Effects of Exogenous Melatonin on Photosynthetic Characteristics of Eggplant Seedlings under Low Temperature and Weak Light Stress

Eggplant cultivar 'Changhong' was subjected to low temperature treatment of 15/10˚C (day/night) in the artificial climate chamber.The effects of exogenous melatonin (MT) on the photosynthetic of leaves under low temperature and weak light stress was investigated.The results showed that with the increasing of melatonin concentration, the net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate(Tr), and light use efficiency (LUE) was enhanced first, and then decreased, the CO 2 concentration of intercellular (Ci) remained relatively stable, and water use efficiency(WUE) showed a downward trend.Thus, melatonin could siganificantly improve the photosynthetic capacity of eggplant under low temperature and weak light stress, and 200 μmol•L -1 was the best concentration.