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采用人工模拟融冻胁迫方法,通过测定白三叶(Trifolium repens)和红三叶(T.prat-ense)在融冻胁迫中叶片细胞膜透性、MDA含量、抗氧化酶(SOD、POD、CAT)活力、渗透调节物(脯氨酸、可溶性糖和蛋白质)含量变化,以揭示未来气候变化对三叶草的影响。结果表明,经历融冻胁迫循环后抗冻力强的白三叶植株能恢复生长,而抗冻力弱的红三叶枯萎死亡。在融冻阶段,两三叶草叶片细胞膜透性增大、抗氧化酶活力增高、MDA和渗透调节物含量大幅增加;在冻融阶段,两三叶草叶片细胞膜透性降低、MDA含量下降、抗氧化酶活力降低。但在融冻胁迫循环中,白三叶叶片POD和CAT活力高于红三叶,脯氨酸含量较红三叶高5倍,但细胞膜透性低于红三叶。白三叶在-5℃抗逆生理指标达到最大值,而红三叶在-10℃。白三叶对环境温度变化反应敏感,在-5℃通过快速激活抗氧化酶系统和积累渗透调节物以抑制膜脂过氧化和维护细胞水分平衡在融冻适应上起重要作用。白三叶具有较强的抗融冻能力,是未来值得应用推广的优良园林绿化植物。
By artificial freezing and thawing method, the cell membrane permeability, MDA content, antioxidant enzymes (SOD, POD, CAT) in the thawed leaves of Trifolium repens and T. prat-ense ) Vitality, osmotic adjustment (proline, soluble sugar and protein) content changes in order to reveal the impact of future climate changes on clover. The results showed that the white clover plants with strong frost resistance could resume growth after the freeze-thaw cycles, while the red clover with weak frost resistance died. In the thawing stage, the cell membrane permeability of two-leaf clover increased, antioxidant enzyme activity increased, MDA and osmotic regulator content increased significantly. During the freeze-thaw period, the cell membrane permeability decreased, the MDA content decreased and the antioxidant enzyme activity reduce. However, the activities of POD and CAT in white clover leaves were higher than those in red clover leaves during prolongation of thawing, and the content of proline was 5 times higher than that of red clover leaves, but the membrane permeability was lower than that of red clover leaves. White clover at -5 ℃ physiological indicators to reach the maximum, while the red clover at -10 ℃. White clover is sensitive to changes in ambient temperature and plays an important role in freeze-thaw adaptation by rapidly activating the antioxidant enzyme system and accumulating osmoregulators at -5 ° C to inhibit membrane lipid peroxidation and maintain cellular water balance. White clover has a strong anti-thawing ability, is worth promoting the application of good landscaping plants.