Altitudinal Effects on Morphology and Biochemistry of Native Iranian Orchids in Guilan, Iran: Insights into Adaptive Strategies and Conservation Priorities

Climate change is altering temperature and precipitation patterns across elevations, potentially impacting orchid species distribution and survival. This study investigated the physiological and morphological adaptations of four orchid species (Orchis mascula, O. simia, Dactylorhiza romana, and D. lancibracteata) across elevations from 306 m to 2098 m to predict their resilience to changing environmental conditions. Various physiological param and morphological characteristics were measured at 306 m elevation intervals. Results revealed distinct adaptation strategies among the species. O. mascula demonstrated dominance in chlorophyll content, showing 16.0% higher chlorophyll a than O. simia and 28.5% higher than D. romana at 2098 m. Daphne species maintained higher tuber antioxidant levels, with D. romana exhibiting 201% higher content than O. simia at 2098 m. O. mascula and O. simia showed higher tuber phenol content, while D. lancibracteata maintained the highest tuber flavonoid content (31.4% higher than O. mascula at 2098 m). Daphne species also maintained higher glucomannan levels, with D. lancibracteata showing 32.48% content compared to O. mascula’s 23.15% at 2098 m. Morphologically, significant increases were observed with elevation: O. simia’s flower length increased by 69.6%, D. lancibracteata’s tuber length by 167.6%, and D. romana’s leaf count by 596.5% from 306 m to 2098 m. Aerial fresh weight increased for all species at higher elevations, with O. simia showing an 88.0% increase, while aerial dry weight generally decreased. These findings provide valuable insights into orchid species' resilience and adaptability to changing environmental conditions, informing conservation strategies and predicting potential responses to climate change. The study highlights the complex and species-specific nature of plant adaptations to elevation gradients, underscoring the importance of tailored conservation approaches.