作为C4植物，玉米是一种喜光作物，光照不足将严重影响其产量。近年来，黄淮海夏玉米生长期内连续阴雨、光照不足的天气时常发生，严重影响其生长发育和产量形成。本研究在大田条件下设置不同遮阴和增光处理，旨在实现弱光和增光正反两个效应，通过显微结构观察明确弱光对夏玉米穗分化和发育特性的影响；在此基础上，利用13C和15N同位素标记技术，探讨弱光条件下夏玉米碳素和氮素的同化、运转与分配特性；研究弱光对夏玉米内源激素含量与平衡和籽粒胚乳细胞增值特性的影响；探讨外源物质对弱光条件下夏玉米穗分化的调控及其生理机制；明确弱光影响夏玉米穗分化的生理机制。以期为高产高效夏玉米生产的育种和栽培提供科学依据。

As C4 plant summer maize is a strictly light adapted species, grain yield of maize is significantly decreased in low light conditions. Continuous rain occurrs frequently during the maize-growing season, resulting in insufficient solar radiation and yield reduction of summer maize in Huanghuaihai region, the growth and yield of summer maize have been affected seriously. In this study, shading and increasing light treatments are to be designed in the field. The objectives of this study are to elucidate the physiological mechanism of spike differentiation of summer maize in low light, to study the uptake and distribution characteristics of nitrogen and carbon in summer maize plants by the isotope tracers of both 15N and 13C, and to explore the effects of shading on endogenous hormones content of summer maize, and to study the regulation of different exogenous hormones on the spike differentiation of summer maize. The expected results will be helpful for the breeding and agronomic management practices improvement of summer maize with high yield and high efficiency.