The research, conducted by Jacopo Franzoni, Dania Cruz-Tejada, Angelino Carta and Lorenzo Peruzzi of the University of Pisa for the first species, and by Franzoni, Antonio Giacò and Peruzzi for the second, forms part of an ongoing series documenting chromosome numbers for the Italian flora. Italy is one of Europe’s richest countries for plant diversity, yet the chromosome counts of many of its species rest on old literature, ambiguous records, or no data at all. Each verified count is a data point that feeds into larger questions about how plants evolve, diversify, and sometimes vanish.

The first target, Crepis suffreniana, is a small annual in the sunflower family with a strikingly fragmented distribution. It occurs in three main areas: the maritime regions of south-western France, parts of south-eastern France, and a single Italian population confined to the Migliarino-San Rossore-Massaciuccoli Regional Park in Tuscany, near Pisa. That Italian population is the species’ entire national foothold, which makes every biological detail about it matter for conservation. The researchers obtained seeds, germinated them, and examined the dividing cells of young root tips—standard practice in plant cytogenetics, because root tips are where cell division is abundant and chromosomes are easiest to observe.

The laboratory protocol is a beautifully tuned routine. Root tips were pre-treated with 0.4% colchicine for three hours, a chemical that halts cell division at metaphase, when chromosomes are most condensed and countable. The tips were then fixed in Carnoy solution, a mixture that preserves cellular architecture, hydrolysed in 1 normal hydrochloric acid at 60 degrees Celsius to soften the tissue, and finally stained with leuco-basic fuchsine, a dye that renders chromosomes a deep, unmistakable purple. Squash preparations—literally flattening the stained tip onto a slide—spread the chromosomes into a single optical plane where they can be tallied one by one.

The verdict for the Tuscan plants: 2n = 8, meaning eight chromosomes in the somatic cells. That number agrees with the classic account published by the great Crepis specialist Babcock in 1947, but it carries a crucial new significance. Babcock never specified whether his original count came from French or Italian material, leaving the Italian population’s cytology undocumented for nearly eight decades. The genus Crepis is famous among cytologists for its chromosomal diversity: within the section Phytodesia, which includes C. suffreniana, eight out of ten species share 2n = 8, while two relatives, C. capillaris and C. fuliginosa, dip to 2n = 6. The new count confirms the Tuscan population sits squarely within the standard pattern of its group, yet it is the first count ever formally documented from Italian plants of this species.

The second result is the one that made botanists sit up. Dianthus furcatus subsp. furcatus, a Mediterranean mountain plant or orophyte of the western Alps, was previously reported in the literature as tetraploid, with 2n = 60 chromosomes—records dating back to Darlington and Wylie’s landmark chromosome atlas of 1956 and Carolin’s work the following year. Those old citations referred generically to Italy and the Alps, without pinpointing populations. When the team counted chromosomes from plants collected on the southern slope of Monte Frontè in Liguria, at an altitude of 1,668 metres among grasslands with protruding rocks, they found a number nobody expected: 2n = 90.

Ninety chromosomes corresponds to a hexaploid level—six complete sets of the basic genome—in this genus, a level not previously documented for the species. Polyploidy, the possession of multiple whole genome copies, is one of the dominant forces in plant evolution, and discovering which ploidy level a population carries can reshape how scientists draw species boundaries, reconstruct migration histories, and design conservation strategies. The hexaploid finding contrasts sharply with previous studies of D. furcatus in the broad sense from the Italian Alps, which had documented only the diploid level, and with the tetraploid reports inherited from mid-twentieth-century compendia. The Corsican endemic D. gyspergerae, considered by some authors a subspecies of D. furcatus, is reported as diploid, further enriching the picture of chromosomal variation across this tangled species complex.

The Italian populations of D. furcatus are organized into three subspecies: the typical form spanning the western Alps, D. furcatus subsp. dissimilis known only from Vallone degli Alberghi in the Maritime Alps of Piedmont, and D. furcatus subsp. lereschii in the Graian Alps. A hexaploid count in the typical subspecies now raises tantalizing questions. Are the populations of subsp. furcatus uniformly hexaploid, or do ploidy levels vary across the Alpine arc? Could older tetraploid records have been based on misidentified material, or on populations that have since been reinterpreted taxonomically? Answering those questions will require the kind of population-by-population sampling this study exemplifies, and it may ultimately require genome size measurements and molecular markers to trace how the polyploid lineages arose and spread.

What makes these two counts compelling beyond specialist circles is the contrast they present. One species shows textbook stability: its eight chromosomes match an eighty-year-old expectation, and the interest lies in finally pinning the record to the plant’s most vulnerable Italian stronghold. The other shows textbook revision: a number enshrined in reference works since the 1950s dissolves on contact with fresh material from a specific Ligurian mountain. Both outcomes are essential. Verified chromosome numbers underpin karyological databases, inform cytotaxonomic treatments of difficult groups, and provide baselines for detecting hybrids and polyploid ecotypes that standard morphology can miss.

The work also highlights the quiet infrastructure of biodiversity science. Each count is anchored to a voucher specimen—catalogued and preserved in the herbarium of the University of Pisa—collected at a precisely recorded location and date, so that any future researcher can retrace the evidence. The Pisa group actively invites contributions of new chromosome data, with submissions directed to Antonio Giacò and required to include voucher details and methods. In an era when genome sequencing grabs headlines, the humble squash preparation of a root tip continues to deliver results that no database can substitute: a direct, physical count of the hereditary units of a living plant. For Crepis suffreniana and Dianthus furcatus subsp. furcatus, those counts now exist on firm ground, and the Italian flora’s genetic atlas is one step closer to complete.

Subject of Research: Chromosome counts of two native Italian plant species, Crepis suffreniana and Dianthus furcatus subsp. furcatus

Article Title: Chromosome numbers for the Italian flora: 18

Article References: Franzoni, J., Cruz-Tejada, D., Carta, A., Giacò, A., & Peruzzi, L. (2026). Chromosome numbers for the Italian flora: 18. Italian Botanist, 21, 233-236. https://doi.org/10.3897/italianbotanist.21.200391

Image Credits: AI Generated

DOI: 10.3897/italianbotanist.21.200391

Keywords: cytogenetics, chromosome numbers, Italian flora, Crepis suffreniana, Dianthus furcatus, polyploidy, hexaploid, plant taxonomy, conservation botany, western Alps, Tuscany, Italian Botanist

The scale of the achievement is considerable. The team assembled a genome of 11.98 gigabases, one of the larger plant genomes sequenced to this level of quality, and organized it into 114 pseudochromosomes. That number alone tells a story: rather than the simple paired chromosomes of most familiar organisms, M. wufengensis is a hexaploid, carrying six complete sets of chromosomes. Resolving such a genome is a formidable technical challenge, because the six copies of each chromosome are similar enough to confuse assembly algorithms but different enough to matter biologically. The researchers overcame this by using high-fidelity long-read sequencing combined with chromatin conformation capture, producing what is known as a haplotype-resolved assembly, in which each of the six chromosome sets is reconstructed separately rather than collapsed into a single blended sequence.

Quality control metrics reported with the assembly suggest it meets the standards now expected of flagship plant genomes. The team verified genome size independently by flow cytometry, confirmed the karyotype, and assessed completeness using BUSCO analysis for both the haploid and the full hexaploid representations. A high long terminal repeat index indicates that the repetitive elements that litter large plant genomes were correctly resolved rather than fragmented. These details matter because a genome that is incomplete or misassembled can mislead every downstream analysis, from gene annotation to evolutionary inference. With this foundation in place, the researchers could begin asking the questions that make the genome scientifically valuable.

One of the most intriguing findings concerns the timing of the hexaploid event. Genome duplication analysis indicates that the whole-genome multiplication that made M. wufengensis hexaploid occurred approximately 6.8 million years ago, and, notably, after the species had already diverged from its closest relative, M. sieboldii. This ordering is significant for evolutionary biology. It means the polyploidy is not an ancient event shared across the lineage but a relatively recent innovation specific to this branch, one that may have shaped the species’ unique characteristics. Polyploidy is a major force in plant evolution, often associated with increased vigor, ecological flexibility, and the ability to colonize challenging environments, and dating these events precisely helps reconstruct how plant diversity has been generated.

Gene family analysis added another layer to the story. The researchers identified genes that are specific to M. wufengensis or expanded in number compared with related species, and their functions point to adaptations that could help explain the tree’s survival strategy. Enriched categories include genes involved in ultraviolet tolerance, chromosome maintenance, and cell regeneration. For a tree whose mountain habitat exposes it to intense high-altitude sunlight, enhanced ultraviolet tolerance is an intuitively plausible advantage. Expanded chromosome maintenance machinery may also reflect the cellular demands of managing a massive six-copy genome, in which DNA repair and segregation must operate reliably across 114 chromosomes in every dividing cell.

The red flowers that make the species famous were the next target. By combining gene expression profiling with metabolite assays across flowers of three different colors, the team narrowed the chemical basis of pigmentation to four anthocyanin-related compounds. Anthocyanins are the water-soluble pigments responsible for red, purple, and blue hues across the plant kingdom, and their exact chemical modifications determine the precise shade a petal displays. Among the candidate compounds identified were cyanidin-3-O-rutinoside, peonidin-3-O-glucoside, peonidin-3-O-(caffeoyl) rhamnoside, and a more elaborate delphinidin derivative, delphinidin-3-O-(6”-O-coumaroyl) rhamnoside-5-O-galactoside. Together, these four molecules emerged as the key determinants of flower color in the species.

To find the enzyme that builds them, the researchers turned to a gene annotated as Mwu49047, which encodes an anthocyanin UDP-glycosyltransferase, an enzyme family that decorates anthocyanin backbones with sugar groups, stabilizing the pigment and tuning its color. Enzyme assays revealed that Mwu49047 is unusually versatile: it accepts both cyanidin and delphinidin as substrates, two anthocyanin types that normally require distinct enzymes, yet it acts with strict regiospecificity, attaching sugars exclusively at the 3-OH position of the molecule. This combination of substrate promiscuity and positional precision is a fascinating enzymatic property, suggesting that a single gene could contribute to multiple pigment pathways simultaneously, a possible evolutionary shortcut in the construction of the species’ distinctive palette.

Fragrance proved to be an equally tractable puzzle. By measuring volatile metabolites across four different tissues and integrating the results with gene expression data, the team identified the major components of the floral scent as cis-farnesene, (E)-2-octenal, and nonanal. Farnesene is a sesquiterpene common in the perfumes of many flowers and fruits, while the two aldehydes contribute green, waxy notes characteristic of fresh floral bouquets. Using co-expression network analysis, the researchers went further and pinpointed a specific co-expression module whose member genes are implicated as regulators of the two aldehydes, providing a starting point for understanding how the tree coordinates the emission of its scent compounds.

The practical implications extend well beyond curiosity. M. wufengensis is a recently discovered species with significant ecological and ornamental value, and the lack of genomic resources had been a genuine obstacle to both its conservation and its use in horticulture. A reference genome of this quality enables breeders to trace the genes underlying flower color and fragrance through crossing programs, allows conservation geneticists to assess diversity across wild populations, and gives evolutionary biologists a new reference point for studying polyploidy in one of the world’s most ancient flowering plant families. Magnolias occupied the forests of the age of dinosaurs, pollinated by beetles before bees existed, and every high-quality genome from this lineage adds a page to the record of how flowering plants came to dominate the planet.

The study also demonstrates how far plant genomics has moved in a few years. Assembling an 11.98-gigabase hexaploid genome with each haplotype resolved would have been near-impossible a decade ago; today it is achievable by a team combining university laboratories with a local biotechnology company, supported by provincial and national funding programs in China. The work, led by researchers at Hubei University of Chinese Medicine together with colleagues at Huazhong Agricultural University and partners in Wufeng County, was conducted with permission from the local forestry administration and in compliance with national regulations for sampling. As sequencing technology continues to fall in cost, genomes of this caliber can be expected for an increasing share of the world’s rare and charismatic plants, many of which, like the red-flowered magnolia of Wufeng, hold their secrets in six copies of every chromosome.

Subject of Research: Haplotype-resolved genome assembly and flower color and fragrance biosynthesis in the hexaploid Magnolia wufengensis

Article Title: The haplotype-resolved, chromosome-scale genome assembly of the hexaploid Magnolia wufengensis provides valuable insights into genome evolution and the biosynthesis genes for flower color and fragrance

Article References: Du, Z., Zhang, M., Xu, L., Wang, X., Yao, Y., Liu, J., Chen, C., Meng, Y., Ye, L., Wang, N., & Shi, Z. (2026). The haplotype-resolved, chromosome-scale genome assembly of the hexaploid Magnolia wufengensis provides valuable insights into genome evolution and the biosynthesis genes for flower color and fragrance. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10057-z

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10057-z

Keywords: Magnolia wufengensis, genome assembly, hexaploid, haplotype-resolved, anthocyanin, flower color, floral fragrance, UDP-glycosyltransferase, polyploidy, plant genomics, volatile compounds, BMC Plant Biology

The BBCH scale, developed originally by Germany’s Biologische Bundesanstalt, Bundessortenamt and chemical industry, provides a universal decimal coding system for describing plant development, from BBCH 000 (the dry seed) through BBCH 907 (a fully desiccated, dead plant). While the system has been applied to countless crops and to related chenopods such as quinoa and the Taiwanese supergrain djulis, no comprehensive framework had ever been established for C. album itself. That gap mattered, because the species occupies a peculiar dual position in agroecosystems: its young shoots deliver vitamins A, C and K, iron, calcium and protein to rural diets, while mature plants compete aggressively with wheat, mustard and barley, host plant pathogens and insect vectors, and replenish soil seed banks with tens of thousands of seeds per plant.

To build the framework, the research team, led by Reena Rathore and Dipti Bisarya of Lovely Professional University in Punjab, worked with two naturally occurring seasonal populations that differ not only in phenology but in chromosome number. The winter population, a hexaploid with 2n = 54 chromosomes, dominates Rabi crops in northern India between November and March and is characterized by broadly ovate leaves, a semi-dwarf stature and a short-day flowering response. The summer population, a tetraploid with 2n = 36 chromosomes, occupies wastelands and field margins from April to September, growing taller with lanceolate leaves and a long-day response. Ploidy levels were confirmed through chromosome counts of root tip meristems and floral buds, supplemented by measurements of stomatal size and density, and voucher specimens were deposited in the Botanical Survey of India herbarium.

Field trials were conducted at the university’s research farm in Phagwara, Punjab, in a subtropical climate with sandy loam soil of pH 7.9. The winter population was sown on 6 November 2023 and grown until 25 March 2024; the summer population ran from 18 April to 29 September 2024. Each population was established in three replicate plots with irrigation supplied as needed but fertilizers, herbicides and pesticides deliberately withheld to maintain near-natural conditions. Tagged plants were observed daily throughout both seasons, with developmental timing expressed in days after sowing, plant height measured at representative stages, and thermal accumulation calculated as growing degree days using a base temperature of 5 °C and an upper threshold of 45 °C.

The results exposed a striking seasonal divergence in developmental strategy. During the vegetative phase, the summer population was the clear front-runner. Cotyledons unfolded at 12.0 days after sowing compared with 16.5 days in the winter population, the first true leaves appeared nearly a week earlier, and nine or more leaves had developed by day 22.0 versus day 30.7. Branching told the same story: the first side shoot emerged at 25.5 days in summer plants against 35.4 days in winter plants, and stem elongation began at 45.7 versus 51.7 days. By the time winter plants had completed stem elongation at 78.1 days, the summer cohort had already finished the same stage twelve days earlier. Virtually every vegetative milestone was statistically significantly advanced in the summer population.

Then the tables turned. The moment the plants shifted from building bodies to making seeds, the winter population surged ahead. Inflorescence initiation occurred at 63.1 days after sowing in the winter cohort, a full thirty days before the summer population reached the same stage at 93.6 days. First flowers opened at 72.0 days in winter plants compared with 114.0 days in summer plants, and the entire flowering sequence, fruit development, fruit maturation and senescence followed in the same pattern, with every reproductive milestone significantly earlier in the winter population. Whole-plant death arrived at 140 days for the winter cohort and 164 days for the summer cohort. The winter plants, in effect, compressed their reproductive schedules to beat the approaching heat of spring, while summer plants lingered vegetatively much longer before committing to reproduction.

Thermal-time analysis added a deeper dimension to the story. Although the summer population reached vegetative stages sooner in calendar days, it required vastly more accumulated heat to finish its life cycle: 4261.18 growing degree days compared with just 1301.82 for the winter population. That enormous thermal budget reflected the summer cohort’s prolonged vegetative growth, delayed reproduction and greater final stature. Plant height itself diverged dramatically, with summer plants reaching a maximum of 226 centimetres against only 81 centimetres for their winter counterparts. In both populations, height increase was essentially complete by flowering, after which growth was redirected toward seed production, indicating that stem elongation is strategically front-loaded before the reproductive phase claims the plant’s resources.

The authors are careful about interpretation. Because each cytotype was grown during its natural season, temperature, photoperiod and other environmental variables were inherently confounded with chromosome number, so the observed differences represent phenological variation between seasonal cytotypic populations rather than proof that ploidy alone dictates developmental behaviour. The timing patterns nonetheless align well with known environmental regulation of flowering, in which temperature and photoperiod cues govern developmental transitions in annual plants. Higher summer temperatures plausibly accelerated vegetative growth, while the winter population’s rapid reproductive transition is consistent with short-day, cool-season flowering responses documented in the species since the classic photoperiod studies of Ramakrishnan and Kapoor in the 1970s.

Beyond its scientific value, the framework carries immediate practical weight. By coupling standardized BBCH staging with accumulated thermal time, farmers and researchers can predict when weed populations will germinate, flower and set seed, allowing herbicide applications, mechanical control and scouting operations to be synchronized with biologically vulnerable stages rather than fixed calendar dates. The team also mapped stage-specific ecological functions and risk windows across the life cycle: seedlings and young plants can serve as reservoirs for soil-borne pathogens and nematodes, dense flowering canopies create microclimates favourable for downy mildew caused by Peronospora variabilis, reproductive tissues support pollinators while facilitating vector-borne virus transmission, and senescent residues can harbour fungal inoculum and nematodes that carry over between cropping seasons.

The standardized coding also opens the door to precision agriculture technologies, including remote sensing, drone-based monitoring and automated growth-stage identification, all of which depend on objective, transferable developmental reference points. The authors caution that the study covered a single location and one growing season per population, so the framework should be validated across multiple years and climates, and common-garden experiments will be needed to disentangle cytotype effects from environmental plasticity. Still, the achievement stands: a plant that has both fed and frustrated humanity for millennia finally has a complete, reproducible developmental language, one that promises to sharpen everything from weed management to comparative phenology in a warming world where the seasonal rhythms of aggressive weeds will increasingly determine who wins the contest for the field.

Subject of Research: Phenological staging of seasonal hexaploid and tetraploid populations of the weed and vegetable species Chenopodium album using the extended BBCH scale

Article Title: Phenological documentation of two seasonal cytotypic populations of Chenopodium album L. using extended BBCH scale

Article References: Rathore, R., Kumar, V., Shankhwar, A. K., Faizan, M., Alam, P., Manzar, N., & Bisarya, D. (2026). Phenological documentation of two seasonal cytotypic populations of Chenopodium album L. using extended BBCH scale. Discover Plants, 3(1), Article 391. https://doi.org/10.1007/s44372-026-00861-0

Image Credits: AI Generated

DOI: 10.1007/s44372-026-00861-0

Keywords: Chenopodium album, BBCH scale, phenology, cytotypes, hexaploid, tetraploid, weed ecology, growing degree days, seasonal populations, weed management, plant development, agroecosystems