摘要： 以抗旱性不同的2个玉米品种为材料，研究了不同程度的水分胁迫对玉米生育中后期 根系及叶片的渗透调节能力、渗透调节物质的影响，比较了根系与叶片渗透调节的差异，结 果表明：拔节期、大喇叭口期、抽穗期、灌浆期叶片的渗透调节能力，随着水分胁迫的加剧 而增 强；不同的生育期比较，前3个生育期，随着生育进程渗透调节有增强的趋势，但灌浆期的 渗透调节能力下降；抗旱性强的品种渗透调节能力高于抗旱性弱的品种。根系的渗透调节能 力低于叶片。严重水分胁迫下根系的渗透调节能力从抽穗期开始下降，甚至低于中度水分胁 迫，2个品种的变化趋势基本相同。4种渗透调节物质可溶性糖、游离氨基酸、脯氨酸与K ＋的含量随着水分胁迫的加剧逐渐增加，但灌浆期较复杂。这可能与灌浆期大量的可溶 性 物质，特别是可溶性糖，用于子粒灌浆，灌浆与渗透调节物质竞争有关。根系无论渗透调节 物质的含量，还是渗透调节的增加量均小于叶片，与渗透调节的变化趋势一致。4种渗透调 节物质对渗透调节的相对贡献，在前3个生育阶段，以可溶性糖较多，其次是K⁺，但灌浆 期严重水分胁迫下游离氨基酸与脯氨酸对渗透调节的贡献增大。

关键词: 玉米, 水分胁迫, 渗透调节, 抗旱性

Abstract: Two maize (zea mays) varieties with different drought resistance were us ed to study the differences between leaves and roots in osmotic adjustment under water stress condition. The results were the osmotic adjustment (OA) of leaves became greater as the soil water content decreased in jointing, big bell and he adi ng stage, but it was smaller in the milk stage. The OA of the drought resistant va riety Luyu No.14 was greater than that of Yedan No.13 which is a drought sensiti ve variety. The OA of leaves was greater than that of roots. The OA of roots was s mall from heading stage under serious stress condition, and even became smaller than slight water stress condition. The concentrations of4 different solvable m atters, solute sugar, free amino acid, proline and K+ were increased as the so il wa ter content decreased. The levels of these solvable matters were lower in roots than in leaves, which was consistent with OA. The solute suger contributed more to O A, K⁺ was the second in slight stress condition, but the percentage of free ami no acid and proline increased under serious stress condition.

Key words: Zea mays, Osmotic adjustment, Drought res istance, Water stress