Elevational adaptation and phenotypic plasticity of Codonopsis clematidea in the trans-Himalaya

The process of adapting to changing environmental conditions plays a pivotal role in driving plant diversification. Elevational gradients provide a unique opportunity to investigate adaptation to diverse climatic conditions. Codonopsis clematidea is an important medicinal plant found across various habitats at different elevations in the Trans-Himalayan region. The goal of this study was to evaluate its morphological adaptation across four elevational ranges: Damsna (3206 m asl), Hagnis (3500 m asl), Sapi (3877 m asl), and Drass (4010 m asl) in Ladakh, India. The findings indicate that higher elevations (Drass, 4010 m asl) result in reduced plant height and leaf dimensions, whereas lower elevations (Damsna, 3206 m asl) promote greater vegetative growth and reproductive output. Root length increases with elevation, suggesting an adaptive mechanism for enhanced nutrient and water acquisition in alpine environments. Regression analysis revealed a significant negative correlation between plant height and elevation, while root length showed a positive association. Principal Component Analysis (PCA) identified mid-altitude populations (Hagnis, 3500 m asl) as optimal for enhanced vegetative growth, highlighting the role of phenotypic plasticity in elevation-driven selection. Lower elevations favored reproductive investment, while higher elevations induced structural modifications for survival, indicating trade-offs between growth and adaptation. These findings provide a scientific basis for prioritizing mid-altitude regions (3200–3500 m asl) for sustainable cultivation and conservation efforts, contributing to a better understanding of high-altitude plant adaptation.