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两个抗旱力不同的苜蓿品种在水分供应充分情况下,叶片和根系中过氧化物酶(POD)同工酶谱带数目相同,均为四条,但抗旱性较强的定西苜蓿酶带峰形高于抗旱性较弱的天水苜蓿。随着PEG渗透胁迫强度增加,定西苜蓿叶片POD同工酶G_s带活性增强,G_1带活力一直维持较高,而天水苜蓿则相反。前者根系在10％PEG处理时产生一条新带,后者则无新带产生。定西苜蓿叶片和根系中过氧化氢酶(CAT)同工酶谱带数目(9、11)多于天水苜蓿(7、9)。从而得出结论,不同器官对干旱的反应不同,叶片以增强POD的特定同工酶酶活性,根系则以改变酶谱,亦即改变基因表达来适应渗透胁迫。而叶中CAT同工酶谱的变化和根中CAT同工酶谱的稳定性似乎也与不同品种苜蓿适应渗透胁迫环境有一定的关系。
Two alfalfa cultivars with different drought tolerances had the same number of peroxidase (POD) isozyme bands in leaves and roots under the condition of adequate water supply, Higher than drought-resistant Tianshui alfalfa. With the increase of PEG osmotic stress, POD isoenzyme G_s band activity increased, while G_1 band vigor remained higher, while that of Tianshui alfalfa was the opposite. The former produced a new band at 10% PEG treatment and the latter no new band. The number of catalase bands in leaves and roots of Dingxi alfalfa was higher than that of Tianshu alfalfa (7,9). It was concluded that different organs responded differently to drought. Leaves were used to enhance specific isoenzyme activities of POD while root systems were adapted to osmotic stress by altering the enzyme profile, ie, changing gene expression. However, changes of CAT isozymes and CAT isozymes in roots also seemed to be related to the adaptability of different varieties of alfalfa to osmotic stress.