激动素对肾蕨切叶活性氧代谢及抗氧化系统的影响

Effects of Kinetin on Reactive Oxygen Species Metabolism and Antioxidant System in Cut Foliage of Nephrolepis cordifolia L.

以肾蕨为试材,采用瓶插的方式,研究了激动素(KT)溶液[5、7.5、10μmol·L^(-1)(KT5、KT7.5、KT10)]作为瓶插液对肾蕨切叶活性氧代谢及抗氧化系统的影响,以期阐明激动素延缓肾蕨切叶衰老的机理。结果表明:瓶插12 d后,与对照(去离子水瓶插)相比,KT10处理的切叶过氧化氢、超氧阴离子和丙二醛含量以及电导率均降低,分别降低了92.06%、20.72%、410.34%、104.40%,其次为KT7.5(-46.46%、-18.09%、-173.39%、-59.93%)和KT5(-23.69%、-13.40%、-63.58%、-37.39%),说明KT可以抑制活性氧的产生,维持细胞膜的完整性及稳定性。KT10瓶插提高了超氧化物歧化酶(SOD)(19.32%)和过氧化氢酶(CAT)(86.36%)活性,其次为KT7.5,增加了13.37%和42.42%,KT5瓶插仅增加了7.76%和31.82%。同时,KT10处理还通过维持抗坏血酸过氧化物酶(APX)(225%)、谷胱甘肽还原酶(GR)(366.67%)、脱氢抗坏血酸还原酶(DHAR)(566.67%)活性来维持AsA-GSH循环的平衡,降低了总抗坏血酸(-442.12%)和总谷胱甘肽(-27.90%)含量,缓解了氧化损伤。KT7.5和KT5也在一定程度上维持AsA-GSH循环的平衡。总之,激动素能通过抑制活性氧含量、维持膜稳定性、激活抗氧化防御机制以及平衡AsA-GSH循环,有效延缓切叶的衰老,而抗衰老的效果为KT10>KT7.5>KT5。

The Nephrolepis cordifolia L.was used as test material.The effects of kinetin(KT)solution with different concentrations[5,7.5,10μmol·L^(-1)(KT5,KT7.5,KT10)]on the vase life,reactive oxygen species metabolism and antioxidant system of cut foliage of Nephrolepis cordifolia L.were studied,in order to clarify the mechanism of kinetin delaying the senescence of cut foliage of Nephrolepis cordifoliaL..The results showed that after 12 days in vase,compared with control(deionized water,CK),the contents of hydrogen peroxide,superoxide anion and malondialdehyde and the electrical conductivity of cut leaves treated with KT10 were decreased by 92.06%,20.72%,410.34%and 104.40%,respectively,followed by KT7.5(-46.46%,-18.09%,-173.39%,-59.93%)and KT5(-23.69%,-13.40%,-63.58%,-37.39%).These results showed that KT could inhibit the production of reactive oxygen species and maintain the integrity and stability of cell membrane.KT10 increased the activities of superoxide dismutase(19.32%)and catalase(86.36%),while KT7.5 increased by 13.37%and 42.42%,and KT5 increased by 7.76%and 31.82%,respectively,and both of them reduced the toxic effect of reactive oxygen species.meanwhile,KT10 treatment also maintained the balance of AsA-GSH cycle by increasing the activities of ascorbate peroxidase(225.00%),glutathione reductase(366.67%)and dehydroascorbate reductase(566.67%),and decreasing the activity of total ascorbate(-442.12%),glutathione(-27.90%),alleviated oxidative damage.KT7.5(-134.17%,-15.30%)and KT5(-65.94%,-11.82%)also decreased the content of ascorbate and glutathione to varying degrees.In conclusion,kinetin could effectively retard leaf senescence by inhibiting reactive oxygen species content,maintaining membrane stability,activating antioxidant defense mechanism and balancing the AsA-GSH cycle,and the KT10 had the best anti-senescence effect,followed by KT7.5,and the KT5 had the lowest effect.