The Impact Of Conduit Structure And Transporting Rate On Fruit Quality Of Cara Navel Orange

Cara Cara Navel Orange(Citrus sinensis Osbeck cv. Cara Cara) is the bud mutation of Washington Navel Orange, which was introducted to Huazhong Agricultural University in the 90's from Florida. Now it's the main promoted late-maturing variety in Zigui and its maturation stage is in early December; Its branch's xylem has many patterns. Some shows white and red on each side, some shows either white or red generated from the same base branch, some shows different colors between the upper and lower buds. However the color of their fruit flesh is the same red. Be noted that different types of branches affect the quality of their fruit, many factors affect the fruit quality, the study from the conduit to study the organizational structure.The aim of this paper is to explore the impact of conduit structure and transporting rate on fruit quality of Cara Cara Navel Orange.Fruit conventional qualities include TSS, TA, ascorbic acid and so on, which were mainly measured by common methods. Soluble carbohydrate and organic acids were measured by GC. The microstructure of conducting tissue was observed by paraffin sections and catheter isolation. The differences of the anatomical structure between the two branches were analyzed by measuring the vessel diameter, area ratio and other parameters using a microscope. The sap flow of the two branches was monitored by ICT CropSAP, followed by horizontal and vertical comparative analysis. The main results are as follows:1. The fruits on both white and red branches had no dominant differences in the appearance. We couldn't distinguish them with the unaided eyes. But the fruit flesh and the fruit juice from the red branches were much brighter than the white ones.2. The quality parameters of the fruits on the red branches were less changeable. The fruits had a lower acid content, higher sugar-acid ratio and soluble solid-acid ratio. This showed that the fruits on the red branches had a better taste and overall quality.3. In the aspect of microstructure, the red branches were better than the white ones. In the red branches, the vessels had a larger diameter, more numbers, better structure and covered a larger area. This could be one of the reason that the red branches had a higher transporting rate.4. The transporting rate of the Cara Cara branches was closely related to the environment. The variation trend of the sap flow in the two kinds of branches was almost the same. Under the same condition, the red one had a significantly higher transporting rate than the white one, which led to its better fruit quality.