中文摘要：

【目的】培育抗倒能力强的水稻品种是实现水稻高产优质所面对的重要课题。本研究旨在探讨北方直立穗型粳稻抗倒性，为提高北方粳稻抗倒性，实现水稻高产优质提供一定的理论依据。【方法】以12个不同穗颈弯曲度的北方粳稻品种为试材，于齐穗后30d，研究了直立穗型与弯曲穗型粳稻地上部分各节间抗倒伏能力的差异，并通过对茎秆抗折力与茎秆形态性状、茎秆解剖结构和茎秆化学成分进行相关分析，研究了直立穗型粳稻抗倒的茎秆形态特点与生理基础。【结果】直立穗型粳稻穗下第1节间（N1）、第2节间（N2）、第3节间（N3）和第4节间（N4）的弯曲力矩与弯曲穗型品种差异不显著，但N1、N2、N3的抗折力却显著提高，从而使N1、N2、N3的倒伏指数显著或极显著低于弯曲穗型粳稻，说明中上部节间抗倒能力明显增强。进一步分析直立穗型与弯曲穗型粳稻茎秆解剖结构、化学成分以及它们与茎秆抗折力的相关性后发现，直立穗型粳稻N1、N2、N3抗折力强的主要原因是：（1）茎壁厚度和茎壁面积增大，节间抗折的物理性状明显提高；（2）大小维管束数目多，大小维管束、韧皮部、木质部面积增大，节间内部组织的结构明显改善；（3）纤维素含量高，支持细胞壁结构的物质含量多。【结论】茎壁厚度、茎壁面积、维管束性状及纤维素含量可以作为选育抗倒伏品种的主要参考指标。就北方粳稻而言，培育直立穗型品种，更容易获得抗倒性强的品种。

英文摘要：

[Objective] In rice breeding, improvement of lodging resistance has been a main aspect for high-yield and excellent-qualities. This study investigated the lodging resistance of erect panicle Japonica rice in northern China. It would be beneficial to improve ment of lodging resistance of Northern japonica rice and realization of high-yield and excellent-quality in rice. [Method] Thirty days after heading, the lodging resistance of every elongating internodes of erect panicle type rice （EPT） and curved panicle type rice （CPT） were studied by using 12 japonica rice cultivars as materials and T-test as statistical analysis method. Furthermore, to demonstrate the reason why erect panicle type japonica rice has better lodging resistance than curved panicle type japonica rice, the correlations between the breaking resistance of the culm and its characteristics of physics and mechanics were studied. [Result] The results revealed that there was no significant difference in bending momen.t of the 1st, 2nd, 3rd and 4th internodes between erect panicle type rice and curved panicle type rice （CPT）. But EPT had greater breaking resistance of the 1st, 2nd and 3rd internode than CPT. So that the lodging index of the 1st, 2nd and 3rd internodes of EPT was lower than that of CPT. The correlations between the breaking resistance of culm and its morphological traits, anatomical features, chemical components were further studied. There were many reasons for the breaking resistance of 1 st, 2nd and 3rd internodes of EPT increased. Firstly, EPT had thicker culm wall and larger culm wall area than EPT. Secondly, the mumber of vascular bundles, the area of vascular bundles, the area of phloem and the area of xylem of EPT were lager than those of CPT. Thirdly, EPT had higher cellulose content in comparison with CPT. [.Conclusion] In selection of lodging resistant cultivars, one should consider those characterized with thicker culm wall, larger culm wall area, better vascular bundle characters with high cellulose content in th