The Tolerance of Different Energy Willow’s Clones to Soil Cd Contamination Tolerance of Three Energy Willow‘s Clones to Heavy Metal Pb Physiological Responses of Four Energy Willow Clones to Soil Hg2+ Stress Physiological Responses of Different Energy Willow Clones under Drought Stress Impact of Different Salinity Habitats on the Growth of Energy Willow Clones in Tianjin Physiological responses of different willow’s clones to NaCl stress