主枝环剥对澳洲坚果幼果碳水化合物与内源激素水平的影响

【作者】 杨为海； 向沛锦； 曾辉； 林文秋； 邹明宏； 万继锋； 张汉周； 陆超忠；

【机构】 中国热带农业科学院南亚热带作物研究所； 华中农业大学园艺林学学院；

【摘要】 Macadamia flowers profusely but sheds more than 98% of flowers and fruitlets within 8 weeks after anthesis. There is good evidence for macadamia that girdling fails to ramp up yield despite increasing the early fruit set, but the effect on its physiological mechanism is not well defined. In this study, we applied a 6 mm girdle to the main branches of 6-8 cm diameter at early fruit development, to investigate the effect of main-branch-girdling（MBG） treatment on fruit set and the levels of carbohydrates and endogenous hormones in leaves, bearing shoots and fruit. Results showed that MBG significantly reduced young fruit drop but unchanged the abscission process. Meanwhile, the treatment significantly increased the contents of total soluble sugars and starch in the leaves and bearing shoots, and also enhanced the levels of total soluble sugars included glucose, fructose and sucrose in the husk and seed. These findings suggested that the availability of carbohydrates for fruit retention was improved by MBG. Additionally, MBG increased the indole-3-acetic acid（IAA）, gibberellin（GA₃） and zeatin-riboside（ZR） levels but decreased the abscisic acid（ABA） level in the husk and seed, indicating that MBG reduced the early fruit drop by modifying the balance of endogenous hormones. Therefore, a positive interplay between carbohydrates and endogenous hormones was involved in the reduction of early fruit abscission induced by MBG in macadamia.更多还原

【Abstract】 Macadamia flowers profusely but sheds more than 98% of flowers and fruitlets within 8 weeks after anthesis. There is good evidence for macadamia that girdling fails to ramp up yield despite increasing the early fruit set, but the effect on its physiological mechanism is not well defined. In this study, we applied a 6 mm girdle to the main branches of 6-8 cm diameter at early fruit development, to investigate the effect of main-branch-girdling（MBG） treatment on fruit set and the levels of carbohydrates and endogenous hormones in leaves, bearing shoots and fruit. Results showed that MBG significantly reduced young fruit drop but unchanged the abscission process. Meanwhile, the treatment significantly increased the contents of total soluble sugars and starch in the leaves and bearing shoots, and also enhanced the levels of total soluble sugars included glucose, fructose and sucrose in the husk and seed. These findings suggested that the availability of carbohydrates for fruit retention was improved by MBG. Additionally, MBG increased the indole-3-acetic acid（IAA）, gibberellin（GA₃） and zeatin-riboside（ZR） levels but decreased the abscisic acid（ABA） level in the husk and seed, indicating that MBG reduced the early fruit drop by modifying the balance of endogenous hormones. Therefore, a positive interplay between carbohydrates and endogenous hormones was involved in the reduction of early fruit abscission induced by MBG in macadamia.更多还原