Abstract: The germination of rice pollen grain in vitro and the growth of pollen tube in pistil were observed with a microscope.The stigma was removed at different time after pollination to investigate seed setting rate of floret.Results showed that rice pollen grain germinated 2 min after pollination and pollen tube would penetrate stigma into style in 5-10 min,30 min later the end of pollen tube reached the bottom of ovary,then some pollen tubes arrived at the embryo sac 40 min after pollination and meanwhile a small amount of callose formed in the pollen tubes,50 min later a great deal of callose was found,and the pollen grain began to shrink.The growing speed of pollen tube in rice stigma,style and ovary was 1500,5000,5400 μm/h,respectively.The seed setting rate was quite low when the stigma was removed at 10-15 min after pollination,and then it increased gradually from 20 min to 50 min,finally it was over 60% at 50 min after pollination and tended to be stable.

Key words: rice, pollen germination, growth of pollen tube, seed setting rate, microscopic observation

摘要： 用显微镜观察水稻花粉粒的萌发、花粉管在雌蕊中的生长以及授粉后不同时间剪除柱头处理对颖花结实率的影响。 水稻花粉粒在授粉2 min后开始萌发；5～10 min后花粉管穿过柱头进入花柱生长；约经30 min花粉管顶端到达子房基部；40 min时有些花粉管顶端可接近胚囊，此时花粉管内胼胝质形成，但数量较少；50 min后花粉管内胼胝质塞大量形成，花粉粒萎缩干瘪。水稻花粉管在柱头、花柱和子房中的生长速率分别为1500、5000、5400 μm/h。水稻授粉后10～15 min剪除柱头的处理只有极少量颖花结实，授粉后20～50 min剪除柱头处理的颖花结实率随处理时间推迟而升高，授粉后50 min剪除柱头处理的结实率达60％以上，接近正常。

关键词: 水稻, 花粉萌发, 花粉管生长, 结实率, 显微观察