Effects of Exogenous Melatonin on Kiwifruit Seedlings Growth under Weak Light Treatment

To investigate the effect of exogenous melatonin (MT) on the growth of kiwifruit seedling under weak light treatment, in this study, kiwifruit seedling was used as the experimental material, applied 100 mu mol/L MT solution by root irrigation, and determined physiological indexes under low light intensity. The results provide theoretical basis for improving the yield and quality of kiwifruit. The results showed that the chlorophyll and carotenoid content of kiwifruit leaves increased significantly under weak light treatment, but there was no significant relationship between the application of MT; The content of soluble sugar decreased firstly and then increased, the contents of soluble protein, CAT and POD increased substantially; Root irrigation MT solution can increased the degradation of soluble sugar and CAT, change the trend of soluble protein content and POD. Kiwifruit was called as the 'King of VC', due to its rich nutrition, medicine and VC content. In recent years, agricultural facility has developed rapidly, but the facilities cover and frame structure have a bad effect on light conditions, and spring or autumn seasons often appear cloudy and rainy for several days, which cause plants grow in low light stress. Melatonin (MT) is a small molecule that is widely present in animals, prokaryotes and plants, it has been widely concerned since its discovery in the pineal gland of cattle since 1958 [1]. MT has the ability to scavenge free radicals to protect cells from injury and improve the ability of plants to resist stress in plants, such as resistance to heavy metal stress, anti-aging, salt tolerant, disease resistant, drought resistant, anti UV capacity. In this experiment, one-year-old wild kiwifruit seedling was used as materials, processing from the aspects of photosynthetic pigment content, osmotic adjustment substances and antioxidant enzymes; the function of MT in delaying leaf senescence was analyzed from physiological level, which provided a theoretical basis for the rational use of MT to solve the problem of weak light stress.