Ecophysiological effects of multiple cropping of winter wheat-spring corn-summer corn in Huanghuaihai Plain Ecophysiological effect of xylem embolism in six tree species Ecophysiological effect of Medicago sativ L. biosphere coverage on young Camellia sinensis Kuntze garden Responses to Doubled CO2 in Medicago sativa: Studies on Ecophysiology and Simulation Modelling