Effects Of Coastal Saline Soil Stress On Growth And Physiological Indexes Of 6 Functional Plants

In recent years,with the rapid urbanization process in coastal areas,the transformation and upgrading of agricultural industry and the improvement of ecological environment have become the urgent needs of social development in this area;functional plants or their products can be eaten or taken orally,which have a variety of vitamins,amino acids,minerals and other functional components,with great edible,medicinal value and economic benefits.The gradient coastal saline soil identification method was used to study the growth and physiological indexes of six functional plants(Taraxacum mongolicum,Cassia tora,Sophora flavescens,Glycyrrhiza uralensis and Althaea officinalis L.)under different salt treatments(0.1%(CK),0.2%,0.3%,0.4%,0.5%,0.6%,0.7%,0.8% and 0.9%).The salt tolerance of different plants was determined,which provided theoretical basis for the selection of functional plants and the suitable planting in coastal saline-alkali land.The results showed that:With the increase of soil salinity,the growth of six functional plants was significantly inhibited.Low-salinity soil(0.2%-0.3%)could promote the growth of plants in the early stage of salt stress.The measured values of plant height,leaf number and biomass increased,but with the time of salt stress,all functional plants were subject to different processes.Salinity damage.At 45 days,the plants of Stevia rebaudiana died when the salt content was more than 0.6%;Sophora flavescens all,died when the salt content was more than 0.7%;Taraxacum mongolicum survived less than 15% under 0.9% salt stress.At 60 d,there were more deaths from Stevia rebaudiana,Taraxacum mongolicum and Sophora flavescens.There was no death of Althaea officinalis L.,Cassia tora and Glycyrrhiza uralensis in the determination time,but with the increase of salt content,the height,stem diameter and biomass of the above three plants decreased,which were all more than 50% lower than CK(0.1%).The physiological indexes of all functional plants increased with the increase of soil salinity.The leaf membrane permeability and Pro content of all functional plants increased significantly with the increase of salt content.;the contents of chlorophyll a,b and soluble protein in the leaves of each functional plant showed different changing trends;the contents of MDA in leaves of Taraxacum mongolicum,Cassia tora and Althaea officinalis L.increased first and then decreased with the increase of salt content,the MDA content of Sophora flavescens and Stevia rebaudiana is increasing,while the MDA content of Glycyrrhiza uralensis is decreasing.Through correlation analysis,it was found that the physiological indexes of functional plants and soil salinity showed a generally consistent correlation.The plasma membrane permeability and proline content were positively correlated with salt content,and the correlation coefficient was greater than 0.910.According to the membership function of fuzzy mathematics,the salt tolerance of six functional plants were analyzed and calculated: Cassia tora > Glycyrrhiza uralensis > Sophora flavescens > Althaea officinalis L.> Taraxacum mongolicum > Stevia rebaudiana.