【摘要】 反季节龙眼在果实发育过程中落果现象非常严重。前期的研究表明，果实中碳水化合物水平的下降与果实脱落密切相关。为了进一步了解不同发育时期果实的碳水化合物代谢变化与脱落差异的关系，以反季节储良龙眼为试材，果穗从树上剪下后迅速插入清水中并去除叶片诱发果实脱落，通过测定胁迫处理下3个发育时期果实落果率、呼吸耗氧量、果柄分离力变化，检测不同光强对3个时期果实呼吸的影响，发现不同发育时期龙眼果实对脱落的敏感性不同。饥饿胁迫迅速启动了各发育时期果实的脱落响应，但3个时期果实脱落响应差异较大，幼果期果实对饥饿胁迫的响应较中期和后期延后2 d，果实发育中期和后期脱落响应更剧烈；幼果期果实呼吸耗氧量较低，而果实发育中期和后期呼吸耗氧量较高；随着光强的增加，仅幼果期果实呼吸作用未造成氧气的下降，还出现了氧气的释放。幼果期果柄分离力下降也较果实发育中期和后期缓慢。因此，本研究结果表明，在胁迫条件下果实呼吸作用与果实脱落密切相关，果实呼吸强度越强；在饥饿胁迫条件下果柄分离力下降越快，果实脱落越快。龙眼幼果期可通过果皮进行光合作用部分代偿呼吸对碳水化合物的消耗。幼果期饥饿胁迫下落果慢的主要原因是低的呼吸消耗和具有一定的光合能力，因此，龙眼幼果是一个部分自养的器官。更多还原

【Abstract】 Fruit abscission in off-season longan is very serious during fruit development in Hainan, China, and severely affectse the formation of production. However, the research on the regulation of longan fruit abscission mainly is focused on fruit thinning, and there are very few studies on fruit preservation. The mechanism of abscission is mainly focused on hydrolase genes and reactive oxygen species, there is no report of fruit respiration on carbohydrate metabolism affecting fruit abscission. Previous studies showed that the decrease in carbohydrate level in fruit was closely related to fruit abscission. In order to further understand the relationship of carbohydrate metabolism and abscission, fruit clusters of off-season Chuliang longan were detached from tree body, the peduncles were immediately inserted into pure water and defoliation treatmented after detachment, which caused starvation stress and induced fruit abscission. Therefore, detachment of the fruit clusters from the tree served as starvation stress treatment. Change in the fruit abscission rate in the starvation stressed fruit clusters, respiratory oxygen consumption rate and fruit removal force in the three developmental stages under detachment were examined, and the effects of different light intensity on fruit respiration in the three stages were analyzed. It was found that longan fruit at different developmental stages differed in sensitivity to starvation stress, which rapidly initiated the fruit abscission response in all the three stages, but there were large differences in speed of fruit shedding. Young fruits responded to starvation stress for two days later than those in the middle and the late fruit development stage would lead to more intense fruit abscission response in the middle and the late stages. Respiratory oxygen consumption rate was the lowest in the young fruit stage. With the increase of light intensity,the respiration of young fruits did not cause a decrease in oxygen, but rather a release of oxygen. The decrease in the fruit removal force was also slower than that in the middle and late stages of fruit development. Therefore, it is concluded that fruit respiration was closely related to fruit abscission under starvation stress. Stronger fruit respiration intensity would result in faster fruit abscission under starvation stress and faster fruit removal force decreases. Young green fruits may carry out photosynthesis, which partially compensates for the respiratory consumption of carbohydrates in fruit, resulting in slower fruit abscission under starvation treatment. In the longan young fruit stage, the main reasons of slow fruit abscission under starvation stress are low respiratory oxygen consumption rate and certain photosynthetic capacity. Therefore, it is conclude that the young longan fruit is a partially autotrophic organ.更多还原