Adaptive Variations for Salt Tolerance in Mineral Content and Photosynthetic Characteristics in Different Evolutionary Types of Soybean

This study was conducted to determine the differences and changes in trends of physiological metabolism in the process of adaptation to saline environments and artificial domestication among the subgenus Soja. Glycine max, Glycine gracilis and Glycine soja were used as the experimental material. The determination of mineral contents during different growth periods and the photosynthetic pigments, gas exchange parameters and soluble carbohydrate contents in the initial bloom stage were investigated. The results showed that, NO3 , H2PO4, Cu, Zn and B contents and the photosynthetic pigments, gas exchange parameters and photosynthetic product were significantly higher in salt-tolerant wild soybean than in common wild soybean. NO3 , H2PO4 , SO4, K, Mg, Fe, Cu, Mo and Mn contents were significantly lower in cultivated soybean than in common wild soybean; and Ca and B were significantly higher. The photosynthetic pigments, gas exchange parameters and photosynthetic product at the initial bloom stage in cultivated soybean were significant higher than in common wild soybean and semi-wild soybean. The correlations of H2PO4, SO4, K, Mg, Mo and Mn with photosynthetic characteristic parameters significantly differed among members of Soja. Our study confirmed that mineral contents and photosynthetic characteristics among Soja had evolved towards the different environments and human requirements during long-term natural selection and artificial domestication. These findings will contribute to understanding the evolutionary trend of soybean.