Abstract:

In order to investigate the physiological characteristics of soybean under drought stress, a pot experiment was conducted to study the physiological and biochemical responses of soybean seedlings to drought stress. Four treatments were arranged: control (CK), light drought stress (L), moderate drought stress (M) and high drought stress (N). The results showed that: with the strengthening of drought stress, the chlorophyll content decreased, while the contents of free proline and soluble sugar significantly increased. Along with the period of drought stress continued, the MAD content showed a trend of up-down-up. SOD activity was tended to increase and then decreased. The water stress resulted in progressively decreases in net photosynthesis rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr), respectively, WUE increased a little under L and decreased to some extent under L, but obviously decreased under N. The intercellular CO2 concentration (Ci) decreased at light stress and moderate stress, but increased at high stress, which indicated that the decline of Pn was caused by stomatal restriction under light stress and moderate stress, but non-stomatal restriction under high stress.