小麦茎秆弯曲特性与密度间的关系

目的]研究小麦茎秆弯曲特性与密度间的关系。方法]取郑麦9023和豫麦25茎杆基部第2节间，去掉叶鞘，做弯曲试验以及密度测定试验。利用微机控制非金属材料万能试验机，采用三点弯曲法对去鞘茎秆做弯曲试验。加载前，用游标卡尺测定茎秆外径及节间长度。采用非接触式光学应变引申仪测定变形量，加载速率为10mm／min。当茎秆发生明显的曲折时，停止加载。根据荷载挠度曲线，计算弯曲强度值、弹性模量值、抗弯刚度值。密度测定试验：用电子天平测定茎秆第2节问的重量，根据茎秆的外径、壁厚以及节间长，计算其体积，重量／体积即为密度值。结果]在小麦灌浆期，茎秆基部弹性模量、惯性矩、抗弯刚度及密度在品种间存在显著差异（P〈0．05），弯曲强度及含水率在品种间无显著差异（P〉0．05）；且其基部第2节间的弹性模量、弯曲强度、抗弯刚度与密度呈正相关关系，与含水率呈负相关关系。茎秆密度值越大、含水率越低，抗弯刚度值、弯曲强度值越大，茎秆越不易倒伏。结论]该研究结果为小麦的高产栽培、抗倒伏研究提供了参考依据。

Relationship between Bending Property and Density of Wheat Stem

Objective] The aim is to research the relationship between bending property and density of wheat stem. Method ] The bending properties such as elastic modulus, bending strength, flexural rigidity, moment of inertia, density and water content of the second base internodes of Zhengmai 9023 and Yumai 25 were determined. Result] The results show that during filling stage, there are significant differences in the elastic modulus, moment of inertia, flexural rigidity and density among wheat varieties, while there are no significant differences in the bending strength and water content among wheat varieties. The moment of inertia, flexural strength and flexural rigidity have positive relationship to density but negative relationship to water content. Conclusion] The study results provide some references for the research on high yield cultivation and lodging resistance of wheat.