Chlorophyll a Fluorescence Parameters of Flag Leaf of the Wheat and Seed Grouting under Different Water Treatments

Effect of water stress on the chlorophyll a fluorescence parameters of flag leaf of the wheat was studied with measuring result by OS30 chlorophyll fluorometer.The result indicated that the chlorophyll a fluorescence parameters of flag leaf were changed obviously under water stress.The decrease of the time from the point Fo to the point of 1/2 Fv(T1/2),the ratio of the variable to maximal fluorescence (Fv/Fm),the ratio of the variable to minimal fluorescence (Fv/Fo),variable fluorescence quenching rate(ΔFv/Fo)and Rfd(ΔFv/Ft)values under water stress suggested the primary light energy conversion of PSⅡ,the potential activities of PSⅡ,the potential photosynthetic activities and photosynthetic electron transport had been inhibited.Meanwhile effect of grouting rate of water stress was discussed.