Effect of Water Stress on the Photosynthesis and Fluorescence of Solidago canadensis

The effect of flooding stress and drought stress on the photosynthesis and fluorescence of Solidago canadensis was studied.The results showed that during a certain period of time,flooding stress accelerated the growth of plants,however,drought stress greatly suppress the growth of plants.During the 15 days' experiment,for flooding stress plants,the trends were embodied in the increasing value of chlorophyll,the ratio of lighting variable fluorescence to lighting maximum fluorescence(Fv'/Fm'),photosynthetic electron transport rate(ETR),photochemical quenching(qP)and net photosynthetic rate(NPR),the decreasing value of the minimum fluorescence(Fo),while the change of the ratio of variable fluorescence to maximum fluorescence(Fv/Fm)was not obvious;for drought stress plants,the trends embodied in the decreasing value of Chlorophyll,Fv/Fm,Fv'/Fm',ETR,qP and NPR,the increasing value of Fo,the plants were dead after treating 15 days.