Effects of Drought Stress on Growth and Chlorophyll Fluorescence Parameters of Typha orientalis

Field surveys were carried out to explore effects of soil moisture on morphology,biomass,chlorophyll content and chlorophyll fluorescence parameters of Typha orientalis.Results show that(1) soil water content significantly affected plant height of T.orientalis,which was 90.90%,68.19% and 63.64% of that in the control group(soil water saturation),when the plants were exposed to light,moderate and heavy drought stress,respectively;(2) stem diameter,leaf length,leaf width and chlorophyll content in the leaf decreased with the decreasing soil moisture content,while percentage of withered leaves significantly increased;(3) treatments different in soil moisture content differed sharply(P0.05) in density and biomass of T.orientalis,and density of the plants decreased by 41.67%,53.33% and 66.67% in the treatment of light,moderate and heavy drought stress,respectively,while biomass of a single plant in the control was 2.25,5.54 and 7.45 times that in the treatment of light,moderate and heavy drought stress,respectively;and(4) the maximum quantum yield of the leaves(Fv/Fm) and maximum electron transport rate(Re,t,max) decreased significantly with the decreasing soil moisture content;and drought reduced photochemical efficiency of the PSⅡ of leaves,thus inhibiting the growth of T.orientalis.