Effects Of NaCl Stress On Seed Germination And Seedling Growth Of Chenopodium Quinoa Willd

Quinoa has a very high nutritional value,with a protein content of about 18-23%,which is twice as high as that in rice,much higher than barley,and almost as the complete protein of animals.Quinoa has high application potential in industry,agriculture and ornamental.At present,soil salinization has become the main ecological problem in our country and even around the world.Quinoa has high salt tolerance,which can be used for the potential plants in saline-alkali land.In the present study,the quinoa cultivar cv Zk7 was used as plant material,the seed germination capacity and seedlings growth under NaCl treatments and rehydration treatment were adopted.We are trying to understand the NaCl stress threshold for seed germination and normal growth of seedlings of quinoa.Herein,we explored the recover effects of rehydration on quinoa after salt stress treatment.The aim of this study is to provide a basis for the search of methods to alleviate salt stress on quinoa.The main conclusions of this paper are as follows:（1）With the increase of NaCl concentration,the germination rate of quinoa seeds increased first and then decreased.Low concentration of NaCl(50,100 mmol·L^-1)can promote the germination of quinoa seeds,and improve the germination percentage;high concentration of NaCl significantly reduced the germination rate of the seeds.under 300 and400mmol·L^-1NaCl,the germination rate was 13.7%and 16.8%of the control respectively.We concluded the NaCl threshold for quinoa seeds germination was 200 mmol·L^-1NaCl.Rehydration treatment can effectively promoted the germination of seeds in the high concentration NaCl treatment group,and the germination rate in the low salinity treatment group remained the same after rehydration treatment.（2）With the increase of NaCl concentration,the chlorophyll content of quinoa seedlings decreased gradually.The content of chlorophyll a and b in each treatment group were higher than those in the single NaCl treatment group.With the increase of NaCl concentration,the stomatal area and the total number of stomata decreased gradually,and the stomatal area and the number of stomata increased significantly after rehydration.（3）More proteins with low-molecular weight were induced in dehydration group compared with single NaCl treatment group.With the increase of NaCl concentration,the soluble protein content of quinoa seedlings increased gradually.After rehydration,the content of soluble protein was lower than that of NaCl alone.The activity of antioxidant enzymes in leaves increased first and then decreased with the increase of NaCl concentration.After rehydration,the activities of antioxidant enzymes in each treatment group increased than those in NaCl treatment alone,and the increment of the antioxidant enzymes activities in the high NaCl concentration treatment group were higher than those in the low salt treatment group.（4）At the early seedling stage,low concentration NaCl promoted the elongation of the quinoa root system,while 250-400 mmol·L^-1NaCl inhibited the root growth.With the increase of NaCl concentration,the degree of membrane lipid peroxidation increased,and the activities of antioxidant enzymes increased first and then decreased.Rehydration significantly increased the activities of SOD and POD,effectively alleviated the oxidative damage of free radicals to root cells,promoted root elongation and accelerated root growth.（5）A low concentration of NaCl promoted the growth of quinoa seedlings,and a higher concentration with more than 200mmol·L^-1NaCl presented inhibition effects.After rehydration,the leaf area of each treatment group increased gradually,the plant height and stem diameter also increased rapidly,the biomass accumulation promoted accordingly.This is to say,rehydration can effectively relieve the inhibition of NaCl stress on quinoa seedling growth.（6）Quinoa has high nutrition value,salt tolerance and unique ornamental value,and therefore shows unique ecological functions in the landscape building in saline alkali land.Quinoa can be used to enrich the landscape of saline alkali land and promote the new industrial development of Jing Le county.