| As the pioneer tree species which is widely and entensively used for saline wasteland afforestation in northern china’s ecologically fragile regions,Elaeagnus angustifolia L.seedlings were used as the experimental material in this paper.Water control and salt control experiments were carried out by potted plants.Methods of observation,Li-6400 portable photosynthesis instrument measurement and laboratory analysis were used to observe the growth morphology and measure the height,ground diameter,biomass growth and changes of physiological and biochemical indexes of Elaeagnus angustifolia seedlings under the different degree stress of 2 kinds of salt(NaCl and Na2SO4).Reveal angustifolia under the two salt stress adaptation mechanisms of salt tolerance and size.Provide reference and guidance for the plant choice in the process of biological improvement,exploitation and utilization in different types of saline alkali soil.It is concluded that:(1)The growth of Elaeagnus angustifolia was inhibited obviously,and the distribution pattern of the biomass was changed under the 2 kinds of salt stress.The root shoot ratio increased with the stress level increased.The photosynthetic rate and chlorophyll content in leaf were lower than the control variously.(2)Under NaCl salt stress,when the concentration less than 100 nmo·L-1,the leaves were controlled by stomatal limitation,and controlled by non stomatal limitation at concentrations higher than 100 mmol·L.1.The main organic infiltrations to maintain the normal physiological structure of the cell function as regulators of malondialdehyde and proline.Under Na2SO4 salt stress,when the concentration less than 200 mmol·L-1,the leaves were controlled by stomatal limitation,and controlled by non stomatal limitation at concentrations higher than 200 mmol·L-1.MDA,soluble protein and superoxide dismutase mainly for maintaining the stable of cell function.(3)The growth threshold under NaCl and Na2SO4 stress of Elaeagnus angustifolia were 272 and 318mmol·L-1.The growth status in Na2SO4 salt soil was better than in NaCl salt soil,under the same concentration.Based on the above results,Elaeagnus angustifolia,under NaCl and Na2SO4 salt stress,owned different chlorophyll decomposition rate and organic osmotic adjustment substances,so that the plants have leaves with different health levels and the photosynthetic capacity of leaf was inhibited.All these differences between NaCl and Na2SO4 stresses ultimately reflected in the growth and a different salt tolerance. |
