增加种植密度是近年来我国乃至世界玉米大面积高产的最有效途径，而玉米密植后倒伏问题严重制约了单产的突破，增强茎秆抗倒伏强度是解决玉米密植高产的关键。本项目选用不同耐密性品种及其亲本自交系为材料，采用不同种植密度和人工遮光相结合的试验方法，从遗传背景差异、种植密度差异、受光环境差异等角度，研究玉米茎秆结构性物质纤维素和木质素的变化规律，探讨玉米茎秆基部节间纤维素、木质素合成代谢与茎秆强度形成的相互关系，明确不同抗倒伏能力的品种及亲本茎秆纤维素、木质素合成过程中关键酶活性及激素含量的差异；揭示种植密度、遮荫处理对茎秆纤维素、木质素代谢关键酶活性和激素含量的影响机理；阐明茎秆强度形成的内在（遗传）和外在（环境和措施）影响因素和调控途径。研究结果将为玉米耐密坚秆品种选育提供理论依据，并为新疆玉米进一步挖掘密植增产潜力提供技术支撑。

Increasing plant density is one of the most effective means to improve maize yield in China and the world in recent years. However, stalk lodging limits yield seriously under close planting. Enhancement of biomechanical stalk strength is a key method to decrease lodging for close planting high-yield in maize production. This project focuses on the study of the changes in cellulose and lignin content of maize stalk, by using various density-tolerant maize cultivars and their parental inbred lines. The relationship between cellulose and lignin accumulation with mechanical strength of the basal internodes will be study under the different planting density and shading treatments with various maize hybrid combinations. The difference of the key enzymes activities and the amounts of hormones during the cellulose and lignin synthesis will be determined, and then to reveal the influencing mechanisms of plant density and shading on activities of key enzymes and the amounts of hormones during cellulose and lignin synthesis. We will clarify the outside (environment and cultivation practices) and inside (genetic) factors of the determining mechanisms and the regulation pathway of the stalk lodging resistant strength. This study will provide theoretical bases for breeding stiff stalk lodging resistance maize cultivars, and help for improving maize yield under high planting density in Xinjiang.