Abstract:

We examined effects of exogenous nitric oxide derived from a donor of 10～50 mg·L^-1 sodium nitroprusside (SNP) on detached leaves of Shibataea chinensis after anthesis.The results showed that: decreases of leaf chlorophyll and protein content were alleviated to different degree when the isolated leaf was pretreated with different concentrations of SNP solution, among which the 30 mg·L^-1 SNP had the best effect. Compared to control, the detached leaf SOD and POD activity were respectively decreased by 26.2% and 35.6%, maximum fluorescence of dark adaptation (F_m), PSⅡ maximal photochemical efficiency (F_v/F_m), and PSⅡ potential activity (F_v/F_o) were respectively decreased by 42.1%，38.2%，77.0%, but the minimum fluorescence of dark adaptation(F_o) was increased 89.5% after 5 d treatment. However, after the pretreatment with 30 mg·L^-1 SNP, the changes of all the above physiological parameters were inhibited significantly. The results demonstrated that proper concentration of exogenous nitric oxide was able to slow down efficiently the senescence process of detached leaves of S. chinensis after anthesis.

Key words: nitric oxide, Shibataea chinensis, detached leaf, senescence, chlorophyll fluorescence