弱光胁迫对不同基因型玉米籽粒发育和碳氮代谢的影响

以不耐阴型玉米豫玉22和耐阴型玉米郑单958为试验材料，设置自然光照和弱光胁迫2个处理，研究弱光胁迫对不同基因型玉米籽粒建成和碳氮代谢的影响，探求弱光胁迫下碳氮代谢与籽粒建成的关系。结果表明，弱光胁迫下，玉米籽粒生长发育减缓，败育数增加，体积和干重降低；果穗顶部籽粒可溶性糖、蔗糖含量和全氮含量升高, 淀粉含量和碳氮比降低；豫玉22胚乳细胞中淀粉粒密度降低，郑单958与对照相近。弱光胁迫下，不耐阴型玉米豫玉22果穗籽粒的生长发育减缓程度大于耐阴型玉米郑单958，同一基因型果穗顶部籽粒生长发育减缓程度大于中部籽粒，耐阴型玉米郑单958在恢复自然光照后籽粒体积、干重、籽粒碳氮含量和碳氮比与对照之间的差异均小于豫玉22，表现出更强的补偿效应。淀粉合成能力和碳氮比的下降可能是弱光胁迫条件下籽粒发育不良以致最终造成败育的主要原因。

Effects of Low-light Stress on Kernel Setting,and Carbon and Nitrogen Metabolism of Different Maize (Zea mays L.) Genotypes

Light is one of the important factors influencing kernel growth and development of maize (Zea mays L.). A split plot experiment was conducted under field conditions to study the effects of low-light stress and light recovery on kernel setting, and carbon and nitrogen metabolism of different maize genotypes in 2011 and 2012. Light treatments (natural light and 50% shading from three days before tasselling to ten days after silking) were the main plots and cultivars low light sensitive hybrid (Yuyu 22) and low light tolerance hybrid (Zhengdan 958)] were sub-plots. The results showed that low-light stress delayed the growth and development of kernels, raised the number of abortive kernel, reduced kernel volume and dry weight. Contents of soluble sugar, sucrose and starch of apical kernel were increased while the content of nitrogen and C/N ratio decreased. Starch grain density in kernel endosperm cells of YY22 reduced while that of ZD958 almost remained the same. Differences between treatments of YY22 were greater than those of ZD958, the reduction of kernel growth and development was greater in the apical than in the middle of ear. ZD958 showed stronger compensatory effect after light recovery, differences between light treatments and the control in kernel volume, dry weight, kernel carbon and nitrogen contents and C/N ratio of ZD958 were lower than that of YY22. The declines of the starch synthesis and C/N ratio are the primary causes leading to kernel abortion.