Study On The Rules Of Coloring And Sugar Accumulation In Cara Cara Navel Orange (C. Sinensis Osbeck Cv. Cara Cara Navel Orange)

Sugar in the fruit is not only the matter which affects fruit sweetness, but also the elementary material of the synthesis of acid, carotenoid, some endogenous hormone, other nutritional composition and aroma substance. Furthermore, it puts an importance role on the forming of fruit quality. On the one hand, carotenoid including lycopene and beta-carotene, endogenous hormone (such as GA3 and ABA) all come from glucose which is the direct production of photosynthesis via plant isoprenoid approach, on the other hand, the accumulation of sugar and biosynthesis of carotenoid are regulated by endogenous hormone. The composing and concentration of carotenoid not only connect the color and luster of fruit appearance and juice, but also involve the nutrition and health protection of citrus fruit and are important index deciding the quality of citrus fruit. In the present work, the fruit coloring and sugar accumulation rules in Cara Cara Navel orange (C. sinensis Osbeck cv. Cara Cara Navel orange) which grafted on Trifoliate(Poncirus trifoliata Raf) as rootstock and Robertson Navel orange(C. sinensis Osbeck cv. Robertson)as interstocks were studied. The main results are reported as follows. 1. Coloring rule during fruit development in Cara Cara Navel orange1.1 Changes of lycopene and beta-carotene concentration during fruit development in flesh of Cara Cara Navel orange Lycopene and beta-carotene concentration increased along with fruit development. Lycopene accumulated slowly during early period of fruit development and increased quickly before fruit coloring and decreased or increased slightly during fruit coloring, then increased slowly during fruit maturation. The synthesis of beta-carotene lagged to lycopene, which accumulated slowly before fruit coloring and increased quickly during fruit coloring and increased quickly or decreased slightly during fruit maturation. Their concentration existed very significantly positive correlation, which indicated that their accumulation in fruit was simultaneous.1.2 Changes of chlorophyll and carotenoid concentration during fruit development in peel of Cara Cara Navel orange Chlorophyll concentration in peel maintained higher level during early and expanding period of fruit development and decreased quickly during fruit coloring and approached 0 during fruit maturation. Carotenoid in peel had certain concentration during early period of fruit development and changed unremakable during fruit development and decreased slowly before fruit coloring, then increased from fruit coloring to maturation and reached maximum at fruit maturation. Before and during fruit coloring period exogenous ABA treatment accelerated...