MgCl2及MgSO4胁迫对紫花苜蓿幼苗生理的影响

Effects of MgCl2 and MgSO4 stress on physiology of alfalfa seedlings

摘要:

【目的】 探索MgCl2 、MgSO4 胁迫对紫花苜蓿生理的影响。【方法】 以中苜1号紫花苜蓿幼苗为试验材料，设置200 mmol/L MgCl2 、MgSO4 模拟中性盐胁迫，研究中苜1号在盐胁迫0、3、6、24 h的生理变化趋势。【结果】 随着胁迫时间的延长，MgCl2 胁迫下中苜1号幼苗叶绿素（Chl）、丙二醛（MDA）、可溶性糖（SS）、可溶性蛋白（SP）含量及过氧化物酶（POD）活性均呈现先上升后下降的趋势。其中，胁迫 3 h时，幼苗内Chl、MDA和SP含量达到最大值，均与CK间存在显著性差异，分别比CK上升了 57. 06%、56. 77%和138.95%，胁迫6 h时，幼苗内SS含量和POD活性达到最大值，均与CK间存在显著性差异，分别比CK上升了352.13%和86.41%；在MgSO4 胁迫下苜蓿叶片内SS、SP含量和POD活性均呈现先上升后下降的趋势，其中，胁迫3 h时，幼苗内SP和POD活性达到最大值，幼苗内SP含量与CK间存在显著性差异，而POD含量与CK间差异不显著，与CK相比，分别上升了115.88%和 15. 48%，胁迫6 h时，幼苗内SS含量达到最大值，与CK间存在显著性差异，SS含量上升了1175.64%， 而CC和MDA的含量呈现逐渐上升的趋势，在胁迫24 h，Chl和MDA含量达到最大值，均与CK间存在显性差异，分别比CK上升了251.72%和382.71%。利用隶属函数法对两种盐胁迫下中苜1号幼苗内不同生理指标进行综合评价得出，中苜1号紫花苜蓿MgCl2 胁迫的平均隶属函数值为0.51，MgSO4 胁迫的平均隶属函数值为0.49。【结论】 中苜1号幼苗对两种盐的耐受性由强到弱为MgCl2 ＞MgSO4. 。

Abstract:

【Objective】 To explore the effects of MgCl2 and MgSO4 stresses on physiological indexes of alfalfa. 【Method】Using Zhongmu No. 1 alfalfa seedlings as experimental materials，200 mmol/L MgCl2 and MgSO4 were set to simulate the neutral salt stress，and the physiological changes of Zhongmu No. 1 at 0，3，6 and 24 h of salt stress were studied.【Result】 The results showed that with the extension of stress time，the contents of Chl，MDA，SP，SS and POD activity in Zhongmu No. 1 seedlings increased first and then decreased under the stress of MgCl2 ，and the contents of Chl，MDA and SP in seedlings reached the maximum value at 3 h stress，all of them are significantly dif ferent from CK，compared with CK，they increased by 57. 06%，56. 77% and 138. 95%，respectively. At 6 h of stress，the SS content and POD activity in seedlings reached the maximum，which were significantly different from those of CK，and increased by 352. 13% and 86. 41%，respectively. Under the stress of MgSO4 ，the contents of SS and SP and the activity of POD in alfalfa leaves all showed a trend of first increasing and then decreasing. At 3 h stress，SP and POD activities in seedlings reached the maximum value，and SP content in seedlings was significantly different from CK，while POD content in seedlings was not significantly different from CK，and increased by 115. 88% and 15. 48% respectively compared with CK. At 6 h stress，SS content in seedlings reached the maximum value，which was significantly different from CK. The content of SS increased by 1175. 64%，while the content of Chl and MDA showed a gradual upward trend. At 24 h of stress，the content of Chl and MDA reached the maximum， which showed dominant differences with CK，and increased by 251. 72% and 382. 71%，respectively，compared with CK. The membership function method was used to comprehensively evaluate different physiological indexes in the seedlings of Zhongmu No. 1 under two salt stresses. The average membership function value of Zhongmu No. 1 al falfa under MgCl2 stress was 0. 51，and the average membership function value of Zhongmu No. 1 under MgSO4 stress was 0. 49.【Conclusion 】 The tolerance of Zhongmu No. 1 seedling to two kinds of salt was in the order from strong to weak： MgCl2 ＞ MgSO4 .