| 摘要: |
| 【目的】研究多年生黑麦草萌发期对低温与盐胁迫的交叉适应性，为在盐渍土壤上建植牧草提供依据。【方法】将多年生黑麦草种子在3～5 ℃低温条件下预处理3 d（T3）、5 d（T5）和7 d（T7），以未进行低温处理为对照（CK），并将4个处理组种子分别在质量分数为0%，0.3%，0.6%，0.9%和1.2%的NaCl溶液中进行萌发试验，测定种子的发芽指数、活力指数和幼苗的根系活力及丙二醛、脯氨酸、NO含量。【结果】随着NaCl质量分数的增加，各处理组多年生黑麦草种子的萌发均受到不同程度的抑制；T3与T5组种子的发芽指数、活力指数和根系活力间无显著差异，而两者总体上高于CK和T7组；各处理组幼苗丙二醛含量随着NaCl质量分数的增加总体呈上升趋势，但T7组丙二醛含量高于其他处理组；各处理组脯氨酸含量随NaCl质量分数增加均呈上升趋势，且CK组脯氨酸含量总体上高于各低温预处理组；各处理组幼苗的NO含量在NaCl胁迫下总体均呈上升趋势，但与质量分数0.3% NaCl胁迫相比，T5组幼苗NO含量在质量分数0.6%，0.9% NaCl胁迫下持续下降，CK、T3组在质量分数0.9% NaCl胁迫下的NO含量较质量分数0.6% NaCl胁迫时有所下降，CK、T3、T5组的NO含量均在质量分数1.2% NaCl胁迫下有较大幅度的上升，而T7组却在质量分数1.2% NaCl胁迫条件下略有下降。【结论】多年生黑麦草具有一定的耐盐性，低温预处理增强了其种子萌发期的抗盐胁迫能力；低温预处理3～5 d显著提高了种子萌发期的抗盐能力，黑麦草在低温和盐渍胁迫之间存在“交叉适应”现象，而NO可能作为二者的共同信号受体在交叉适应中发挥着调控作用。 |
| 关键词: 多年生黑麦草 萌发期 低温预处理 盐胁迫 交叉适应性 |
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| 基金项目:国家科技支撑计划项目2007BAK31B01-02B） |
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| Cross-adaptation of perennial ryegrass in germination stage to pre-chilling and salt stress |
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| Abstract: |
| 【Objective】The cross adaptation of perennial ryegrass in germination stage to pre chilling and salt stress was investigated for the establishment of grasses in saline soil.【Method】4 perennial ryegrass (Lolium perenne L.) seeds (3 were treated at 3-5 ℃ for 3 d（T3）,5 d（T5） and 7 d（T7）,and 1 was not treated (CK) ) were immersed in 0%,0.3%,0.6%,0.9% and 1.2% NaCl solution to germinate,respectively.Seed germination index,vitality index,the root vigor,and the contents of MDA,proline and nitric oxide（NO）in seedlings were measured.【Result】The germination of perennial ryegrass seeds in all treatments were inhibited by salt stress,and there was no difference in germination index,vitality index and root vigor between T3 and T5 treatments,both of them were higher than CK and T7 treatments.MDA contents in all treatments showed an increasing trend as salt stress increased,and the contents in T7 treatment were higher than in others.Proline contents in all treatments showed an increasing trend as salt stress increased,but the contents in pre chilling treatments were lower than that in CK.There was no difference in the proline contents between T3 and CK treatments,and they were higher than in T5 and T7 treatments.NO contents in all treatments showed an increasing trend as salt stress increased.Comparing with the NO content in T5 treatment at 0.3% NaCl,the content continually declined at 0.6%,0.9% NaCl.Comparing with the NO contents in CK and T3 treatments 0.6% NaCl,the contents declined.The NO contents in CK,T3,T5 treatments increased at 1.2% NaCl,but the NO content in T7 treatment decreased at 1.2% NaCl.【Conclusion】Perennial ryegrass had a certain salt tolerance and pre-chilling increased its salt tolerance in germination stage.Pre chilling for 3-5 d increased the salt tolerance in germination stage.“Cross adaptation” between pre-chilling and salt stress was observed in germination stage of perennial ryegrass seeds and NO might have regulatory effect on the cross-adaptation as a signal receptor for both pre-chilling and salt stress. |
| Key words: perennial ryegrass germination pre-chilling salt stress cross-adaptation |
