Studies Of The Difference Of Salt Resistance Of Ulmus Pumila

We were proceeded the experiment through salt content in pot culture on Ulmus pumila of different provenances. Five provenances of one-year seedlings were proceeded seven levels of salt treatment CK, A (2‰), B (4‰), C (6‰), D (8‰), E (10‰) and F (12‰). The regular diameter, shoot growth and leaf area growth were periodically measured. After a period of salt treatment, the physiological and biochemical indexs reflecting salt resistence were measured, including proline, soluble sugar, chlorophyll, conductivity, the survival rate ,photosynthesis and other physiological and biochemical indexs.The main results were as follows:1 The results of pot culture show that five Ulmus pumila provenance have different salt-resistant ability, the ability of its salt tolerance was in order of Haixing, Yanshan provenance> Huanghua 1, Huanghua 2 provenance > Baoding provenance.2 Salt stress inhibit the normal growth of plants so that the lower dry matter accumulation. With the salt stress strengthened, and relative growth of diameter, the relative growth of new shoots and relative leaf area showed lower growth trend.3 With the increasing concentration of salt stress, the proline and soluble sugar content of five sources Ulmus pumila leaves was rising, the starch content was falling. Ulmus pumila can control starch content in the leaves to regulate soluble sugar content, to maintain the balance of infiltration, showing a salt tolerance.4 With the salt stress strengthened, the permeability of the membrane showed the aggrandized trend and the difference between the provenances of Ulmus pumila significant. Ulmus pumila (Huanghua, Haixing, Yanshan) of Coastal provenance more stability than those in non-coastal provenance (Baoding) for the salt stress response, because its leaves the cell membrane permeability of different salt stress changes slowly.5 With the salt stress strengthened, the net photosynthetic rate, transpiration rate, stomatal conductance and intercellular carbon dioxide concentrations of Ulmus pumila was decline. There are certain differences between provenance of Ulmus pumila, and the degree of decline in the coastal provenance relatively Small.6 With the salt stress strengthened, the Na~+ in leaves of Ulmus pumila was rising, the K~+ in leaves of Ulmus pumila was generally higher and when the salt level over the 2‰then slow decline. The K~+ content in the leaves Under salt stress has always maintained a high level than antitheses, the leaves gathered in the high concentration of K~+ for the organization to provide not only a lot of nutrients, to make up for active metabolism caused by nutritional deficiency, but also its As osmosis to meet the conditions of salt. With the salt stress strengthened, the Na~+/K~+ in leaves of Ulmus pumila under Salt stress was rising, compared with antitheses, the Na~+/K~+ in leaves of Ulmus pumila increased significantly. 7 Ulmus pumila showed a strong salt-tolerant, but among them there is still a significant difference. The lower salt tolerance, like the obvious symptoms of salt injury of Baoding Ulmus pumila provenance, the more obvious indicators of change; The higher salt tolerance, like the Yanshan and Haixing Ulmus pumila provenance ,the indicators are more stable. The ability of its salt tolerance was in order of Haixing, Yanshan provenance> Huanghua 1, Huanghua 2 provenance > Baoding provenance. Ulmus pumila of Haixing, Yanshan provenance is more suited to high salinity stress growth, more be adapt to coastal saline areas ecological restoration.