Study On The Mechanism Of Early-Senescence In Muskmelon And Its Prevention And Control Technology

Muskmelon (Cucumis melo var. Cantaloupensis) is a highly evolved melon subspecies native to West and Central Asia, the fruit of which is of excellent quality, of rich nutrient, and easy to storage and transportation, known as the queen of fruits. In recent years, as China’s economic development, the improvement of people’s living standards as well as the development of tourism, melon consumer market continues to expand. However, after fruit expansion, muskmelon plants are prone to premature aging, resulting in low yield and fruit quality. Therefore, to ensure the yield and quality of muskmelon fruit, we must find a reasonable and effective method to delay senescence in the post-plant.This study measured physiological and biochemical indicators of leaves undergoing low temperature and leaves vaccinated with gummy stem blight to explore the aging process. Various fertilization techniques were tried to find out the best way to suppress premature senescence, which can provide a theoretical basis and the corresponding measures for muskmelon high quality and high yield cultivation. The main findings are as follows:1As the temperature decreased and low-temperature processing time extended, conductivity of muskmelon increased, as well as SOD activity, POD activity and CAT activity. Cold resistant varieties showed lower conductivity and higher enzyme activity. It can be figured out that under low temperature stress, the membrane system stability of cold resistant varieties was stronger and protective enzymes were of higher activity, which reduced the harm to the cells.2. Gummy stem blight accelerated premature aging. When infected by gummy stem blight pathogen, SOD and CAT activities in leaves rose rapidly, then gradually decreased. POD activity showed a continuing upward trend. SOD and CAT activities of ’summer honey’ were higher than those of ’Jade mushrooms’, while POD activity of ’Jade mushrooms’ was higher than that of ’summer honey’. Chl and Pr contents of ’summer honey’ were higher than those in ’Jade mushroom’, which decreasd in both varieties after inoculation. However,’Summer honey’ declined later, indicating that ’summer honey’ was of stronger resistance to gummy stem blight than ’Jade mushroom’. The leaves by pathogen infection on different nodes showed premature aging degree differences. Leaves of lower nods were influenced adversely by gummy stem blight pathogen and aged too fast.3. Nutrient elements absorption of three muskmelon varieties was confirmed. All three muskmelon varieties absorbed lots of K element. The absorption of N and P showed variety difference. The uptake and accumulation of various elements was different.’Jade mushroom’ and ’summer honey’ were K2O> Ca> N> P2O5> Mg and ’Chui snow No.5’ was K2O> N> Ca> P2O5> Mg.4After fruit expansion, the application of foliar fertilizer can effectively delay premature aging, but the effect was of variety difference. Foliar fertilization can increase soluble Pr and Chl content and reduce the content of MDA. POD activity was significantly reduced, delaying premature aging of the plant.