以不耐荫品种豫玉22（YY22）和较耐荫品种郑单958（ZD958）为材料，采取盆栽方式，研究苗期3片展开叶至6片展开叶期间，中度遮荫（42%透光率）和重度遮荫（27%透光率）对玉米根系活力及抗氧化生理指标的影响。结果表明，根系伤流量随着弱光胁迫程度的增加而减少。根系活力则表现为先增后降，在重度遮荫时，ZD958根系活力未显著变化，YY22则低于对照。随着弱光胁迫程度的增加，ZD958和YY22根细胞内活性氧积累，质膜透性增大，丙二醛（MDA）、脯氨酸、可溶性蛋白质和可溶性总糖含量显著增加，抗氧化防护酶（SOD、POD、CAT、APX、GR）活性升高，抗氧化剂（GSH和ASA）含量增加，AsA/DHA和GSH/GSSG值降低。总体上，YY22根尖的渗透调节物质及质膜透性变化幅度较大，ZD958根尖的抗氧化防护酶活性及抗氧化剂含量的变化幅度较大。

The effect of low light stress on root growth of two maize(Zea mays L.) cultivars, Zhengdan958 (ZD958, shade-tolerance) and Yuyu 22(YY22, shade-sensitive), were investigated under 42% photon flux density (PFD) and 27% PFD at seeding stage. The result showed that, with low light stress increased, the root bleeding inten-sities of two maize cultivars both decreased, while the root activity first increased and then decreased. There is a phe-nomenon that when heavily shaded, the root activity of ZD958 was not significantly changed, but that of YY22 was lower than its control. The increasing of low light stress induced the accumulation of reactive oxygen, subsequently resulted in the increase of MDA and permeability of cell membrane, as well as the increase of osmoticum due to the increased contents of proline, soluble protein and soluble carbohydrate. The antioxidative enzymes(SOD、POD、CAT、APX and GR) activities and antioxidants(AsA and GSH) contents increased gradually with the aggravation of low light stress. But AsA/DHA ratio and GSH/GSSG ratio was gradually decreased. Under low light stress, the change of osmotic adjustment and plasma membrane permeability of the root tip of YY22 was larger than those of ZD958, while the change of antioxidant protective enzyme activity and antioxidant content in the root tip of ZD958 were larger than those of YY22.

国家重点研发计划项目（2017YFD0301101）、NSFC-河南人才培养联合基金项目（U1304405）