The plastic response of Bassia dasyphylla (Fisch. & C.A. Mey.) Kuntze functional traits to saline-alkali land habitat and its mechanism were investigated. Two neutral salts, NaCl and Na2SO4, and two alkalisalts, Na2CO3 and NaHCO3, were mixed in various ratios according to the varying ranges of salinity and pHin a natural soil, and the response of B. dasyphylla seedlings to salt-alkaline stress was determined. Theosmolyte contents, peroxidative damage, antioxidant enzyme activity and plant morphology and biomasswere determined. Thirty different salt-alkaline ecological treatments were applied, including ranges of salin-ity of 50-250 mmol/L and pH values of 7.10-10.19. The soluble sugar, soluble protein, proline, betaine,hydrogen peroxide and malondialdehyde contents, production rate and cell membrane permeability ofB. dasyphylla rose with increases in salt concentration and pH. There were differences between the treatmentgroups and the control (P < 0.05). The activities of superoxide dismutase, peroxidase and ascorbate peroxi-dase enzymes initially increased and then decreased, but catalase activity continued to increase. The plantheight, main root length, stem thickness, branch number, lateral root number and root, stem and leaf biomasswere significantly decreased compared with the control (P < 0.05). In regard to biomass, the proportion ofroot biomass increased, but the proportions of stem and leaf biomass decreased. The correlations between thesalt component ions and the above plant characteristics indicated complex effects of salt composition on thefunctional characteristics of B. dasyphylla. This study suggests that salt-alkaline environments inhibited thefunctional characteristics of B. dasyphylla and negatively affected several physiological responses and mor-phological plasticity.

This paper investigates the volumetric behaviors, soil -water and microstructural characteristics, and static and cyclic elastoplastic responses (including the shear strength qu, initial tangent modulus E, resilient modulus MR, and permanent strain epsilon p) of a natural and stabilized expansive clay. The clay was stabilized by a magnesium oxychloride cement (MOC) based multiphase cementitious agent, which is a novel, sustainable, and eco-friendly binder. Experimental results demonstrated that (i) the MOC-based agent effectively reduces the swelling potential, volumetric strain, and water -retention capacity of the expansive clay; (ii) The stabilization process improves the qu, E, MR of the clay by about 2-7 times and reduces its epsilon p by about 50-80% upon cyclic loading. Such improvement was especially significant under wet conditions when subgrade soils are prone to water damage. The sensitivity of the qu, E, MR, and epsilon p to moisture content fluctuation is significantly reduced (by 57-70%); (iii) the agent modifies the clay's microstructure by extensively reducing the volume of macropores while moderately reducing the volume of micropores, which are considered responsible for the increase in the clay's mechanical properties and the decrease in their moisture sensitivity; (iv) the qu-MR and E -MR relationships show unique and linear characteristics for the natural and stabilized soils. Linear empirical equations are proposed for predicting their MR at various moisture contents. Besides, a semi -empirical model is developed to describe the variation of the qu, E, MR with soil suction and moisture content for the natural and stabilized soil, which has achieved good agreement between the model predictions and experimental measurements.