Response of Photosynthetic Performance in Aronia melanocarpa to Drought Stress and Rehydration

【Objective】The study was to investigate the response of Aronia melanocarpa to soil drought stress. 【Method】 Taking two-year-old A. melanocarpa as the material, man-made simulation of drought stress, and postdrought water treatment were carried out through potted experiments, black fruit glints were studied. Two-year-old plants of A. melanocarpa were subjected to drought stress that simulated artificially. Gradual soil drought stress and subsequent rehydration treatments were carried out through pot experiment, and the effects of soil drought and rehydration on thephotosynthetic characteristics of A. melanocarpa were analyzed.【Result】During the whole process of drought stress, the net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) and transpiration rate (Tr) of A. melanocarpa decreased gradually, however, the water use efficiency (WUE) increased with the aggravation of soil drought stress. Under drought stress, the total chlorophyll content decreased significantly, chlorophyll a/b value increased significantly, and carotenoid content did not change obviously, with higher leaf relative water content (RWC); the CO2 compensation point increased, and the carboxylation efficiency decreased significantly. After 30 days of drought, values of Pn, Gs, Ci and Tr all decreased to the lowest point, which were lower significantly than those before drought stress treatment with 85.4%, 79.86%, 31.98%, and 91.55%, respectively. Meanwhile, the A. Melanocarpa still had certain biological activity and no death occurred. After rehydration, the leaf RWC could be restored to the control level, and Pn, Gs, Ci and Tr all increased rapidly. However, Gs, Ci and Tr could not restore to the level of drought treatment for 3d, but only decreased by 27.99%, 14.15% and 16.58% compared with those under drought treatment for 3d while Pn was 0.54% higher than that of drought treatment 3d, showing strong resilience to adapt to soil drought.【Conclusion】In the course of drought stress, the A. melanocarpa increased its WUE with higher Pn and lower Tr, and maintained good leaf moisture condition to resist the damage caused by drought stress. After the removal of stress, both of leaf RWC and chlorophyll content increased and various photosynthetic parameters recovered. These findings reflected that A. melanocarpa had strong self-regulating capacity after rehydration.