人工疏果对龙眼果实大小、内源激素和细胞壁成分的影响

在花后1个月内分2次对储良龙眼(Dimocarpus Longan Lour.cv.Chuliang）进行人工疏果处理（总疏果幅度50%左右）。结果表明，人工疏果可以促进果实的生长（与对照相比，横径和果实重量至采收分别增加了7.1%和22.5%）。果实中GA4 7和ZRs含量均表现为疏果处理大于对照，其差异在出现含量高峰时增大，而IAA含量也是疏果处理大于对照，但其差异主要出现在花后45d和花后100d。在整个果实发育期间，疏果处理与对照果皮中细胞壁成分变化的趋势基本相似，处理只是在后期才增加了果皮细胞壁中果胶，半纤维素和纤维素的含量，分别出现在花后90d后、60d和75d后，疏果处理对可溶性糖的含量无影响。根据试验结果推测：在果实发育前期，疏果处理显增加的内源细胞分裂素类水平，可能有利于促进细胞分裂和细胞数量；而在果实发育后期，增加的果皮细胞壁成分则为人工疏果促进果实生长（主要表现为细胞的膨大）提供了物质基础。

Effects of Hand-thinning on the Longan Fruit Size, Endogenous Hormones Level and Pericarp Cell Wall Components

The effects of hand-thinning on the longan fruit growth and its endogenous hormones (GA4 7, ZRs, IAA) levels and pericarp cell wall components were studied. The' results showed that fruit hand-thinning promoted the growth of individual fruit diameter and flesh weight by 7.1 % and 22.5 % respectively as compared with the control. The contents of GA4 7 and ZRs in treated fruits were higher than that of the control throughout fruit development, and their differences were highly significant when the peaks of their contents occurred. Significant difference in IAA level between the treated fruits and control took place in 45 and 100 days after anthesis. The change trend of pericarp cell wall components between hand-thinning and control was basically the same during the whole fruit development. However, fruit thinning treatment increased the contents of pectin, hemicellulose and cellulose in pericarp cell walls only at the later stage of fruit development (after 90, 60 and 7.5 days after anthesis respectively), but produced no effect on soluble sugar content. It was suggested that the remarkable increase in cytokinin level at the early stage by fruit hand-thinning might have promoted cell division in periarp and thus increase cell number, and that the increased cell wall components at the late stage by hand-thinning might have provided material source for the promoted growth of treated fruits.