低温胁迫对野生狗牙根选系生理生化特征的影响

Impacts of Low Temperature Stress on Physiological and Biochemical Characteristics in Merit Accessions of Cynodon dactylon

[目的]为筛选抗寒优异材料、选育抗寒品种提供理论依据。[方法]以国外引进的狗牙根品种Tifway材料为对照,研究连续9 d的低温(5℃/-5℃,昼夜)胁迫下Sau02011、Sau9934、Sau9928和Sau9926四份野生狗牙根选系代谢、生化、理化等指标的响应。[结果]在低温胁迫下,野生狗牙根选系的叶绿素含量降低,相对电导率、丙二醛含量、游离脯氨酸含量升高,而保护酶SOD活性呈现先升高后降低的趋势。狗牙根材料对低温胁迫表现出积极的响应,但随着胁迫时间的延长,各狗牙根材料也受到一定的伤害。[结论]Sau02011和Sau9926在低温胁迫下叶绿素损伤较小,相对电导率与MDA含量增加幅度较小,而保护酶SOD活性较大。它们是极具抗寒潜力的优良狗牙根选系。

[Objective] To provide theoretical basis for selecting merit cold-tolerance accessions and varieties breeding.[Method] With the variety of Tifway introduced from foreign country as the control,the physiological and biochemical characteristics of four accessions（including Sau02011,Sau9934,Sau9928 and Sau9926） under continuously low temperature stress（5 ℃/-5 ℃） for nine days were studied.[Result] Under the low temperature stress,contents of the total chlorophyll in all Cynodon accessions decreased,leaf relative electric conductivity rates and contents of MDA and free proline increased,while SOD activites increased first and then decreased.All Cynodon accessions responded actively under low temperature stress,and continuous low temperature induced injury to them to some extent.[Conclusion] Because of their rather high chlorophyll contents,lower increments of relative electric conductivity rates and contents of MDA,and higher SOD activites under low temperature stress,Sau02011 and Sau9926 were two excellent accessions with stronger cold-tolerance.