PEG干旱胁迫对红三叶抗性生理生化指标的影响研究

Study on the Effects of PEG Stress on Physiological and Biochemical Indexes of Five Red Clovers

为快速比较红三叶(Trifolium pretense)植株抗旱性,采用不同浓度PEG-6000溶液对4个野生红三叶材料和1个红三叶品种进行不同程度的水分胁迫处理,研究不同水分胁迫对各材料叶片中生理生化指标的影响。结果表明:不同PEG干旱胁迫处理下,巫溪红三叶叶片含水量降幅较低,20%PEG处理下与对照相比下降幅度为28.49%,叶片电导率均最低,为对照的2.78倍,MDA含量增幅较小,为对照的2.84倍,叶片细胞膜系统有较强的抗旱能力;而红三叶06-4叶片含水量降幅最大,在强度渗透胁迫下与对照相比下降幅度为35.32%,叶片电导率在20%PEG处理时为对照5.01倍,MDA含量增幅最大,为对照的4.24倍,其忍耐干旱的性能相对较弱。渗透胁迫下各品种叶片游离脯氨酸含量显著增加,当PEG浓度为20%时,巫溪红三叶脯氨酸含量急剧上升,为对照的30.84倍。红三叶各材料的SOD活性在轻度干旱胁迫时均提高,胁迫程度增强时SOD活性下降。PEG胁迫导致红三叶各材料叶片相对含水量下降、细胞膜透性增大、MDA含量上升、脯氨酸含量增加而SOD活性下降,但4个材料和1个红三叶品种对应指标的变化幅度存在差异,巫溪红三叶表现出较强的抗旱性,而‘红三叶06-4’抗旱性较弱。

In order to compare the Red clover(Trifolium pretense) drought resistance,the effects of PEG stress on physiological and biochemical indexes of four Red clover accessions and one Red clover variety leaf were investigated under treatments with different PEG concentrations.Wuxi Red clover,with the higher relative water content and least decreasing changes,a decline of 28.49% compared with the control,the lowest electrical conductivities,increased by 2.78 times compared with the control,and the smallest increasing rates of MDA contents,increased by 2.84 times compared with the control under 20% PEG stress had more tolerant membrane systems and was the most resistant to osmotic stress,while Red clover 06-4 was relatively weaker resistant.Proline accumulation in leaves of five red clovers had the strongest resistance under PEG stress,and proline accumulation content of Wuxi Red clover was 30.84 times to the control group.SOD activities in leaves of five accessions increased during the initial stress stage at 5% PEG concentration and decreased continuously under severer stress.PEG stress resulted in the decreases in leaf relative content and increases in leaf cell membrane permeability,MDA content and praline accumulation of five Red clover wild accessions.SOD activities decreased continuously under severer stress.There was difference in the changing extents of the corresponding indices among five Red clovers.Red clover Wuxi was the most resistant to osmotic stress,while the resistance of Red clover 06-4 was the weakest.