Study On The Plant Endogenous Hormones And Physiological-Biochemical Mechanism Of Citrus During Storage

The citrus is a member of Citrus Linn of Rutaceae. The fruits of citrus are delicious, rich in nutrient and can be eaten raw, which also can be processed into kinds of production including juice. The citrus plants are high and stable yield, so they can create high economic values, which have become one of the most important fruit trees in the south of China. They play a significant role in developing rural economy.In recent years, with the fruits ripening on the physiology of the in-depth, people recognize that the fruits ripening are controlled by genes. Hormone gene may be the expression of ripening for initiation factor, and the application of plant growth regulators is an effective means of controlled fruits ripening. Many studies show that in the five kinds of plant hormones, not only ETH, but also ABA, GA, IAA and CTK are affected the ripening in different ways. The citrus fruits Granulation, a physiological disease widely appeared in citrus fruits ripeness and storage process. This disease in citrus fruits is especially common in sweet orange and mandarin which can greatly decrease the commodity value of citrus fruits products such as a significant reduction in nutrients and juice, less sweet and color flavor reduction, poor quality and so on. The citrus fruits Granulation are not only the major limiting factor of fruit quality but also the important factor affecting on the further development of China's citrus industry. This paper is studied on the relationship between four varieties of citrus fruits physiological and biochemical characteristics and granulation, and the relationship between plant hormones and granulation.This research had carried out in the Storage and Process Laboratory of Citrus Research Institute, Chinese Academy of Agricultural Sciences, between the years of 2008-2010. In this text, the change of endogenous hormones(GA, IAA and ABA) contents he oranges, Satsuma Mandarin, Ponkan and Jincheng447 during storage were studied by high performance liquid chromatography(HPLC); The change of Sugar, Organic Acids, Vitamin C and Respiration during citrus fruits storaging; The comparison of GA, IAA and ABA between normal fruits and granulation fruits during citrus fruits storaging; The comparison of Sugar, Sugar, Organic Acids, Vitamin C and Respiration between the normal fruits and granulation fruits during citrus fruits storaging. To reveal the endogenous hormones on the storage mechanism of regulation of fruits ripening, show the relationship between endogenous hormones, nutrients contents and granulation, provide a scientific theoretical basis for the fruits storage measures. The main results are as follows: 1. Gibberellin (GA3) is a type of fruits ripening inhibition of plant growth hormones. The content of the fruits during storage shows the trend of decreasing. Compared with the high level of GA3 during growth and development, plummeted to a low level of postharvest fruits ripening is a necessary condition. The GA3 contents between normal fruits and granulation fruits were significantly (P<0.05).2. Auxin (IAA) is a king of growth hormone, aging on the ripening inhibited. In the ripening process, IAA contents continued to decline, until the lowest level, However, after ripened, there is another rising process. The IAA contents between normal fruits and granulation fruits were significantly (P<0.05).3. Abscisic acid (ABA), there is a clear reduction process in the later period of fruits growth. In the subsequent ripening process of aging, ABA has a cumulative process, finally a peak, and reducing slowly. The symptoms of granulation are mainly in pulp. The experiments show that the ABA content in the granulation fruits pulp was increased, and there was close contact between them.4. Sugar is one of important indicators of testing the citrus fruits qualities. Tests show that the four varieties of citrus fruits during storage, the total sugar contents in general show decreased. The total sugar contents between normal fruits and granulation fruits were significantly (P<0.05).5. The reduction of organic acids contents during storage one of important indicators showing the citrus qualities changed. The texts of the four varieties citrus fruits during storage show that organic acids contents in general were reduced. As maturity is not the same time when picking, organic acid content of the Ponkan fruits in the early storage has increased, but at last reduced. The organic acids contents between normal fruits and granulation fruits were significantly (P<0.05).6. The tests show that the vitamin C contents of four varieties citrus during storage, with the changes of sugar and water it will appear reduced and increased, but the overall contents of vitamin C in the storage time were reduction trend.7. Respiration rate is one of the main factors affecting the fruits granulation. As the respiration rates increase, and speed up the sugar and acid consumption, cause the fruits granulation. The texts show that the fruits respiratory rates of 4 kinds of citrus had a significant positive correlation with fruit index of granulation. The respiratory rates contents between normal fruits and granulation fruits were significantly (P<0.05).