中苜一号紫花苜蓿对混合盐和碱胁迫的生理响应

Physiological response of Zhongmu No.1 alfalfa to mixed salt and alkaline stress

摘要:

【目的】明晰中苜一号紫花苜蓿对混合盐和碱胁迫的生理响应。【方法】选用中苜一号紫花苜蓿为材料，以不同浓度盐和碱胁迫为变量，通过测定根苗比，相对含水量，叶绿素 a、叶绿素 b、叶绿素 a/b，丙二醛(MDA)，脯氨酸(Pro)和抗氧化酶活性变化 ，分析中苜一号紫花苜蓿抗盐和碱能力 。 【结果】1)随着盐浓度的增加，中苜一号紫花苜蓿相对含水量无明显变化；根苗比、MDA 含量、Pro、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性整体呈上升趋势，相比 CK 分别提高了 20. 00%、20. 21%、28. 76%、2. 35%、29. 31% 和 30. 00%；叶绿素 a/b 和过氧化物酶 (POD)整体呈下降趋势，叶绿素 a 和叶绿素 b 表现为“低促高抑”的特点。2)随着碱浓度的增加，中苜一号 MDA 含量 、Pro、SOD、POD 和 APX 活性整体呈上升趋势，较 CK 分别提高了 31. 70%、48. 29%、 10. 00%、27. 30% 和 75. 20%；相对含水量、叶绿素 a/b 和 CAT 活性整体呈下降趋势；根苗比、叶绿素 a 和叶绿素 b 含量呈先上升后下降趋势。3)中苜一号紫花苜蓿盐胁迫的平均隶属函数值为 0. 428，碱胁迫的平均隶属函数值为 0. 537。【结论】中苜一号紫花苜蓿幼苗对不同浓度的盐和碱胁迫都有一定的耐受力，且抗碱性大于抗盐性。

Abstract:

【Objective】 To clarify the physiological response of 'Zhongmu No. 1' alfalfa to mixed salt and alkalian stresses.【Methods】 'Zhongmu No. 1' alfalfa was selected as the material. The salt and alkali resistance of 'Zhongmu No. 1' alfalfa was analyzed by means of the determination of root/seedling ratios，relative water content，chlorophyll a，chlorophyll b，chlorophyll a/b，malondialdehyde (MDA)，proline (Pro) and antioxidant enzyme activities. 【Re‐ sults】1)With the increase of salt concentration，the relative water content of 'Zhongmu No. 1' alfalfa did not change significantly. The root/seedling ratios，the contents of MDA，Pro，Superoxide dismutase (SOD)，catalase (CAT) and ascorbate peroxidase (APX) showed an overall increasing trend，which increased by 20. 00%，20. 21%， 28. 76%，2. 35%，29. 31% and 30. 00% respectively compared with CK，. chlorophyll a/b and peroxidase (POD) showed an overall decreasing trend. Chlorophyll a and chlorophyll b showed a tendency of promotion in low concen‐ tration and inhibition in high concentration. 2)With the increase of alkaline concentration，the contents of MDA，Pro， SOD，POD and APX of 'Zhongmu No. 1' showed an overall increasing trend and increased by 31. 70%，48. 29%， 10. 00%，27. 30% and 75. 20%，respectively，compared with CK. While relative water content，the contents of chloro‐ phyll a/b and CAT showed an overall decreasing trend. The root/seedling ratios，the contents of chlorophyll a and chlorophyll b showed an increasing trend followed by a decreasing trend. 3)The mean affiliation function value of 'Zhongmu No. 1' alfalfa was 0. 428 for salt stress and 0. 537 for alkaline stress using the affiliation function method for comprehensive evaluation.【Conclusion】 Zhongmu No. 1 alfalfa seedlings had certain tolerance to salt and alkaline stress at different concentrations，and alkaline resistance is greater than salt resistance.