Study On Evaluation Of Salt Tolerance In Zoysiagrass(Zoysia Willd.) And Its Ion Regulating Mechanism

Zoysia Willd.is a perennial herbaceous plant of the genus Chloridoideae,which has about 11 species and some variants.There are 5 species,2 variants and 1 variants in China.Zoysia macrostachya,Zoysia japonica and Zoysia matrella 3 species are classified as halophytes.Zoysia plant has a very strong resistance,drought tolerance,salt tolerance,less pests and diseases,abrasion resistance,strong cold resistance,the world recognized it as a good warm season turfgrass,can be widely used in viewing Lawns,open lawns,sports lawns and soiled lawns.Therefore,Zoysia is one of the alternative grasses of saline-alkali landscaping,which has a very strong superiority and it is of great significance to study the salt tolerance of zoysiagrass.In this study,the salt tolerance of 206 zoysiagrass was studied by hydroponic method,and the mechanism of salt tolerance control was studied.On the one hand,it laid the foundation for the discovery of salt-related gene resources of Zoysia,On the other hand will also be high quality salt tolerance of new varieties of Zoysia and its cultivation and control technology research and development to provide a scientific basis for the final service in China's saline soil and ecological construction.The main conclusions of this paper are as follows:1?Evaluation of salt tolerance in zoysiagrassThe leaf firing percentage,relative dry weights of shoot clipping,relative water concentrations,relative verdure dry weight,relative root dry weight were used as indicators,and the salt tolerance of the tested materials was evaluated.The results showed that the leaves of the plant were withered and the whole plant was withered,the water concentrations of the leaves was significantly lower than that of the control,and the growth of most plants was inhibited,and the dry weights of shoot clipping was significantly decreased.The verdure dry weight and root dry weight were different after salt treatment.The salt concentrations of the leaves was significantly lower than that of the control.In addition,according to the results of cluster analysis,the 206 zoysiagrass can be divided into five salt-tolerant salts at the Euclidean distance of 4.5,Extremely salt tolerant type(44),salt tolerant type(62),intermediate type(42),salt sensitive type(26)and extremely salt sensitive type(32),the response to salt stress of types are different.2?Study on regulatory mechanism of salt tolerance in zoysiagrass(1)Study on the change of ion concentrations of zoysiagrass under salt stressThe results showed that the concentrations of Na+ and K+ in the leaves and roots of the leaves were significantly higher than those of the control.Compared with the control,the concentrations of the Na+ in the leaves and roots of zoysiagrass were significantly increased,are 3.5 to 15 times and 3.2 to 28.4 times of the control.K+ concentrations decreased,they are 23.5%-88.3%and34.3%-96.9%of the control.After salt treatment,The variation of Na+ concentrations in the roots of different materials under salt stress was the smallest,while the coefficient of variation of Na+ content in leaves was the largest,but the coefficient of variation of K+ in roots and leaves were not much difference,which indicated that there was significant difference in the ability of transporting Na+ between different materials.The more K+ absorbed by roots,the greater the K/Na+ of roots and leaves,the greater the transport coefficient,the stronger the salt tolerance.(2)Determination of salt-secreting ability of Zoysia genus under salt stressThe results showed that compared with the control,the Na+ and K+ were analyzed in the leaves of the experiment.The results showed that the Na+ secretion concentrations of different materials was 5.28 mmol/Kg of the control,and the secretion of Na+ was significantly increased after salt treatment,with an average of 156.71 mmol/Kg,the different materials were 5.9?291.7 times of the control.In addition,The average of K+secretion concentrations was 4.96 mmol/Kg of the control,and the K+ secretion concentrations of the vast majority of materials was also increased after salt treatment,the average value was 18.46 mmol/kg,which was 1.01?18.74 times of that of the control.The greater the secretion of Na+ under salt stress,the stronger the salt tolerance.The Na+,K+secretion concentrations both increased under salt stress,indicating that Na+-K+ co-transport is also a characteristic of zoysiagrass.(3)The mechanism of ion regulation of salt tolerance of ZoysiaThe correlation between salt tolerance,salt-secreting ability and K+,Na+concentrations of leaves and roots of Zoysiagrass under salt stress was analyzed comprehensively.The results showed that the K+/Na+,the Na+ secretion,the higher K+/Na+in leaves and roots were higher,and the Na+ concentrations,leaf K+ concentrations,leaf Na+ The higher the concentrations,the higher the salt tolerance,the higher the K+/Na+ and the higher salt tolerance,the stronger the Na+ secretion,the stronger the salt tolerance.The higher K+ concentrations in the roots and the higher K+/Na+ in the roots and leaves,and the higher Na+ secretion of the leaves were the mechanism of salt tolerance control of Zoysia.In addition,Na+,K+ ion concentrations and Na+ and K+ secretion concentrations were significantly positively correlated,indicating that there was a Na+-K+co-transport mechanism in zoysiagrass.In short,Zoysiagrass absorb more K+ through roots,maintain high root and leaf K+/Na+,leaves secret more Na+,and Na+-K+co-transport are the mechanisms for salt-tolerant control.