Variations in phytochemistry, morphology, and population structure in Trillium govanianum (Melanthiaceae)

As habitats change, species with higher intraspecific variation have more resources to adapt. Medicinal plants in the Himalayas are increasingly threatened by climate change and other anthropogenic influences. The intraspecific variation within and among 17 populations of the high-elevation herb Trillium govanianum Wall. ex D.Don was studied as an indicator of adaptability. The variation in 19 traits of population structure, morphology, and phytochemistry was assessed across habitats that varied in elevation (2452-3432 m a.s.1.), aspect, latitude (30.1-31.7[degrees]N), and arboreal community. The morphology and population structure were conserved among populations but varied among regions. The populations in the lower elevation mixed forests of Tirthan Valley produced smaller rhizomes but larger plant densities, such that plant biomass per square metre was conserved. The phytochemistry varied among regions and populations within regions, indicating significant variation among habitats. The aboveground morphology of the species masks considerable variations in belowground morphology and phytochemistry. The observed variations can help the species to adapt to the changing environmental conditions by provoking a functional response. Key words: adaptation, anthropogenic pressure, conservation, high-elevation medicinal plant, natural variations. Lorsque les habitats changent, les especes qui presentent une plus grande variation intraspecifique ont davantage de ressources pour s'adapter. Les plantes medicinales de l'Himalaya sont de plus en plus menacees par les changements climatiques et d'autres influences anthropiques. La variation intraspecifique au sein et entre 17 populations de Trillium govanianum Wall. ex D.Don, une herbe de haute altitude, a ete etudiee comme indicateur de l'adaptabilite. La variation de 19 traits de la structure de la population, de la morphologie et de la phytochimie a ete evaluee dans des habitats qui varient en matiere d'altitude (2452-3432 m a.s.1.), d'aspect, de latitude (30, 1 a 31, 7[degrees]N) et de peuplement frodicole. La morphologie et la structure de la population etaient conservees parmi les populations, mais elles variaient selon les regions. Les populations des forets mixtes de basse altitude de la vallee de Tirthan produisaient des rhizomes plus petits, mais des densites de plantes plus importantes, de sorte que la biomasse vegetale par [m.sup.2] etait conservee. La phytochimie variait entre les regions et les populations au sein des regions, indiquant une variation significative entre les habitats. La morphologie aerienne de l'espece masque des variations considerables dans la morphologie souterraine et la phytochimie. Les variations observees peuvent aider les especes a s'adapter aux conditions environnementales changeantes en provoquant une reponse fonctionnelle. [Traduit par la Redaction] Mots-cles : adaptation, pression anthropique, conservation, plante medicinale de haute altitude, variations naturelles.
Introduction The rate at which species adapt to new or changing environments is dependent on their phenotypic plasticity and genetic variation (Fox et al. 2019). Species with a more flexible [...]