Effect Of Mixed Salinity Stress On Growth And Ion Absorption Of Cyperus Esculentus L.

Soil salinization has become the biggest obstacle to agricultural production,which has a greater impact on the yield and quality of crops.At present,as a saline-tolerant crop with high economic and ecological benefits,oil-sand beans have attracted more and more attention in recent years.In this paper,the mixed saline-alkali stress test was carried out by artificially using Na Cl,Na₂SO₄,Na HCO₃,Na₂CO₃（12:9:8:1）four salts,Salts of 3 g?kg^-1,4.5 g?kg^-1,5 g?kg^-1,7.5 g?kg^-1,and 10 g kg^-1were added to each treated farmland soil,by determining the growth index,osmotic regulatory substance,photosynthetic parameters,The response of oil salvia to saline stress under different concentrations was studied,and its salt tolerance was understood.The main conclusions are as follows:（1）Effects of different saline alkali stress on growth indexes of C.esculentus.With the increase of saline alkali stress,the plant height,number of tillers,number of leaves and fresh and dry weight of C.esculentus showed a downward trend.Only when the saline alkali concentration was less than 3g·kg^-1,it promoted the root system in 0-15cm soil layer,indicating that saline alkali stress significantly inhibited the growth of aboveground parts of C.esculentus,but 3g·kg^-1saline alkali concentration could stimulate the root system growth of C.esculentus in 0-15cm soil layer.（2）The effects of different saline-alkali stress on the physiological indexes of C.esculentus.With the increase of the degree of saline-alkali stress,the contents of MDA and pro in the leaves of C.esculentus showed an upward trend;while the contents of soluble sugar and soluble protein,as well as the activities of POD and SOD,generally showed a trend of first increasing and then decreasing.Among them,the soluble sugar content reached the maximum under the T4 treatment at the tillering stage and the bean-bearing stage,and reached the maximum under the T2 treatment at the mature stage.The content of soluble sugar and soluble protein,while increasing the activity of POD and SOD in leaves to resist the damage caused by saline-alkali stress.（3）Effects of different salinity stress on photosynthetic indexes of C.esculentus.With the increase of salinity stress,the chlorophyll content increased in the tillering stage,while the bean-bearing stage and the ripening stage showed the decline and decline trend,respectively.Pn also showed a trend of rising first and then decreasing in both the tillering and bean-bearing stages,both reaching the maximum under T3treatment,and a decreasing trend in the ripening stage.Gs and Tr showed a downward trend at the tillering stage,but also decreased in both bean-bearing and ripening stages.It shows that under mild or short-term salinity stress,it can increase its chlorophyll content,Fo,q N,Y（NPQ）and Y（NO）show increasing trend,Fv/Fm,ΦPSⅡand q P show decreasing trend,Fm first rise and decrease,indicating that it can initiate its protection mechanism and lose excessive light energy to protect the chloroplast structure of plants through fluorescence and heat dissipation.（4）The effect of different salinity stress on ion absorption and transport in C.esculentus.Na⁺accumulated in roots under saline stress was greater than leaves except for T5 treatment,and Na⁺accumulated under mature treatment.K⁺content was manifested as leaves larger than roots in all periods.Ca²⁺,with the increase of salinity stress,the leaf content gradually decreased,and the roots showed the trend of rising first and then falling,and the root content was greater than the leaf content,while the Mg²⁺content showed an upward trend in the leaves,and the roots also roughly showed the trend of rising first and then decreasing.It shows that Na⁺in roots under salinity stress,and Na⁺in leaves during maturity.Its inorganic osmotic regulatory materials are mainly Ca²⁺and Mg²⁺in roots,K⁺and Mg²⁺in tillering stage,and Na⁺ions in tillering stage.（5）The effects of mixed saline-alkali stress on microbial traits in different soil layers of C.esculentus.With the increase of salinity,the relative abundance of Proteobacteria,Gemmatimonadetes and Paterscibacteria showed an increase,while the relative abundance of Acidobacteria and Verrucomicrobia decreased gradually,while the variation of Shannon and Chao1 diversity index in the bacterial community structure showed a law of first rising and then decreasing.To sum up,the C.escuulentus can grow well in the saline-alkali soil equal to less than 5g·kg^-1,and the yield and various growth indicators decrease significantly in the soil higher than 7.5g·kg^-1.