Effects Of Potassium Nitrate And Calcium Superphosphate Pre-harvest Spray On Storage Physiology In Red Globe Fruits

The red grape fruit were used to studied through spraying KNO₃ and calcium superphosphate to the ear before harvest.The loss of weight, the rotting rate, the respiration rate, organic acid content and soluble solid content of fruit In the normal-temperature storage conditions and the variation of antioxidant enzymes (POD, PPO, SOD) activity, ROS(O₂^- and H₂O₂) content, AsA, MDA, total phenol and flavonoid content in the low-temperature storage conditions were investigated, which provide a theoretical basis on the application of KNO₃ and calcium superphos- phate for cultivation of the red grape.The results were as follows.(1)The red grape ear was treated using KNO₃ and calcium superphosphate before harvest, the lost of fruit-water was reduced effectively and the decline of organic acid content was inhibited during storage ,the rotting rate of the fruit was reduced and the lower respiratory rate of the fruit,0.5% and 3% of KNO₃ and calcium superphosphate of which was the best. However, all of the treatment had no significant effect on soluble solid content of fruit.(2)KNO₃ and calcium superphosphate were used to the ear before harvest, which inhibited the accumulation of O₂^-and H₂O₂ during storage and reduced activity of POD, PPO and SOD of fruit. Thus, to a certain extent, reduced damage of ROS to the fruit during storage and delayed the fruit decay .(3)The red grape ear was treated using KNO₃ and calcium superphosphate before harvest, which had no significant effect on total phenol and flavonoid content of fruit during storage.(4)KNO₃ and calcium superphosphate were sprayed on the red grape ear before harvest , MDA content of fruit was reduced effectively during storage and reduced by 20.7% and 25.4% compared with the fruit which was not sprayed KNO₃ and calcium superphosphate. Moreover, the using of calcium superphosphate can improved the AsA content of fruit and delayed its downward trend, but KNO₃ had no significant effect on the content of AsA of fruit .In addition, comparing the effect of calcium superphosphate with KNO₃, there was the conclusion that the using of calcium superphosphate can better inhibited POD, PPO and SOD activity obviously , reduced O₂^-and H₂O₂ content ,improved AsA and total phenol content of the red grape fruit.