Research report: Multilevel adaptation strategy of the Cupressus gigantea fine root system between the growing and non-growing seasons

Fine roots of the endangered conifer Cupressus gigantea change their structure, physiology and internal organization between the growing and non-growing seasons, according to a field study that compared absorptive and transport fine roots across three sites. Functional root type significantly affected 22 of 27 measured traits, showing that the two fine-root categories differed across morphological, nutritional, anatomical, physiological and hormonal characteristics. The study found greater structural investment in transport fine roots and stronger physiological, hormonal and mitochondrial responses in absorptive fine roots, with the relative prominence of these traits shifting between seasons.

The researchers sampled roots from Bayi District, Lilong Township and Lang County. Transport fine roots had greater biomass, root volume, root surface area and periderm development, whereas absorptive fine roots had greater specific root length. The local sites also showed distinct patterns.

Bayi District had the highest soil moisture during the growing season and the largest seasonal decline. Lilong Township had the lowest growing-season soil moisture but greater root length, root volume and root surface area during that season, while Lang County displayed broader variation in morphological and anatomical traits. Multivariate analysis showed that the first two principal components explained 54.0% of total trait variation during the growing season and 57.0% during the non-growing season.

During the growing season, dominant trait associations mainly involved fine-root morphology and anatomy, and mitochondria were predominantly elongated and interconnected. In the non-growing season, antioxidant, oxidative, osmotic and hormonal traits became more prominent. Mitochondrial swelling and fragmentation also increased, particularly in absorptive fine roots.

The seasonal pattern therefore extended from external root form and anatomy to physiological regulation and the condition of root-cell mitochondria. Structural equation models showed a good fit and distinct regulatory networks for the two seasonal datasets. Taken together, the results indicate that C. gigantea emphasizes fine-root growth and resource acquisition during the growing season, while the non-growing season is associated with stronger emphasis on antioxidant defense, osmotic adjustment, hormonal regulation and cellular maintenance.

The study identifies this as a multilevel adaptive strategy in which complementary specialization between absorptive and transport fine roots supports fine-root function under seasonal water limitation. Structural development was most evident in transport roots, while the more dynamic physiological and cellular responses were concentrated in absorptive roots. Nevertheless, the study documents coordinated changes across several biological levels: transport roots differed in structural investment, absorptive roots showed stronger physiological and mitochondrial responses, and the traits emphasized by the multivariate analyses changed with the season.

The findings provide a detailed account of how the endangered conifer’s fine-root system differs between growing and non-growing periods while also showing substantial variation among sites.

Subject of Research: Seasonal functional differentiation of absorptive and transport fine roots in giant cypress

Article Title: Multilevel adaptation strategy of the Cupressus gigantea fine root system between the growing and non-growing seasons

Article References: Yang, L., Li, H., Guo, Q., Zheng, W., Li, J., & Duan, H. (2026). Multilevel adaptation strategy of the Cupressus gigantea fine root system between the growing and non-growing seasons. BMC Plant Biology. https://doi.org/10.1186/s12870-026-09835-6

Image Credits: AI Generated

DOI: 10.1186/s12870-026-09835-6

Keywords: Cupressus gigantea, fine roots, root specialization, seasonal adaptation, plant physiology, mitochondria, antioxidant defense, osmotic adjustment, plant hormones, water limitation, Multilevel, adaptation