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

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 five variables 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.