published version is an early-release, peer-reviewed accepted manuscript that will be replaced by a final Version of Record. Follow-up work will need to establish how the formulations perform across different rootstocks, climates and cultivars, and to characterize the active compounds responsible for the effects. Nevertheless, the core result stands on firm statistical ground: timed applications of weed-derived bio-formulations increased fruit set, boosted yield by more than 70 percent, improved firmness and sweetness, and elevated leaf nitrogen, phosphorus and potassium in high-density ‘Gala Schniga Schnico’ apple orchards. If those gains hold at scale, the humble weeds at the edge of the orchard may become one of its most valuable assets.

Subject of Research: Phenology-based application of weed-derived plant biostimulants in high-density apple orchards

Article Title: Phenology-based application of weed-derived bio-formulations enhances growth, yield, fruit quality and leaf nutrient status of ‘Gala Schniga Schnico’ apple under high-density orchard systems

Article References: Kumar, P., Ladon, T., Sharma, A., Devi, M., Vikram, A. K., Chauhan, J. K., & Rana, R. K. (2026). Phenology-based application of weed-derived bio-formulations enhances growth, yield, fruit quality and leaf nutrient status of ‘Gala Schniga Schnico’ apple under high-density orchard systems. BMC Plant Biology. https://doi.org/10.1186/s12870-026-09504-8

Image Credits: AI Generated

DOI: 10.1186/s12870-026-09504-8

Keywords: weed-derived bio-formulations, plant biostimulants, phenology, apple production, high-density orchards, fruit quality, fruit set, leaf nutrient status, sustainable horticulture, Gala apple, foliar application, BMC Plant Biology

The research, led by Qi Liu and Xuchao Sun of Huazhong Agricultural University and Yunnan Agricultural University together with colleagues, was conducted at two field sites where the soil was co-contaminated with cadmium and lead. Rather than treating the soil, the team applied seven different foliar formulations at two critical points in the maize life cycle: the vegetative stage, when the plant is building its leafy machinery, and the reproductive stage, when grain filling begins. This timing matters because the two stages rely on different plumbing. During growth, the xylem, the plant’s upward water highway, carries metals from roots to shoots along with the transpiration stream. But grain loading happens mainly through the phloem, the sugar-transport network that feeds developing kernels. The team’s central hypothesis was that if they could encourage leaves to grab and hold onto metals, less would be remobilized into the phloem and shipped to the grain.

Two of the seven formulations stood out decisively. The first, labeled PPF, combined potassium silicate, sodium selenite, and chitosan, a sugar derived from crustacean shells. The second, YZ-3, blended potassium fulvate, boric acid, and zinc sulfate. Both mixtures enhanced transpiration and photosynthesis, and grain yields rose by 23.5 to 30.4 percent compared with untreated controls. At the same time, cadmium and lead concentrations in the grain fell by 44.4 to 60.6 percent. That dual outcome is the headline result: the plants grew better, not worse, even as the edible fraction became dramatically cleaner. The mechanism, according to the measurements, was a shift in metal allocation at the whole-plant level, with proportionally more cadmium and lead retained in leaves and less exported to the grain.

To understand where the metals were going inside leaf cells, the researchers dissected the subcellular distribution of cadmium and lead, separating cell walls, soluble fractions, and organelles. The pattern they found was elegant and, in a sense, chemically intuitive. Nearly half of the cadmium in treated leaves, between 48.4 and 49.7 percent, ended up in the soluble fraction, where it was associated with elevated levels of oxalic, malic, and citric acids. These small organic acids are classic metal chelators; they bind cadmium ions into stable complexes that are effectively neutralized, floating harmlessly in the vacuole-like soluble compartment rather than interfering with biochemistry. Cadmium, in other words, was being dissolved into a chemical safe deposit box.

Lead told a different story. Up to 60.1 percent of the lead in treated leaves was locked into the cell wall fraction, and this sequestration tracked with two measurable changes in pectin chemistry: increased pectin content and decreased methylation. Pectin, the gel-like polysaccharide abundant in primary cell walls, carries carboxyl groups that act as cation exchange sites. When pectin is less methylated, more of those carboxyl groups are exposed and negatively charged, giving divalent lead ions more places to bind. The formulation appears to have nudged the cell wall toward a lead-trapping configuration, essentially thickening and chemically arming the barrier that surrounds every cell. Meanwhile, the fraction of both metals residing in organelles, the sensitive metabolic cores of the cell, dropped to just 6.2 to 10.8 percent, minimizing direct toxicity to chloroplasts and mitochondria.

This differentiated handling, cadmium chelated in solution and lead fixed in walls, provides what the authors describe as a physiological basis for why the two metals behave so differently in the plant. It also explains why the strategy works without stunting growth. By parking metals in compartments where they cannot do damage, the formulations allowed photosynthesis and gas exchange to proceed at full throttle. Enhanced transpiration, driven by healthier leaves, pulled more water and nutrients up through the xylem, supporting the larger yields, while the subcellular traps ensured that the increased metal traffic did not translate into greater grain contamination. The metals still entered the plant; they simply never reached the harvestable part in significant quantities.

The broader context makes these numbers significant. Global assessments published in recent years estimate that soil pollution by toxic metals threatens agriculture and human health on a massive scale, with cadmium being particularly insidious because it accumulates in staple grains at concentrations that pose chronic dietary risks. Cadmium damages kidneys and bones over long-term exposure, while lead impairs neurological development, and there is no safe threshold for lead in food. In many contaminated regions, farmers have no choice but to keep growing crops, which makes interventions that reduce grain metal loads without taking land out of production enormously valuable. Foliar sprays are cheap, easy to apply with existing equipment, and compatible with normal agronomic schedules, unlike soil excavation, chemical washing, or long fallow periods.

The choice of ingredients also reflects a growing sophistication in the field. Silicon, delivered here as potassium silicate, is well known for strengthening cell walls and mitigating metal stress in grasses. Selenium has been shown in prior work to compete with cadmium for transport and binding sites, and chitosan can form films on leaf surfaces and modulate plant defense responses. Fulvic acid, a component of humic substances, can complex metals, while zinc is a classic antagonist of cadmium uptake because the two ions share transport pathways, so supplying abundant zinc can crowd cadmium out. Boron contributes to cell wall cross-linking, which may underpin the pectin changes observed in the study. The formulations are thus not exotic nanomaterials but combinations of inexpensive, widely available compounds, which improves the odds of real-world adoption.

There are, of course, caveats. The study was conducted at two field sites with specific soil chemistry, and metal bioavailability varies enormously with pH, organic matter, and mineralogy, so results will need validation across more diverse environments and growing seasons. The long-term effects of repeated spraying on soil biology and on the fate of the sequestered metals, which remain in the leaves and stover after harvest, also deserve attention, since crop residues returned to fields could theoretically recycle metals back into the soil. The authors note that data will be made available on request, and the work was funded by Chinese national and provincial science programs, reflecting the scale of the contamination challenge in Chinese farmland.

Even with those qualifications, the study offers a compelling proof of concept that the internal plumbing and chemistry of a crop can be steered from above, through the leaf, to produce cleaner food from dirtier ground. The idea that a simple spray can simultaneously raise yields and cut grain cadmium and lead by half challenges the assumption that food safety and productivity must trade off on contaminated land. If the approach generalizes, it could give farmers on polluted soils a practical tool that works with the plant’s own sequestration machinery, turning leaves into filters and keeping the poison out of the pantry.

Subject of Research: Foliar blocking agents that reduce cadmium and lead accumulation in maize grain by altering subcellular metal sequestration in leaves

Article Title: Limiting grain cadmium and lead accumulation in maize: foliar application of blocking agents to modulate subcellular sequestration

Article References: Liu, Q., Sun, X., Wang, S., Zhou, J., Bao, L., Zhou, W., & Zhang, N. (2026). Limiting grain cadmium and lead accumulation in maize: foliar application of blocking agents to modulate subcellular sequestration. Plant and Soil. https://doi.org/10.1007/s11104-026-09149-4

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09149-4

Keywords: maize, cadmium, lead, foliar application, heavy metals, subcellular partitioning, cell wall, pectin, organic acids, food safety, soil contamination, crop yield

The research team set out to test a straightforward hypothesis. Fulvic acid, the water-soluble fraction of humic substances, has long been known to behave like a plant biostimulant: it exhibits phytohormone-like activity, promotes cell elongation, stimulates plasma membrane H+-ATPase, and acts as a strong metal-complexing agent that enhances the uptake of macro- and micronutrients such as magnesium, calcium, iron, copper, manganese and zinc. Because glyphosate is known to disrupt the uptake and translocation of essential elements including calcium, magnesium, iron and manganese even at sublethal doses, the authors reasoned that fulvic acid might counteract several facets of glyphosate injury simultaneously, by supporting growth recovery, restoring nutrient acquisition and possibly stimulating antioxidant defences.

To model the problem, the researchers grew wheat cultivar Scepter in a glasshouse in sandy soil from the Shenton Park field station in Perth, amended with a balanced suite of basal nutrients. In preliminary experiments they simulated glyphosate drift at 1, 3, 5 and 10 percent of the recommended weed-kill rate of Roundup 360, applied with a laboratory boom sprayer at the Zadoks Z13 stage, when wheat seedlings have three leaves. Based on growth and physiological responses, they identified 3 percent of the recommended rate as a representative sublethal drift level near the maximum tolerance threshold, matching field observations that up to 10 percent of the applied herbicide rate can occur as drift under real conditions. All subsequent experiments used this 3 percent dose.

The first suite of experiments screened six fulvic acid concentrations, from 1 to 15 grams per litre, applied either three days before glyphosate or immediately before the herbicide on the same day. Moderate rates of fulvic acid alone were clearly beneficial: at 1 to 5 grams per litre, applied 15 days after sowing, shoot dry weight rose 15 to 22 percent above untreated controls, and 5 grams per litre at that early timing also increased root dry weight and fine root length. Higher rates of 7 to 15 grams per litre provided no growth benefit, and chlorophyll readings actually declined at the highest dose. This dose-dependence echoes a wider literature on humic and fulvic substances, where moderate concentrations typically stimulate growth while excessive amounts can inhibit it.

The protective story became more compelling when fulvic acid was combined with glyphosate. Compared with seedlings receiving glyphosate alone, those sprayed with fulvic acid at low to moderate rates showed significantly higher shoot and root dry weight, longer coarse roots, and higher leaf chlorophyll concentrations measured with a SPAD meter. Timing mattered: applying fulvic acid three days before glyphosate exposure generally outperformed applying it immediately before the herbicide. Shoot micronutrient status also recovered; concentrations of iron, manganese and zinc in shoots were significantly higher in glyphosate-plus-fulvic-acid treatments than in glyphosate alone, consistent with the compound’s established role as a natural chelator that mobilises metal ions within plant tissues.

The most striking result emerged in a third experiment in which fulvic acid was simply mixed into the glyphosate spray tank. Across all mixture treatments, shoot dry weight exceeded that of glyphosate-only plants, total root length returned to control values in almost every case, and chlorophyll concentrations were statistically indistinguishable from untreated seedlings. Glyphosate alone had sharply depressed shoot iron, manganese and zinc, yet the mixtures with 3, 7 or 10 grams per litre of fulvic acid restored iron to levels significantly above glyphosate treatment, while manganese and zinc concentrations rose across all mixtures, often matching the controls. In effect, the presence of fulvic acid in the spray solution appeared to neutralise nearly all visible and measurable glyphosate injury to the wheat seedlings.

Why would mixing the two chemicals be so effective? The authors propose a physicochemical explanation grounded in prior spectroscopy work. At the mildly acidic spray solution pH values measured in the study, between 5.12 and 5.29, both fulvic acid and glyphosate carry predominantly negative charges, but glyphosate’s protonated amine group can form electrostatic bonds with the negatively charged carboxylate groups of fulvic acid. Hydrogen bonding and metal-ion complexation may further promote their association. These interactions could reduce the pool of free glyphosate available for absorption into the leaf and for subsequent phloem-mediated translocation to growing points, thereby limiting the herbicide’s ability to reach and inhibit its target enzyme, 5-enolpyruvylshikimate-3-phosphate synthase, which synthesises the aromatic amino acids tryptophan, phenylalanine and tyrosine. Fulvic acid may also scavenge reactive oxygen species, indirectly reducing oxidative damage. The authors are careful to stress, however, that these mechanisms remain hypothetical in this study because glyphosate uptake, translocation and oxidative stress responses were not directly measured.

The study also revealed that protection is cultivar-dependent. In a fourth experiment, the optimum 5 grams per litre fulvic acid dose was tested on two wheat varieties previously identified as differing in glyphosate sensitivity: Scepter, the most sensitive, and Magenta, the least sensitive of five cultivars screened in earlier work. Magenta outperformed Scepter in shoot dry weight, fine and coarse root length, and micronutrient accumulation. Pre-application of fulvic acid three days before glyphosate raised shoot dry weight to control levels for both cultivars, while same-day application was largely ineffective. The mixture treatment significantly improved root dry weight in both cultivars and enhanced net photosynthetic rate, transpiration and stomatal conductance, with the gas exchange benefits differing between genotypes. A principal component analysis separated treatments into distinct clusters: fulvic-acid-only plants and controls grouped together on the high-biomass, high-photosynthesis side, glyphosate-only plants on the opposite side, and the combined treatments at intermediate positions, together explaining 82 percent of total variation across the measured traits.

The findings arrive at a time when growers and the scientific community increasingly recognise herbicide drift as a persistent agronomic and ecological problem, one that extends beyond wheat to affect native vegetation and non-target plant communities. A foliar biostimulant that is inexpensive, applied at low rates and derived from natural organic matter offers an attractive complement to drift-reduction measures such as nozzle selection, buffer zones and weather-aware spraying. The authors suggest practical implications in two directions. First, prophylactic fulvic acid sprays could be scheduled before likely drift exposure windows, given that pre-treatment proved more effective, presumably because it allows time for physiological and biochemical defence mechanisms to be activated before the stress arrives. Second, the strong protection from tank mixtures is intriguing scientifically but carries a major caveat: if fulvic acid completely eliminates glyphosate’s herbicidal effect, it cannot simply be added to routine weed-control sprays, since that would defeat the purpose of the herbicide.

Important questions remain before fulvic acid can be recommended at field scale. The experiments were conducted under controlled glasshouse conditions at only one drift dose and one growth stage, and the authors explicitly caution that field validation is required before agronomic recommendations can be made. The biochemical and molecular basis of the protection, including antioxidant enzyme responses and metal transporter activity, awaits direct investigation, which the group is pursuing in a separate study. Cultivar-specific responses also suggest that breeding programmes could exploit natural variation in glyphosate tolerance. Still, the core message is clear and pragmatic: timing a fulvic acid spray a few days ahead of anticipated glyphosate exposure, or understanding the chemistry of fulvic acid–glyphosate interactions, could give wheat seedlings a meaningful buffer against one of modern broadacre farming’s most insidious accidental threats.

Subject of Research: Alleviation of glyphosate drift damage in wheat seedlings using foliar fulvic acid application

Article Title: Foliar application of fulvic acid minimises the damage of glyphosate drift to wheat (Triticum aestivum L.) during early growth

Article References: Mandal, B. H., Hosenuzzaman, M., Solaiman, Z. M., & Rengel, Z. (2026). Foliar application of fulvic acid minimises the damage of glyphosate drift to wheat (Triticum aestivum L.) during early growth. Plant and Soil. https://doi.org/10.1007/s11104-026-09119-w

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09119-w

Keywords: glyphosate drift, fulvic acid, wheat, foliar application, herbicide damage, plant biostimulants, micronutrients, photosynthesis, EPSPS, cultivar tolerance, Plant and Soil, crop protection

The researchers began with sunflower leaf extract, chosen because sunflowers are rich in flavonoids and phenolic acids, phytochemicals that act as natural reducing and stabilizing agents for zinc ions. Twenty-five grams of air-dried, milled sunflower leaves were stirred into 500 milliliters of distilled water at 50 degrees Celsius for three hours to produce the extract. Zinc oxide solution was then added, acidified with hydrochloric acid, and heated to 80 degrees Celsius to encourage particle formation. Sodium hydroxide was added dropwise until the pH reached between 10 and 11, darkening the mixture and driving the nanoparticles to precipitate. After centrifugation, washing, and drying at 105 degrees Celsius, the team had a batch of biologically derived zinc oxide nanoparticles ready for rigorous characterization.

Fourier transform infrared spectroscopy revealed that the nanoparticles carried hydroxyl groups, amides, and carbon-hydrogen bonds as their major functional groups, fingerprints largely absent from the original leaf extract. The researchers interpreted these signatures as evidence that the zinc oxide had successfully complexed with biomolecules from the sunflower leaves. Scanning electron microscopy showed a smooth surface on the nanoparticles, in contrast to the rough texture of the raw extract, a difference the authors linked to enhanced adhesion, catalytic activity, and interaction with surrounding soil and plant molecules. Transmission electron microscopy revealed homogeneous, rod-shaped particles with an average diameter of just 4.19 nanometers, a size the team says likely boosts solubility and diffusion rates, key mechanisms for nutrient absorption in plant tissue.

X-ray diffraction confirmed a crystalline structure, with the highest diffraction intensity recorded in the nanoparticles between zero and 20 degrees. Energy-dispersive spectroscopy then quantified the elemental makeup: zinc dominated the nanoparticles at 50.24 percent, while silica was the major element in the leaf extract at roughly 70 percent. The authors argue that the high surface area, pure crystalline nature, and rod-like morphology of the particles give them the surface energy needed to propel physiological activities such as nutrient uptake, and that the presence of zinc itself likely enhanced the morphological, physiological, and biochemical changes observed in the treated eggplants.

To test the particles in living plants, the team grew eggplant seedlings in sandy-loam soil in the greenhouse and sprayed them with four concentrations of the nanoparticles, 25, 50, 75, and 100 percent, once every two weeks for eight weeks, alongside a control group watered with distilled water. The experiment followed a completely randomized design with five replications. The strongest concentration produced the most striking results: plants sprayed with 100 percent nanoparticles reached an average height of 19.93 centimeters and carried 34.75 leaves, with a leaf area of 86.77 square centimeters, a specific leaf area of 50.96 square meters per kilogram, and a leaf area index of 0.30 square meters per square meter. Relative growth rate peaked at 0.31 grams per square meter per day, while net assimilation rate and leaf area ratio were highest at the 75 percent concentration.

The biochemical story was equally revealing. Reactive oxygen species, the damaging molecules that plants generate under stress, were significantly downregulated in nanoparticle-treated plants. Malondialdehyde, a marker of lipid peroxidation, peaked at 23.23 micromoles per gram of fresh weight in control leaves, while hydrogen peroxide reached 41.82 nanomoles per gram of dry weight in control leaves and 26.98 nanomoles per gram in control roots. In contrast, the lowest values of these stress markers appeared in the leaves and roots of plants sprayed with the full-strength nanoparticle solution, suggesting the particles had ameliorated oxidative damage rather than provoking it.

Antioxidant enzyme activity told a complementary story. Superoxide dismutase, ascorbate peroxidase, catalase, glutathione reductase, and glutathione S-transferases were all substantially upregulated in the leaves of control plants, which the researchers interpret as a defensive response to the reactive oxygen species accumulating in untreated tissue. Once the nanoparticles suppressed those reactive species, the antioxidant machinery no longer needed to run at full tilt, and enzyme activities dropped to their lowest levels in the 100 percent treatment group. The authors note that zinc is known to bind amino acids, restrict reactive oxygen accumulation, improve antioxidant activity, and maintain osmotic balance, mechanisms that may underpin the stress-buffering effect they observed.

Nutritional analysis added a final layer of significance. Moisture, dry matter, and fat content were highest in control plants, but ash, crude fiber, crude protein, and carbohydrate all increased significantly in plants sprayed with 100 percent nanoparticles, with crude protein reaching 2.45 percent and carbohydrate 3.20 percent. Mineral profiles shifted as well: sodium, potassium, and calcium peaked in the 100 percent treatment, while magnesium at 58.80 milligrams per 100 grams and phosphorus at 90.86 milligrams per 100 grams were significantly higher in plants treated with the 75 percent concentration. The team attributes these gains to the formation of new leaves and biomass, and to the nanoparticles’ ability to distribute nutrients effectively through plant tissue, linking nutritional status to photosynthetic potential.

The implications reach well beyond one vegetable. Eggplant, a Solanaceae crop consumed widely across Africa for food and indigenous purposes, often suffers from the continuous application of synthetic fertilizers, which mineralize slowly due to low surface area and contribute to leaching, erosion, and soil degradation. Ultrafine, plant-derived particles could offer a sustainable alternative, rejuvenating depleted soils and regulating metabolic processes in crops. The authors conclude that zinc oxide nanoparticles at 100 and 75 percent concentrations should be considered as flora-based fertilizers to improve eggplant growth and buffer the plants against erratic climatic conditions.

Still, the researchers are careful to flag what their study did not do. They did not optimize concentrations of the sunflower leaf extract itself, assess its potential as a biofertilizer, or evaluate toxicity, and they recommend that future work investigate the single and synergistic effects of zinc oxide nanoparticles and sunflower leaf extract, along with their potential toxicological risks. That caution matters: reviews of zinc oxide nanoparticles in plant science have emphasized the need to understand ecological risks and dose-dependent effects before widespread deployment. For now, the Lagos State University team’s rod-shaped, 4-nanometer particles stand as a compelling proof of concept that a common garden flower can help manufacture a fertilizer capable of growing taller, greener, and more nutritious eggplants.

Subject of Research: Green-synthesized zinc oxide nanoparticles as foliar nanofertilizers modulating growth, oxidative stress, and nutrition in eggplant

Article Title: Characterization and modulatory influence of flora-based zinc oxide nanoparticles on morpho-physiological and biochemical changes in eggplant

Article References: Ojewumi, A. W., Osifeko, O. L., Fawibe, O. O., Shotonwa, I. O., Sheily, N. E., Akinyemi, O. F., Omolokun, K. T., Oyelami, B. A., Adelugba, D. O., & Ojekale, A. B. (2026). Characterization and modulatory influence of flora-based zinc oxide nanoparticles on morpho-physiological and biochemical changes in eggplant. BMC Agriculture, 2(1), Article 6. https://doi.org/10.1186/s44399-025-00028-4

Image Credits: AI Generated

DOI: 10.1186/s44399-025-00028-4

Keywords: zinc oxide nanoparticles, eggplant, sunflower leaf extract, green synthesis, nanofertilizer, foliar application, reactive oxygen species, antioxidant enzymes, plant nutrition, sustainable agriculture, Lagos State University, BMC Agriculture

Protein hydrolysates are mixtures of free amino acids and short peptides produced by enzymatically or chemically cleaving protein-rich raw materials. Under European Union Regulation 2019/1009, plant biostimulants are formally defined as products that stimulate plant nutrition processes independently of their nutrient content, improving nutrient use efficiency, abiotic stress tolerance, crop quality, or nutrient availability in the root zone. Within this category, protein hydrolysates have become one of the most intensively studied groups, valued both for their physiological effects on crops and for their role in valorizing agro-industrial waste streams. Yet despite growing commercial interest, important questions remain about how these products work, which formulations are most effective, and how application rate shapes the response.

The Bonn team, led by Fereshteh Bayat together with Thuy Huu Nguyen and Thomas Gaiser of the Institute of Crop Science and Resource Conservation, set out to test a specific hypothesis: that hydrolysates enriched in small peptides under 3 kilodaltons could enhance vegetative growth and water-use efficiency even when sprayed only twice, at very low concentrations. They compared two novel formulations supplied by Croptivate BV in the Netherlands. MP2025 is an enzymatically hydrolyzed product derived from maize, while AM2025 originates from the yeast Saccharomyces cerevisiae. Both were applied as foliar sprays at 0.05 and 0.1 percent by volume — equivalent to 0.5 and 1.0 milliliters per liter — which is substantially below the 2 to 5 milliliters per liter range commonly reported in the experimental literature.

The experiments were conducted in 2025 under tightly controlled greenhouse conditions at the University of Bonn, using two model crops chosen for their rapid early growth: cherry tomato (Solanum lycopersicum cv. Sungold) and common bean (Phaseolus vulgaris cv. Saxa). Plants were grown in a cocopeat-perlite substrate, irrigated with Hoagland nutrient solution, and maintained at day and night temperatures of 22 and 18 degrees Celsius with photosynthetically active radiation held near 400 micromoles per square meter per second. Sprays were applied at the appearance of the first true leaves and again seven days later, delivered at a volume equivalent to roughly 600 liters per hectare. Each treatment comprised eight replicate plants arranged in a factorial completely randomized design, with formulation and dose as the experimental factors.

At harvest, the researchers measured an extensive suite of traits: shoot and root fresh and dry weights, leaf area with a LI-3100C leaf area meter, leaf greenness via SPAD chlorophyll readings, and leaf gas exchange using a portable LI-6400XT infrared photosynthesis system. From the gas exchange data they calculated net photosynthetic rate, stomatal conductance, transpiration rate, intercellular carbon dioxide concentration, instantaneous water-use efficiency (the ratio of photosynthesis to transpiration), and intrinsic water-use efficiency (the ratio of photosynthesis to stomatal conductance). Data were analyzed separately for each species using two-way analysis of variance, followed by Duncan’s multiple range test where significant effects emerged.

The results were strikingly species-specific. Cherry tomato responded strongly and consistently across multiple traits. The maize-derived MP2025 at 0.1 percent raised water-use efficiency by approximately 31.8 percent relative to the untreated control, an improvement associated with enhanced photosynthetic performance and reduced transpiration rather than any change in stomatal conductance. The microbial-derived AM2025 at 0.05 percent significantly increased net photosynthesis by about 16.5 percent, and leaf greenness rose significantly with MP2025 at 0.1 percent. Leaf area and biomass accumulation also trended upward in tomato, and additional morphological traits including plant height, leaf expansion, and stem diameter improved at the low application rates tested.

Common bean told a different story. Responses were more limited and variable, with fewer statistically significant effects, although the microbial formulation at 0.1 percent increased shoot dry weight by roughly 18 percent, and leaf area rose by about 32.9 percent with AM2025 at 0.05 percent. Notably, in bean the primary benefit appeared to be stomatal rather than photosynthetic: protein hydrolysate application reduced stomatal conductance, thereby raising intrinsic water-use efficiency. The authors interpret this as a water-saving mechanism consistent with drought-adaptive stomatal regulation strategies known in legumes, in contrast to the carbon-gain-driven improvement observed in tomato.

The contrast between the two formulations underscores how much product origin matters. MP2025, derived from maize proteins, and AM2025, derived from yeast, differ in peptide composition, amino acid profiles, and associated bioactive compounds generated during hydrolysis. The study’s strong formulation-by-dose interactions — significant for transpiration and water-use efficiency in tomato, and for leaf area and transpiration in bean — indicate that neither the product nor the dose alone predicts the outcome; only the specific combination does. This aligns with a growing body of evidence that biostimulant efficacy depends on the interplay between source material, hydrolysis process, application strategy, and crop physiology, and that plant responses are not always proportional to the applied dose. Relatively low concentrations of bioactive peptides may be sufficient to trigger signaling and metabolic modulation of nitrogen assimilation and enzyme activity.

The dose dimension proved equally revealing. In tomato, the lower 0.05 percent rate favored photosynthetic stimulation, while the higher 0.1 percent rate favored water-use efficiency, suggesting a dose-dependent shift in the dominant mode of action from carbon assimilation toward water relations. In bean, responses were largely confined to stomatal regulation at the higher concentration. The authors caution that biomass, being a cumulative trait, may lag behind the rapid physiological adjustments that protein hydrolysates induce, and that longer observation periods — ideally spanning the full crop cycle under field or stress conditions — will be needed to determine whether these early physiological gains translate into yield and long-term productivity.

Even with those caveats, the implications are considerable. Demonstrating significant agronomic responses from just two foliar applications at 0.05 to 0.1 percent challenges the assumption that higher rates are necessary, and points toward biostimulant programs that are cheaper, easier to integrate into greenhouse practice, and gentler on the environment. As agriculture confronts the twin pressures of climate change and the environmental costs of synthetic fertilizers — including greenhouse gas emissions and nutrient leaching — tools that improve the efficiency of carbon gain per unit of water lost are increasingly valuable. The Bonn findings make clear that realizing that potential will require tailoring biostimulant choice and dose to the crop in question, but they also demonstrate that these products possess genuine biological activity at rates far lower than the field has generally assumed.

Subject of Research: Effects of low-dose foliar protein hydrolysate biostimulants on growth, physiology, and water-use efficiency of greenhouse tomato and common bean

Article Title: Unraveling effects of foliar protein hydrolysates on growth, physiology and water-use efficiency of greenhouse tomato and common bean

Article References: Bayat, F., Nguyen, T. H., & Gaiser, T. (2026). Unraveling effects of foliar protein hydrolysates on growth, physiology and water-use efficiency of greenhouse tomato and common bean. Discover Agriculture, 4(1), Article 288. https://doi.org/10.1007/s44279-026-00771-5

Image Credits: AI Generated

DOI: 10.1007/s44279-026-00771-5

Keywords: protein hydrolysates, biostimulants, foliar application, tomato, common bean, photosynthesis, water-use efficiency, amino acids, chlorophyll, stomatal conductance, sustainable agriculture, greenhouse crops