Morphological changes and physiological responses of Lycoris radiata leaves under high temperature treatment

<bold>Objective</bold> This study aims to investigate the morphological changes and physiological responses of <italic>Lycoris radiata</italic>（L’Herit.）Herb. under high-temperature stress，and preliminarily elucidate the mechanisms underlying high-temperature-induced dormancy，thus providing a scientific basis for stress-resistant cultivation and further research on the summer dormancy mechanisms of this species. <bold>Method</bold> Using ambient temperature（day/night：25 ℃/20 ℃）as the control（CK），leaf morphology and related physiological parameters were compared under two high-temperature treatments：A（37 ℃/30 ℃）and B（40 ℃/33 ℃）. <bold>Result</bold> （1）Under room temperature treatment，the phenomenon of “leaf tip yellowing and withering” first appeared on the 20th day，while the complete leaf senescence did not occur.In contrast，under treatments 37 ℃/30 ℃ and 40 ℃/33 ℃ leaf tip yellowing appeared as early as day 7 and day 1，respectively，and complete leaf senescence occurred by day 21 and day 18，respectively.（2）With increasing temperature，relative water content（RWC），total chlorophyll，soluble sugar，and soluble protein content in leaves showed a declining trend，while the content of superoxide anion（O₂·⁻）and peroxidase（POD）activity increased significantly.Activities of superoxide dismutase（SOD） and catalase（CAT）displayed a “rise-then-fall” pattern. <bold>Conclusion</bold> High-temperature stress significantly influences the leaf growth and physiological metabolism of <italic>L. radiata</italic>，as evidenced by accelerated leaf senescence，increased water loss，elevated reactive oxygen species（ROS）levels，and marked reductions in chlorophyll，soluble sugars，and soluble proteins.Although <italic>L. radiata</italic> can mitigate oxidative damage to some extent by enhancing antioxidant enzyme activities and modulating ROS levels，its self-regulation capacity remains limited.