Effects Of Potassium On The Storage Property And The Physiological Mechanism Of Kiwifruit

Kiwifruit (Actinidia) is a kind of berry fruit with specific respiratory climacteric, which is sensitive to ethylene, and has low storage-ability. So the development of kiwifruit production is restricted. With the studies on the effects of potassium on physiological function of plant, potassium is playing an increasing role on the studies of kiwifruit storage and keeping fresh. In this paper, the seven-year-old Actinidia deliciosa cv 'Miliang -1' was used as materials to study the effects of pre-harvest K application on kiwifruit storage-ability.The results showed that potassium treatment improved kiwifruit quality and storage-ability. Whose soluble solids content, Vitamin C, starch content and flesh firmness are significantly higher than that of control. However, the highest K treatment with 120g k2o per tree made quality worse. The treatment that applied 80g k2O per tree had the best effect on fruit storage-ability. The amylase activity peak of which was the lowest(9. 38 mg. g-1.15min-1) and POD activity peak of which was the highest(1.91 OD470min-1. g-1. FW). After 73days cold storage, the soften fruit ratio of which was the lowest (15.56%), flesh firmness of which was the highest (0.27MPa),and MDA accumulation of which was the lowest(7. 31 u mol. l-1). By potassium treatment, POD activity peak were significantly increased, amylase activity and MDA accumulation were markedly decreased. Therefore, potassium application delayed fruit senescence and improved fruit storage-ability.We also found that potassium application had quite an effect on mineral content of fruit. The highest K treatment with 120g k2o per tree significantly decreased calcium content of fruit. So storage-ability of fruit was decline. At the 180th day, the quality of kiwifruit which treated with 80g k2O per tree were better than others, and the un-rotten fruit ratio was the highest (68.89%) , all fruit of control had already rotten. It suggestedthat potassium treatment could inhibit disease during cold storage and prolong the storage time of kiwifruit.