Comparative Study of the Effects of Four Divalent Metal Chlorides on the Physiological Parameters of Maize Seedlings Preliminary study on water parameters of Populus euphratica and P.pruinosa by using P-V curve RESPONSES OF PHOTOSYNTHESIS AND PV-PARAMETERS TO WATER STRESS IN POPLAR CLONE SEEDLINGS The change of water parameters in Tetraena mongolica with season and habitat DROUGHT RESISTANCE INDEX OF 6 TREE SPECIES IN THE LOESS REGION Analysis of Water Management Strategy for Larix gmelinii Study on the water physio-ecological characteristics of Populus beijingensis