Studr On The Physiological Reason And Preventive Regulation Of Fruit Granulation In Cara Cara And Lane Late Navel Orange

Granulation is an important factor influencing the fruit quality of citrus fruits, so it is very urgent to study on the reasonand and preventive measures of citrus.The effect on the granulation and quality of fruit were studied with Citrus sinensis Osbeck cv. Cara cara navel orange and Citrus sinensis Osbeck cv. Lane late during storage of fruit kept on tree. The main results were as follows:1. The relationship between fruit granulation and fruit qualityThe fruit granulation was mainly affected by the content of fruit actric acid and Vitamin C for Cara cara navel orange, and was mainly affected by the content of fruit actric acid for Lane late navel orange. It is presumed that the decrease of fruit actric acid and Vitamin C is an important factor to cause fruit granulation to happen.2. The relationship between fruit granulation and mineral elementThe changes and correlation of fruit quality and the content mineral nutrient elements in pericarp and flesh in Cara cara navel orange and Lane late navel orange were studied, we deemed preliminaryly that not only the increase of flesh N, K, Cu content and pericarp N, P, K, Fe,Cu content,but also the decrease of flesh P, Ca,Fe, Zn content and pericarp Ca,Zn content reduced the content of fruit citric acid and Vitamin C, which caused fruit granulation to happen.Leaf P content was positively negatively correlated with the fruit granulation index at the 0.01 level in Cara cara navel orange, and was negatively correlated with the content of fruit cirtic acid and Vitamin C, so it is showed that leaf P may affect the occurrence of fruit granulation by directly changing fruit citirc acid and Vitamin C.Available K were deficient, and available Cu was excess in soil, The granulation index in Citrus sinensis Osbeck cv. Cara cara navel orange was significantly positive with available K content in soil, and and negatively relative with available Cu in soil, which suggested that deficient and excessive soil content cause fruit granulation to happen.3. The effect on the granulation of fruit under different fertilizer treatments.As the on-tree storage time increased, the changes of fruit granulation index under different fertilization treatments was increased, but the content of fruit citric acid and Vitamin C was decreased. In the on-tree storage stage, the granulation index of fruit in the compound fertilizer+N fertilizer and compound fertilizer +P fertilizer were significantly higher than that of the control, respectively increased by 30.4%～57.9% and 28.6%～50.9%, the granulation index of fruit in compound fertilizer+K fertilizer was decreased by13.0%～20.0%, but was not significantly different compared with the control. Most of fruit quality index were almost not influenced by compound fertilizer+N fertilizer and compound fertilizer+P fertilizer, but they had a greater influence on the content of fruit citirc acid and Vitamin C, both of us were significantly different from the control, decreased by 6.7%～19.5%and 9.9%～16.1%, but compound fertilizer+K fertilizer had no an apparent influence on fruit quality. So we can reduce nitrogen fertilizer and add K fertilizer to control the incidence of fruit granulation.4. The effect on the granulation index and quality of fruit for different fruit size.As the on-tree storage time increased, the changes of fruit granulation index under different fruit size was increased, and there were significant differences in the fruit granulation index between different fruit size. The fruit granulation index of SD80-85 mm is higher than that of SD70-75 mm, the fruit granulation index of SD70-75 mm is higher than SD60-70 mm. In the reasearch, the fruit quality for different size was analysised, the result showed: there were extremely significant positive correlation between fruit suture diameter, polar diameter, peel thickness, juice yield, TSS-acid ratio and fruit size, and significant negative correlation was found between fruit citric acid, Vitamin C and fruit size. So, befor fruit kept on the tree, we can pick down the big fruit and retain medium fruit and small fruit to control the incidence of fruit granulation.