Effect of potassium limitation on chlorophyll fluorescence parameters in rice leaves

The effects of potassium limitation on chlorophyll fluorescence parameters were investigated in rice leaves of potassium-sensitive cultivar Erjiufeng and potassium-insensitive cultivar Yuanfengzao respectively.The results showed that under the potassium limitation condition,the initial fluorescence value(F_o),the ratio of the variable to maximum fluorescence (F_v/F_m),and the non-photochemical quenching coefficient(NPQ) had no significant changes in both cultivars,as compared with the control.Whereas the ratio of the variable to maximum fluorescence in light(F′_(v)/F′_(m))、the photochemical quenching coefficient((q_(()_P))) 、the actual photochemical efficiency(Φ_(PSⅡ)),and the electron transport rate(ETR) decreased in both cultivars,especially in Erjiufeng.All these indicated that the effect of potassium limitation on chlorophyll fluorescence parameters is clearly related to the sensitivities of potassium deficiency in rice;and F′_v/F′_m、q_(()_P)、Φ_(PSⅡ) together with ETR may be applied to screen the tolerant cultivars rapidly.