结实期弱光胁迫对甜玉米籽粒灌浆和叶片衰老的影响

为探索甜玉米生长发育对花后弱光的响应,以京科甜183和京科甜533为材料,结实期(人工授粉至鲜食期)利用遮阳网进行50%遮光处理,研究结实期弱光胁迫对甜玉米籽粒灌浆和叶片衰老的影响。结果表明,春播和夏播处理下,弱光胁迫均使甜玉米穗粒数减少,鲜籽粒重降低,进而导致产量损失;随灌浆进程推进,鲜籽粒体积、鲜重、干重和叶片丙二醛(MDA)含量逐渐升高,籽粒含水率、叶片可溶性蛋白含量和SPAD值逐渐下降。结实期弱光胁迫显著降低鲜籽粒体积、鲜重和干重,花后27 d时籽粒含水率较低,叶片可溶性蛋白质含量和SPAD值降低,MDA含量增加,过氧化氢酶、超氧化物歧化酶和过氧化物酶活性提高。总体上,弱光胁迫能加快甜玉米叶片衰老,进而限制籽粒灌浆,导致籽粒重量下降。本研究结果为甜玉米结实期叶片衰老和籽粒灌浆在低光照条件下的调控提供了理论参考。

Effects of Weak-light Stress After Pollination on Grain Filling and Leaf Senescence in Sweet Maize

In order to explore the response of sweet maize growth to low sunlight condition after pollination,the effects of weak-light stress (50％ light deprivation by shading net from pollination to fresh stage) on the grain filling and leaf senescence of sweet maize were studied using Jingketian183 and Jingketian533 as materials.The results indicated that shading reduced the grain number and fresh grain weight,which resulted in the loss of fresh grain yield loss under both spring and summer sowing conditions.With the grain development,the fresh grain volume and weight,dry grain weight,and leaf malondialdehyde (MDA) content increased,grain moisture content,leaf soluble protein content and SPAD value decreased gradually.Under weak-light stress conditions the grain weight (dry and fresh) and volume decreased significantly,and the grain moisture content at 27d after pollination was lower.In addition,soluble protein content and SPAD reduced,while MDA content was increased,and the activity of catalase,superoxide dismutase and peroxidase were enhanced significantly.Generally,shading accelerated senscence of the leaf and restricted grain filling of sweet maize,result in the decline of grain weight.The results afford a theoretical reference for regulating the grain filling and leaf senescence of sweet maize under low sunlight conditions after pollination.