中文摘要：

培育抗倒能力强的超高产品种是水稻高产、优质、安全生产的重要课题。本研究旨在探讨超级稻连粳7号的抗倒生理特性,为超高产育种提供理论依据。以抗倒伏超级稻连粳7号为试验材料,不抗倒品种中粳12-9为对照,设置不同氮素水平,以倒伏指数作为衡量植株抗倒伏能力的指标。在齐穗后25 d,研究水稻基部第1节间（I1）、第2节间（I2）、第3节间（I3）、第4节间（I4）抗倒伏能力和主要物理性状的差异,并对倒伏指数、抗折力与茎秆主要物理性状进行相关分析,结果表明超级稻连粳7号倒伏指数低、抗倒伏能力强的主要原因是：（1）I1和I2短,在试验范围内株高增高幅度小;（2）叶鞘干质量大,单位节间干质量大,茎秆的充实度好;（3）基部节间抗折力与茎壁厚、茎秆干质量、叶鞘干质量、单位节间干质量、节间至顶鲜质量呈显著或极显著正相关,与株高、重心高度、相对重心高度、茎秆粗、节间基部至顶长无显著相关关系。超级稻连粳7号基部节间短,茎秆充实程度好是抗折力大、倒伏指数小、抗倒伏能力强的直接原因。

英文摘要：

It is an important subject to develop lodging-resistant varieties for the high-yielding, high-quality and safe production of rice. The lodging-resistant mechanism of rice Lianjing 7 was studied using lodging index as a measuring stand-ard of lodging resistance. None-lodging-resistant medium Japonica rice Zhongjing 12-9 was set as control. Lianjing 7 showed short basal internode 1（I1） and internode 2（I2）,small increase of plant height,heavy dry matter of internode per unit and leaf sheath,and good stem plumpness. The basal internode breaking-resistance exhibited positive correlations with stem wall thickness,stem dry matter,leaf sheath dry matter,dry matter of internode per unit,and fresh weight from inter-node to plant top, and no correlations with plant height, gravity center height, stem diameter, and the length from basal internode to top. The short basal internode and good stem plumpness might have contributed to the strong breaking-resi- sance,small lodging index and strong lodging resistance of Lian- jing 7.