外源亚精胺对干旱胁迫下玉米幼苗叶片生理及根系特征参数的影响

采用营养液水培法,以两种不同耐旱类型玉米品种先玉335(抗旱性强)和丰禾1号(抗旱性弱)为试验材料,研究了利用20%聚乙二醇(PEG-6000)模拟的干旱胁迫下根施外源亚精胺(Spd,0.1 mmol/L)对玉米幼苗干(鲜)重、根系特征(根长、根表面积、根体积)、叶片相对含水量、叶绿素含量及细胞膜透性的影响。结果表明:正常条件下,外源Spd处理可显著提高两个玉米品种的干(鲜)重、株高、根长及根表面积,但对根体积、根平均直径、叶片相对含水量、叶绿素含量及细胞膜透性的影响较小。干旱胁迫下,外源Spd处理可显著提高玉米幼苗干(鲜)重、叶片相对含水量和叶绿素含量;增加根系数量,且随0~1.0 mm径级比例根系数量的增加,其根系长度增加幅度相应加大,随0.5~1.5 mm径级比例根系数量的增加,其根系表面积增加幅度相应加大;使玉米幼苗叶片细胞膜透性显著降低;对抗旱性弱的丰禾1号影响更为明显。因此,适宜浓度的外源Spd可以减轻干旱胁迫对玉米幼苗的伤害,并能更好地缓解干旱胁迫对抗旱性弱的玉米品种生长的抑制作用。

Effects of exogenous spermidine on leaf physiologic and root feature parameter of maize seedling under drought stress

Effects of exogenous spermidine application(0.1 mmol/L) on plant growth, root feature parameters(root length, root surface, root volume etc.), relative water content of leaf, chlorophyll contents and membrane permeability in seedlings of maize cultivar ‘Xianyu 335’(drought-tolerant) and ‘Fenghe No.1’(drought-sensitive) under drought stress induced by 20% polyethylene glycol 6000 were investigated by hydroponic experiments. The results showed that exogenous spermidine significantly increased the fresh and dry weight, plant height, root length and root surface of both maize seedlings, but only slightly affected the root volume, average root diameter, relative water content of leaf, chlorophyll contents and membrane permeability under normal condition. When under drought stress, exogenous spermidine treatment could lead to a marked increase in fresh and dry weight, plant height, relative water content and chlorophyll contents of leaf, increase the number of roots, with the increase of the number of roots of 0-1.00 mm diameter class, the increase of root length corresponding to is large, and with the number of roots of 0.50-1.50 mm diameter class increases, the corresponding increase of the surface area is great, and decrease leaves membrane permeability of maize seedlings. The effect of exogenous spermidine on anti-aging was more obvious in drought-sensitive Fenghe No.1 than in Xianyu 335 maize variety. The results suggested that appropriate amount of exogenous spermidine could lighten the drought stress damage and alleviate the growth inhibition of drought-sensitive maize variety.