Leaf Anatomical Structure and Photosynthetic Physiology Responses of Sorbus folgneri Seedlings under Drought Stress

Four levels of drought stress were applied to 1-year-old potted seedlings of Sorbus folgneri to investigate the effects of drought on leaf anatomical structure and photosynthetic characteristics.The results showed that:(1)Drought stress had induced significant reduction in leaf thickness,caused higher palisade to spongy ratio in light and moderate,lower ratio in severe stress.(2)Drought depressed synthesis of photosynthetic pigments,reduced the tissue concentrations of chlorophylls and carotenoids,caused higher chlorophyll a to b and chlorophyll to carotenoids ratio.(3)The diurnal variation of net photosynthetic rate,transpiration rate,stomatal conductance decreased,but intercellular CO2 density increased with drought stress increasing.The limitation of photosynthesis was mainly caused by non-stomatal factors.In summary,S.folgneri demonstrated to be drought-resistant,it could adjust its leaf anatomical structure and net photosynthetic capacity according to levels of drought stress to maintain survival and growth.