EFFECT OF CL- STRESS ON PHOTOSYNTHETIC, CHLOROPHYLL FLUORESCENCE CHARACTERS AND CHLOROPLAST ULTRA-STRUCTURE OF WATERMELON SEEDLINGS

The effect of chlorine ion stress on photosynthetic, chlorophyll fluorescence characters and chloroplast ultra-structure of watermelon seedling was studied in the research. The result showed: With the increased concentration of chlorine ion, the chlorophyll contents, net photosynthetic rate, potential quantum yield of photosystem II, quantum yield of PS II electron transport and photochemical quenching increased at lower concentrations (0.0-100 mmol·L -1 ) and decreased at higher concentration (150.0 mmol·L -1 ), but the transpiration rate, stomatal conductance, intercellular concentration and fluorescence origin were played down; The effect of chloroplast ultra-structure was smaller under lower concentrations (0.0∼50.0 mmol·L -1 ), but bigger effect was observed under higher concentrations (100.0-150.0 mmol·L -1 ), such as the change in the shape of chloroplast and size of starch grain, the damage of granum lamella, and the swelling of thylakoid.