玉米茎秆细胞壁和组织构建对抗压强度的影响

Effects of Stalk Cell Wall and Tissue on the Compressive Strength of Maize

耐密抗倒伏玉米品种是玉米育种的重要方向,探究影响玉米茎秆抗压强度的机制是培育玉米新品种的重要途径。本实验采用组织化学、显微观察的方法研究了10个玉米品种茎秆的形态结构、解剖特征和细胞壁的化学组成,并分析了这些变量之间的相关性,结果表明:茎的皮层/半径、厚壁组织比例、机械组织比例和纤维素含量、木质素含量与抗压强度呈极显著正相关关系;薄壁组织比例、茎长/茎粗、维管束个数与抗压强度呈极显著负相关关系。利用共线性诊断和逐步线性回归分析发现,影响茎秆抗压强度的主要因素为皮层/半径、机械组织比例、维管束个数、纤维素含量和木质素含量。利用通径分析进一步定量研究了这5个变量与抗压强度之间的直接作用和间接作用,明确了决定玉米茎秆抗压强度的主要因素为纤维素含量、木质素含量和单位面积维管束个数。本实验还建立了玉米茎微观结构与细胞壁化学构成的数学模型,为进一步揭示玉米茎微观力学形成机理提供了思路,进而为耐密抗倒伏玉米育种提供了研究方向。

Density-tolerant and lodging-resistant maize varieties are crucial directions for maize breeding in agricultural science. Recent breakthroughs in research on the mechanism that influences the lodge resistance of maize have become an additional approach to breed new varieties of maize. Histochemical techniques and micro-examination methods were used to study the morphological structure of the stalks, anatomical characteristics and chemical compositions of the cell walls of ten maize varieties,and the correlations between these variables were analyzed. The results suggested a significant positive correlation between the cortex / radius,thick-wall tissue proportion,mechanical tissue proportion,content of cellulose,content of lignin and lodge resistance strength,and an significant negative correlation between thin-wall tissue proportion,stem height / stem diameter,number of vascular bundles and lodge resistance strength. Based on co-linearity diagnosis and stepwise linear regression, we concluded that the main factors influencing lodge resistance strength included cortex / radius,mechanical tissue proportion,number of vascular bundles,and contents of cellulose and lignin. Moreover,through quantitative study of the direct and indirect effects between the fivevariables and anti-compression strength,we concluded that the main factors determining straw compressive strength included cellulose, content of lignin and number of vascular bundles per unit area. In addition,a biological mechanics model between the microstructure of maize stalks and the chemical composition of the cell walls was established,which will provide insight into the formation mechanism of the corn stem. Furthermore,this study provides a new direction for the breeding of density-tolerant and lodging-resistant maize varieties.