后期高温对冬小麦根系及地上部衰老的影响

Effects of High Temperature on the Senescence of Root and Top-partial of Wheat Plant in the Later Stage

本文研究了后期高温处理对冬小麦根系及地上部活性代氧代谢及生理特性的影响。结果表明,高温处理使小麦根系及叶片的膜脂过氧化产物MPA含量增加,质膜相对透性增大。在高温处理过程中,根系和叶片SOD及POD酶活性的变化均表现为先升高而后下降的趋势,但叶片SOD和POD活性下降较早,其下降幅度亦大于根系,表明地上部受高温影响较大。小麦根系及叶片的膜脂过氧化水平与SOD和POD酶活性的变化有密切关系,随叶片SOD和POD酶活性下降,膜脂过氧化加剧,细胞质膜相对透性增大,当根系SOD、POD酶活性下降时,细胞质膜结构遭严重破坏,生理功能明显衰退。

Effects of high temperature on metabolism of active oxygen and physiological characteristics of wheat root and leaves were studied in 1985~1987. The result indicated that temperature over 38℃ increased the MDA content and the membrane permeability of root sys tem and leaves of wheat. The activities of both SOD and POD of leaves and root system were en hanced during the early stage of high temperature treatment, and then dropped as the time went on. Earlier and greater dropping of SOD and POD activity in leaves than that in root system showed that the top-partial of the plant was more sensitive to the high temperature. The mem brane lipid peroxidation was found related to the changes of SOD and POD. The permeability of plasm membrane and the MDA content increased obviously when the activity of SOD and POD in leaves dropped. The structure of the plasma membrane was destroyed seriously, and the physio logical function declined sharply when the activity of SOD and POD of root system dropped.