Heterogeneous light environments induce plasticity in leaf morphology and photosynthesis of two sympodial bamboo species

Introduction Light heterogeneity is common in forest ecosystems. It arises from both horizontal (orientation) and vertical (canopy layer) gradients, driving adaptive strategies in plant morphology and physiology. Methods The responses of leaf morphological and physiological traits in Dendrocalamus farinosus and Bambusa rigida were studied to clarify the adaptative mechanism of these two sympodial bamboo species to heterogeneous light environments. Results and discussion These two bamboo species showed a distinctly higher leaf mass per area (LMA) under high-light environments, with the highest LMA in upper canopy layer of south orientation and the lowest LMA in lower canopy layer of north orientation. Similarly, the maximum net photosynthetic rate (P nmax ) of both bamboo species was significantly higher in high-light environments (south orientation and upper layer) than in low-light environments (north orientation and lower layer). However, the two sympodial bamboo species demonstrated distinct acclimation strategies in leaf morphological and photosynthetic traits: D. farinosus achieved broad acclimation through the stability of its functional traits, whereas B. rigida attained precise acclimation via morphological and physiological plasticity. This study reveals a consistent increase in leaf investment under high light conditions in two sympodial bamboos, alongside species-specific variations in the extent of their morphological and physiological plasticity. These findings provide a theoretical basis for the sustainable management of bamboo forest ecosystems.