Abstract: The impacts of drought on agricultural production is a hot topic in agrometeorological research field. Soybean is an important economic crop. Clarifying its responses and adaptation characteristics to drought would be helpful to predict the soybean yields and improve agricultural production technology under global climate change. Therefore, authors conduct water control experiments in the scientific observing and experimental station of crop cultivation in northeast China. The soybean cultivar "Liaodou 15" was used and the drought and rewatering control experiments were conducted. At the flowering and full seed stage, the light drought (relative soil moisture 65%±5%), heavy drought (relative soil moisture 50%±5%), and control (relative soil moisture 80%±5%) treatments were set, respectively and the treatments lasted for 7, 14 and 21 days, respectively. After the droughts, the rewatering treatments were conducted to make the relative soil moisture recover to the control level. When the water stress reached the set levels, the indexes including contents of soluble protein, malondialdehyde (MDA) and the activities of superoxide dismutase (SOD) and peroxidase (POD) in the leaves were measured. These indices were also measured on the seventh day after rewatering to clarify the effects of drought and the compensation effects of rewatering. The results showed that the contents of soluble protein, malondialdehyde (MDA) and the activity of peroxidase (POD) increased significantly under light and heavy drought conditions at the flowering stage. The activity of superoxide dismutase (SOD) increased significantly under light drought condition. At the full seed stage, the soluble protein content, MDA content and SOD activity increased, but the POD activity decreased significantly. Rewatering showed compensation effects on soluble protein content, MDA content and SOD activity of soybean leaves, but did not show obvious compensation effect on POD. In conclusion, drought would probably induce peroxidation damage to soybean leaves, represented by the increase of antioxidant enzyme and osmotic regulation substance content. Rewatering can alleviate the peroxidation damage caused by drought, showing different degrees of compensation effect.

Key words: Soybean, Drought stress, Rewatering, Physiological and biochemical indexes, Compensation effect