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This study aims to investigate the protective roles of photosynthetic characteristics and antioxidative systems in the desiccation tolerance of Sophora moorcroftiana and Caragana maximovicziana as they adapt to arid environments. A variety of physiological and biochemical parameters in the leaves of two Leguminosae species were monitored for 1, 7, 14, 21 and 28 d of drought stress. Soil water content decreased from 38.58% to 7.33% after exposure to 28 d of water stress. The photosynthetic carbon-assimilation rates of the two Leguminosae plants decreased for non-stomatal limitation with processing water stress. The malondialdehyde content and cell membrane relative conductivity of the two species increased significantly from 1 to 21 d and then decreased. S. moorcroftiana showed higher superoxide dismutase and peroxidase activities than C. maximovicziana during the 28 d treatment period. However, the catalase activities and proline content of C. maximovicziana were higher than those of S. moorcroftiana before the water stress treatment reached 21 d. Nine physiological and biochemical parameters were selected to comprehensively evaluate the two species’ drought-resistance by the membership function values(MFV). The mean MFV indicated that S. moorcroftiana has a relatively stronger drought defense capability than C. maximovicziana. S. moorcroftiana mainly uses carbon-assimilation rate and osmotic adjustment to combat water deficiency.
This study aims to investigate the protective roles of photosynthetic characteristics and antioxidant systems in the desiccation tolerance of Sophora moorcroftiana and Caragana maximovicziana as they adapt to arid environments. A variety of physiological and biochemical parameters in the leaves of two Leguminosae species were monitored for 1, 7, 14, 21 and 28 d of drought stress. Soil water content decreased from 38.58% to 7.33% after exposure to 28 d of water stress. The photosynthetic carbon-assimilation rates of the two Leguminosae plants decreased for non-stomatal limitation with processing water stress. The malondialdehyde content and cell membrane relative conductivity of the two species increased significantly from 1 to 21 d and then decreased. S. moorcroftiana showed higher superoxide dismutase and peroxidase activities than C. maximovicziana during the 28 d treatment period. However, the catalase activities and proline content of C. maximovicziana were higher than those of S moorcroftiana before the water stress treatment reached 21 d. Nine physiological and biochemical parameters were selected to comprehensively evaluate the two species’ drought-resistance by the membership function values (MFV). The mean MFV showed that S. moorcroftiana has a relatively stronger drought defense capability than C. maximovicziana. S. moorcroftiana mainly uses carbon-assimilation rate and osmotic adjustment to combat water deficiency.