罗汉果无籽果实变小的原因分析

Reasons that Seedless Fruits of Siraitia grosvenorii Become Small

目的:探讨罗汉果无籽果实变小的原因。方法:以三倍体F050和二倍体F049雌性株系为试验材料,进行三倍体与二倍体果实膨大动态、基因表达和细胞发育差异比较研究。结果:授粉后20 d左右,三倍体果实停止膨大,比二倍体果实提早约10 d;授粉后20 d,三倍体果实aux基因表达水平显著高于二倍体果实,ipt、cyt-p450、spds和cycB、cycD1、cycD3、cdkA、cdkB、exp、xth基因表达水平则显著低于二倍体果实;三倍体果实多数果肉细胞发育停滞在小型细胞阶段。结论:三倍体无籽果实变小,是其受精不良而胚败育,内源IAA和CTK、GA、SPDS合成严重缺乏,造成调控细胞分裂与膨大蛋白基因的表达受抑制,从而果肉细胞不能正常分裂与膨大所致。

Objective：To study the reasons that the seedless fruits of Siraitia grosvenorii developed to smaller ones. Methods：The difterences of fruit expanding, gene expressing and cell development were investigated between the triploid and diploid fruits fi＇om two strains F050 and F049. Results ： The results showed the expanding of triploid fruits was stopped about 20 days after artificial pollination, 10 days earlier than the diploid fruits. Meanwhile,it was also investigated that aux expressing level in the triploid fruits was greatly high- er than that in diploid fruits, while its ipt, cyt-p450, spds, cycB, cycD 1, cycD3, cdkA, cdkB, exp and xth expressing level were greatly lower than that in diploid fruits. The majority of sarcocarp cells of the triploid fruits kept in the stage of small ones comparing with the diploid fruits. Conclusion：The expression of the genes of the proteins involving cell division and expansion was inhibited as the significant re- duction of endogenous 1AA, CTK, GA and SPDS after bad fertilization and the embryo abortion,which resulted in the end of division and extension of sarcocarp cells. Above reasons induce small fruits of triploid seedless Siraitia grosvenorii.