Abstract: long grain rice variety(Minghui 63) and a short grain rice variety(Chuan 7) were used to observe hull growth and cytological characteristics. The results showed that the internal parenchyma cells carry out symmetrical division in palea at the flower primordium stage. The palea cells continue dividing until the stage of pollen mother cell, ceasing sequentially from the apical to the basal parenchyma cells. Ouring pollen mother cell meiosis, palea cells start rapid elongation and reach the maximum length at the late microspore stage. The middle and basal internal parenchyma cells provide larger contribution to the total length than the apical cells. There was significant difference in total cell number between the two varieties throughout the growth stage, whereas no significant difference in cell length at the late microspore stage. The number of internal parenchyma cells of Minghui 63 was 60.98% more than that of Chuan 7, whereas the middle and basal cell lengths were only 1.81% and 805% longer, respectively. Thus, it is concluded the cell number is the main factor affecting the final palea length.

Key words: hull, palea, rice, grain shape, cytology

摘要： 以籼稻长粒品种明恢63和短粒品种川7为材料，利用石蜡制片技术研究了水稻稃片发育过程，并比较长粒和短粒品种稃片发育的细胞学差异。结果表明，小花原基时，稃片纵向各区段均匀分裂，随着发育的进行，稃片上部细胞最早停止分裂，基部细胞分裂结束最晚。至花粉母细胞末期，稃片细胞结束分裂。花粉母细胞减数分裂期，稃片细胞开始进入快速伸长生长阶段，至小孢子晚期稃片长度达到最大值，而且稃片的中、基部细胞对其长度的贡献大于上部细胞。长粒和短粒水稻稃片发育过程基本一致，但长粒和短粒水稻内稃薄壁细胞数目在稃片发育过程中，始终存在极显著差异，细胞长度在稃片长度定形时并没有明显区别。稃片达终长度时，长粒品种内稃薄壁细胞数目比短粒品种多60.98％，而中、基部细胞长度仅增加1.81％和8.05％。因此，细胞数目是导致水稻长粒和短粒品种稃片长度差异的主要因素。

关键词: 稃片, 内稃, 水稻, 粒型, 细胞学