Abstract:
The Nephrolepis cordifolia L.was used as test material.The effects of kinetin(KT) solution with different concentrations 5,7.5,10 μmol·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.