['To study the reasons that the seedless fruits of Siraitia grosvenorii developed to smaller ones.', 'The differences of fruit expanding, gene expressing and cell development were investigated between the triploid and diploid fruits from two strains F050 and F049.', '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 higher than that in diploid fruits, while its ipt, cyt-p450, spds, cycB, cycD1, 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.'] Do [ Reasons that seedless fruits of Siraitia grosvenorii become small ]?