【摘要】 在小幅度变化的低温条件下,研究抗寒性不同的紫花苜蓿根系和叶片中相关生理指标的变化规律,比较同一温度下不同品种间的差异性和同一品种在不同温度下的差异性。以此探讨抗寒性不同的紫花苜蓿对低温的响应差异,揭示紫花苜蓿抗寒性的机理,为紫花苜蓿品种的选育提供参考。结果表明:在同一温度处理下,抗寒性强的品种丙二醛含量低于抗寒性弱的品种,可溶性蛋白含量和可溶性糖含量高于抗寒性弱的品种。在-8℃处理下,4个供试品种根系和叶片中丙二醛含量差异显著(根系:F=7.683,p<0.05;叶片:F=15.016,p<0.05),抗寒性强的两个品种根系和叶片中丙二醛含量均显著低于抗寒性弱的品种。根系可溶性蛋白含量在-7℃(F=4.497,p<0.05)和-8℃(F=12.464,p<0.05)处理下均表现出品种间的显著差异,叶片可溶性蛋白含量在-6℃(F=5.891,p<0.05)和-7℃(F=6.921,p<0.05)处理下均差异显著。根系和叶片中可溶性糖的含量在-6℃(根系:F=113.593,p<0.05;叶片:F=61.481,p<0.05)、-7℃(根系:F=13.916,p<0.05;叶片:F=10.469,p<0.05)和-8℃(根系:F=90.890,p<0.05;叶片:F=29.040,p<0.05)3个低温处理下均表现出品种间的显著差异,抗寒性强的品种根系和叶片中可溶性糖的含量均显著高于抗寒性弱的品种。随着温度降低,抗寒性强的品种丙二醛含量上升幅度和可溶性蛋白下降幅度小于抗寒性弱的品种,可溶性糖上升幅度大于抗寒性弱的品种。综上所述,在低温胁迫下,抗寒性强的紫花苜蓿通过提高可溶性糖含量以及保持相对较高的可溶性蛋白含量来减少低温造成的伤害。更多还原

【Abstract】 Under the stress of low temperature with small fluctuations, MDA, soluble protein and soluble sugar contents and superoxide dismutase activity were studied in roots and leaves of 4 alfalfa varieties. The differences between varieties at the same temperature and the differences of the same variety at different temperatures were compared in order to reveal the differences and mechanisms of cold response of alfalfa with different cold resistances. The results showed that under the same low temperature treatment, MDA content in varieties with stronger cold resistance was lower than that in varieties with lower cold resistant, while soluble protein and soluble sugar contents were higher than those in lower cold resistant varieties. In the-8℃treatment, MDA contents in roots and leaves of the 4 tested varieties were significantly different(root: F=7.683, p<0.05; leaf: F=15.016, p <0.05), and the values in roots and leaves of the two varieties with stronger cold resistance were significantly lower than those of the varieties with lower cold resistant. The soluble protein contents in roots in-7℃(F=4.497, p<0.05) and-8℃(F=12.464, p<0.05) treatments were significantly different between varieties, leaf soluble protein content in-6℃(F=5.891, p<0.05)and-7℃(F=6.921, p<0.05) treatment were significantly different. The soluble sugar contents in leaves and roots in-6 ℃(root:F=113.593, p<0.05; leaf: F=61.481, p<0.05),-7℃(root: F=13.916, p<0.05; leaf: F=10.469, p<0.05) and-8℃(root: F=90.890, p<0.05; leaf: F =29.040, p <0.05) treatments were significantly different among varieties, and the soluble sugar contents of stronger cold resistant varieties in roots and leaves were significantly higher than those of lower cold resistance varieties. The increase range of MDA and the decrease range of soluble protein in stronger cold resistant varieties were smaller than those in lower coldresistant varieties, and the increase range of soluble sugar was higher than that in lower cold resistant varieties with the decrease of temperature. To sum up, under cold stress, cold resistant alfalfa can alleviate harm caused by low temperature through increasing soluble sugar content and keeping relatively high soluble protein content.更多还原