玉米幼苗响应低铁胁迫的根系形态与干物质积累特征

揭示不同品种玉米幼苗根系形态与物质积累对低铁（Fe）胁迫的响应,为玉米Fe营养研究提供理论依据。采用营养液培养的方法,研究32个玉米品种在正常Fe（100μmol/L）和低Fe（10μmol/L）条件下根系形态、物质积累特性和Fe吸收的变化。结果表明,低Fe胁迫下,32个玉米品种的幼苗根系干重、地上部干重、单株干重、总根长、叶绿素含量、叶面积、根表面积、根体积、根长、株高、根尖数、可见叶、展叶、茎粗、单株Fe积累量、Fe吸收效率和叶片活性Fe含量均显著降低,根平均直径、根冠比和Fe生理效率显著增加,但品种间存在差异。通过低Fe效应值及2个Fe水平的聚类分析发现,同一Fe水平下,玉米幼苗各性状的综合表现存在品种差异,根据2个Fe水平综合表现筛选得到3个Fe高效品种正红2号、汉单999与荃玉9号和3个Fe低效品种川单455、川单189与成单30。低Fe胁迫下,Fe高效品种单株干物重、单株Fe积累量和Fe吸收效率的降幅与根冠比的增幅均低于Fe低效品种,而Fe生理效率的增幅高于Fe低效品种。综合分析表明,Fe高效品种对低Fe胁迫具有更强的适应性,且提高Fe生理效率是玉米幼苗适应低Fe胁迫的重要生理机制。

Root Morphology and Dry Matter Accumulation of Maize Seedlings in Response to Low Iron Stress

In the present study, the response of root morphology and material accumulation of different maize varieties to low iron stress was revealed, which provided theoretical basis for the study of iron nutrition in maize. The nutrient culture method was used to study the changes of root morphology, dry matter accumulation and iron absorption of 32 maize varieties under normal iron (100μmol/L) and low iron (10μmol/L) conditions. The results showed that the root dry weight, shoot dry weight, dry weight per plant, total root length, chlorophyll content, leaf area, root surface area, root volume, root length, plant height, number of root tips, visible leaves, unfolded leaves, stem diameter, iron accumulation per plant, iron absorption efficiency and active iron content in leaves were significantly reduced and the average root diameter, root-shoot ratio and iron physiological efficiency of 32 maize varieties significantly increased under low iron stress, but there were differences among varieties. Cluster analysis of low iron effect value and two iron levels showed that under the same iron level, there were differences in the comprehensive performance of various traits of maize seedlings. Three iron-efficient varieties Zhenghong 2, Handan 999 and Quanyu 9, and three iron-inefficient varieties Chuandan 455, Chuandan 189 and Chengdan 30 were selected according to the comprehensive performance of two iron levels. Under low iron stress, the decrease of dry weight per plant, iron accumulation per plant, iron absorption efficiency and active iron content in leaves and the increase of root-shoot ratio of iron-efficient varieties were lower than those of iron-inefficient varieties, while the increase of iron physiological efficiency was higher than that of iron-inefficient varieties. Comprehensive analysis showed that iron-efficient varieties had stronger adaptability to low iron stress, and improving iron physiological efficiency is an important physiological mechanism for maize seedlings to adapt to low iron stress.