Salt Tolerance Evaluation Of Six Cultivated Species In Datong Basin And Study On Salt Tolerance Of Tamarix Austromongolica Nakai

Soil salinization is serious in Datong Basin.In order to carry out a reasonable and effective ecological restoration and utilization in the region, this article first cultivated six native tree species of Tamarix chinensis Lour.,Lycium chinense Miller var., Pinus sylvestris Linn. var. mongolica Litv. Juniperus rigida Sieb. et Zucc.,Ulmus pumila L., Populus alba L. var. pyramidalis Bge. seedlings in the nursery, and irrigation treatment of NaCl with various levels of salt stress(0%,1%,3%,5%), researched the effects of salt stress on the morphological characteristics, photosynthetic rate, stomatal resistance, transpiration rate, intercellular CO2content and membrane permeability and other indexs, And the result of comprehensive evaluation of salt tolerance is:from high to low is Tamarix chinensis Lour.,Lycium chinense Miller var., Pinus sylvestris Linn. var. mongolica Litv., Juniperus rigida Sieb. et Zucc.Ulmus pumila L., Populus alba L. var.pyramidalis Bge. After the first stage results, To understand the responses of Tamarix austromongolica Nakai to various levels of salt stress (0%,0.5%,1.0%,2.0%,4.0%) and discuss its salt tolerance, this paper conducted a study with pot experiments. NaCl at low concentration of0.5%has tiny effect on each physiological index of the plants. Upon treatment of NaCl at high concentrations of1.0%,2.0%and4.0%, the plants can quickly respond at stoma adjustment, protective enzyme system and osmotic regulation substances. The plants can maintain comparatively regular growth during the early treatment period (first8days). With time passing and the increase of NaCl concentration, obvious effects on plants’growth show up. On the8th day, relative conductivity of plants treated with NaCl concentration of4.0%obviously rises to4times of CK and MDA content has direct correlativity with relative conductivity. Praline content of Tamarix austromongolica Nakai under salt stress gradually rises, while soluble protein content increases in early treatment period and then gradually decreases. Activities of3protective enzymes all increase first and then decrease under salt stress. Activities of SOD and CAT reach the peak on the14th day, while the activity of POD reaches the peak on the20th day. Chlorophyll content in leaves, optimal photochemical efficiency of photosystem Ⅱ and Pn gradually decrease and have correlativity with each other, the leaves secrete salt gradually incr-eased up to1.624mg/g.. After salt-leaching, all the indices of plants treated with NaCl concentration of1%and2%can be recovered, while the indices of plants treated with NaCl concentration of4.0%can barely recover, but from their own form of growth, osmotic adjustment, antioxidant enzyme regulation of Tamarix austromongolica Nakai, have shown a good salt-tolerant capabilities, able to grow in the higher salt concentration in soil.