Germination of Pollen and Growth Dynamic of Pollen Tube in Rice

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.