渗透胁迫下不同地理种源白刺的生理响应

Physiological responses of Nitraria tangutorum from different geographic provenances under osmotic stress

以武威、张掖、酒泉3个地理种源的唐古特白刺为研究对象,测定不同浓度PEG胁迫下白刺的相对含水量、丙二醛、脯氨酸、可溶性糖、可溶性蛋白及抗氧化酶等各生理指标的变化。结果表明,PEG渗透胁迫造成3个种源白刺相对含水量下降,丙二醛积累,同时超氧化物歧化酶活性上升,过氧化氢酶活性先升后降及脯氨酸、可溶性糖、可溶性蛋白含量增加,除了3个种源的超氧化物歧化酶活性与对照差异不显著外(P>0.05),其余指标与对照均差异显著(P<0.05)。从相关分析结果看出,3个种源白刺丙二醛与超氧化物歧化酶、脯氨酸、可溶性糖、可溶性蛋白均呈极显著相关,相对含水量与超氧化物歧化酶、可溶性蛋白、丙二醛、脯氨酸、可溶性糖均呈极显著负相关,脯氨酸、可溶性糖、可溶性蛋白、超氧化物歧化酶之间呈极显著或显著相关;主成分分析看出,白刺的第1主成分为相对含水量、膜脂过氧化产物丙二醛和渗透调节物质,第2主成分为超氧化物歧化酶,第3主成分为过氧化氢酶。在PEG胁迫下,3个地理种源白刺的耐旱性表现为酒泉种源>张掖种源>武威种源。

Nitraria tangutorum was taken from three geographic provenances（Wuwei,Zhangye and Jiuquan） and several physiological characteristics were measured under PEG stress.Under PEG osmotic stress,the contents of malondialdehyde（MDA）,proline（Pro）,soluble sugar（SS） and soluble protein（SP）,and superoxide dismutase（SOD） activity increased,while the relative water content（RWC） reduced and catalase（CAT） activity inbitially increased but then decreased.There were significant differences（P〈0.05） between PEG treatment and the control in most indexes,but not between SOD activity and the control.Correlation analysis showed that there were highly significant correlations of MDA content with SOD activity and with the contents of Pro,SP,and SS.There were highly significant negative correlations of RWC with SOD activity and with the contents of Pro,SP,SS and MDA.There were highly significant or significant correlations between SOD activity and the contents of Pro,SS and SP.Principal component analysis showed that the first principal components of N.tangutorum osmotic stress were RWC and the contents of Pro,SS,SP and MDA while the second and third were SOD and CAT,respectively.Under PEG stress,drought tolerances of plants from the three geographic provenances were in the sequence： Jiuquan〈Zhangye〉Wuwei.