Difference In Growth And Physiology Of Salix Psammophila Yanliu Yihao In Response To Different Saline-Alkaline Stress Factors

Saline-alkaline soil is widespreaded in the world.There are also a various of saline-alkalin g soil type in China.The saline-alkaline soil is the threat to food production, and it also a threat of biodiversity and ecological balance. Although there are many measures of improving the sali ng-alkaline soil, the best measure is biological measures, the effect of biological mesure is the 1 ongest, and sustainable.Nowadays, there are many studies about the salt stress on plant, but the study abou the alk ali stress on the plant is very little. But in the real environment the salt and alkali is co-exist,pre vious studies have show that salt stress is different from the alkali stress. the previous result ca n not be used in the real environment. So that strenghen the study about the alkali stress on plan and the rules of plant under the alkaili is very meaningful. Willow as an afforestation trees speci es is very common in china. But the study about the salt stress on willow is very little. So it is v ery meaningful for studying the comparative effects of salt and alkali stress on willow.The stud y In artifical simulating natural willow was studied in green house house, We set up five conce ntration (control?50?100?150?200mmol/L), Studying the height of net growth, biomass, diameter growth, chlorophyll content, the activity of antioxidant enzymes and the Osmotic adju stment substance of the willow,The result wer as below:1.The salt and alkali all can restrain the growth of Salix psammophila,Mainly in the limit height of net growth,biomass,diameter growth and chlorophyll content of Salix psammophila le af can be reduced. Comparing to the neutrual salt the net growth, biomass, diameter growth and chlorophyll content of Salix psammophila are reduced greatly under the alkali stress in the sa me concentration.2.The salt and alkali result in oxidative stress. With the increasing of the concentration of t he salt and alkali, the activity of SOD?POD?CAT also increasing, and the content of MDA i n the Salix psammophila also increasing. And the activity of enzyme changes more under alkali stress in contrast to under salt stress, In addition to slightly reduction of CAT activity in the 20 Ommol/L, contrast to the last concentration,tha activity of other two enzymies increase under n eutral salt.The activity of three enzymies decreasing after reach peak.Therefore that the alkali r esult in more oxidative stress on the Salix psammophila.And the content of MDA of Salix psa mmophila can be more under the alkali stress,and up to the summit when the concentration is 2 OOmmol/L.In comparing to the netural salt the difference is very significant.3.The salt and alkali result in osmotic stress on the Salix psammophila. As the increasing of concentraiton of salt and alkali, the leaf water content of willow will decreases,and is lowest in 200mmol/L.and The content of osmotic adjustment substances (proline, soluble sugar, solubl e protein) increaes the content of water of Salix psammophila is more lower in contrast to unde r the netural salt. When the concentration is 200mmol/L, the content of water is lowest and the difference is extreme significant. The content of proline, soluble sugar, soluble protein is lighte r when under the alkali stress.In summary the effect of salt and alkali stress on growth and physiology of Salix psammo phila is defferent. Salt stress and alkali is dfferent stress. Due to the high pH value the alkali str ess restrain willow strongly with the oxiditive stress and osomotic stress on the Salix psammop hila is more serve.