Abstract: The relationship between rice stem and lodging resistance was studied by topdressing different N and K fertilizer in different periods for Indica hybrid rice Liangyou 6326. The results showed that the smallest lodging index was fertilizered in top 5th leaves, the biggest one was fertilizered in flag leaves in N fertilizer trials; The smallest lodging index was fertilizered in top 2nd leaves, the biggest one was fertilizered in top 3rd leaves in K fertilizer trials. The significance of robust degrees of basal internodes to lodging resistance is as follows: 2nd basal internodes > 1st basal internodes > 3rd basd internodes. The lodging index of stem is effected by follow factors: basal internodes dry weight > basal internodes length > basal internodes wall thickness > basal internodes inner diameter.

Key words:  Indica hybrid rice, leaf periods, fertilizer, lodging resistance

摘要： 以籼型杂交稻两优6326为材料，通过不同时期追施不同剂量的N肥与K肥，研究了不同时期追肥对水稻抗倒性的影响，及水稻茎秆的生长发育与植株抗倒性的关系。结果表明，N肥试验中，倒伏指数最小的是倒5叶期施肥，最大的为倒1叶期施肥；K肥试验中，倒伏指数最小的是倒2叶期施肥，最大的为倒3叶期施肥。基部节间的健壮程度与水稻的抗倒伏关系为：基部第二节间＞基部第一节间＞基部第三节间；对茎秆倒伏指数的影响大小为：基部节间干质量＞基部节间长度＞基部节间壁厚＞基部节间内径，而节间外径大小与植株抗倒关系不密切。

关键词: 杂交籼稻, 肥料, 抗倒性, 叶龄期