少花蒺藜草异型性种子人工老化过程中抗氧化生理响应差异

Differences in Antioxidant Physiological Responses of Heteromorphic Cenchrus pauciflorus Seeds during Artificial Aging

以少花蒺藜草(Cenchrus pauciflorus)异型性种子为实验材料,采用高温高湿人工老化的处理方法,测定了不同老化时间后种子发芽率和抗氧化酶活性。结果表明:随人工老化处理时间增加少花蒺藜草M型种子发芽率呈快速线性下降趋势,处理末期发芽率降至25%,而P型种子发芽率下降趋势平缓。超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性与未老化种子相比降幅达56%、19%和74%,而丙二醛(MDA)含量变化相反,处理期内呈上升趋势。异型性种子间生理响应存在显著差异,M型主要通过调控SOD和POD活性,P型种子主要通过调控CAT活性减少生理损伤,M型MDA含量高于P型。少花蒺藜草种子人工老化过程中,氧化损伤累积,种子逐渐失活,而异型性种子应对老化的生理响应特征差异意味着少花蒺藜草在繁殖输出时,能够在更大范围内适应外界环境变化,一定程度上为其成功入侵多种生境提供了生理基础。

The germination rate and antioxidant enzyme activities of heteromorphic Cenchrus pauciflorus seeds were measured after different aging times using artificial aging treatment at high temperature and high humidity.The results showed that the germination rate of M-type seeds of C.pauciflorus declined rapidly with increasing time of artificial aging treatment,reaching 25% at the end of the treatment,while the germination rate of P-type seeds decreased gradually.As compared to the control,the activities of the antioxidant enzymes superoxide dismutase(SOD),peroxidase(POD),and catalase(CAT) of aged seeds reduced by 56%,19%,and 74%,respectively.However,malondialdehyde(MDA) concentration altered in the opposite direction,rising over the treatment period.There were significant differences in physiological responses between heteromorphic seeds,with M-type mainly through regulation of SOD and POD activities,and P-type mainly through regulation of CAT activity to reduce physiological damage.M-type seeds also had greater MDA content than P-type seeds.During the artificial aging process of C.pauciflorus,the seeds accumulated oxidative damage,resulting in the inactivation of seeds.The differences in the physiological characteristics of heteromorphic seeds in response to aging implied that C.pauciflorus can adapt to external environmental changes on a larger scale during reproduction,providing a physiological basis for their successful invasion of various habitats.