title: Physiological responses of three soybean species (Glycine soja, G. gracilis, and G. max cv. Melrose) to salinity stress.
abstract: Understanding the mechanism for salt tolerance in wild soybean (Glycine soja) can help researchers improve that trait in cultivated soybean lines. We analyzed the effects of excess NaCl on the growth, physiology, and ion distribution in three soybean species: wild G. soja (W8), semi-wild G. gracilis (SW18), and the cultivated salt-sensitive G. max (cv. Melrose). These comparisons revealed that, under salt stress, shoot and root lengths and biomass (either shoot or root dry weights) were significantly higher for the W8 genotype than for the other two. Most of the morphological parameters for roots from the W8 plants were also increased, including total length, specific root length, and surface area. However, the average root diameter for W8 was significantly lower than that of either SW18 or 'Melrose' soybeans. In response to salinity, photosynthesis was suppressed to a greater extent in 'Melrose' than in W8. The relatively higher tolerance shown by W8 plants was also associated with lower levels of malondialdehyde, hydrogen peroxide, and relative electrical conductivity, but higher activities by superoxide dismutase and peroxidase, as well as more free proline and glycine betaine. In addition, the W8 plants contained less Na+and Cl-, but more K+, and they had a higher K+/Na+ratio in their leaves and roots when compared with either SW18 or 'Melrose' plants. Therefore, the W8 genotype performs better in terms of seedling growth, photosynthetic characteristics, and physiological indexes. These findings provide guidance for developing new soybean cultivars with improved tolerance to salt stress. Our data also contribute to the knowledge base for plant salt tolerance as a tool for increasing the yields of other crops in high-salinity soils.
authors.affiliation: College of Life Sciences, Hebei University, Baoding, 071002, China.
authors.forename: Haoran
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Plant Protection, College of Agriculture and Forestry, Hebei North University, Zhangjiakou, 075000, Hebei, China.
authors.forename: Jinhui
authors.initials: J
authors.lastname: Song
authors.affiliation: College of Life Sciences, Hebei University, Baoding, 071002, China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Dong
authors.affiliation: College of Life Sciences, Hebei University, Baoding, 071002, China.
authors.forename: Di
authors.initials: D
authors.lastname: Wang
authors.affiliation: College of Life Sciences, Hebei University, Baoding, 071002, China. zslhealth@126.com.
authors.forename: Shuling
authors.initials: S
authors.lastname: Zhang
authors.affiliation: College of Life Sciences, Hebei University, Baoding, 071002, China. jianfengliu@hbu.edu.cn.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Liu
mesh_terms: D018556:Crops, Agricultural; D006861:Hydrogen Peroxide / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D010788:Photosynthesis; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D054712:Salinity; D055049:Salt Tolerance; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D012965:Sodium Chloride / Q000494:pharmacology*; D013025:Glycine max / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D013312:Stress, Physiological; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D012965:Sodium Chloride; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase
keywords: Photosynthetic parameters; Physiological indexes; Plant growth; Salt stress; Soybean