Genetic Diversity Analysis And Salt Tolerance Study Of The Germplasm Resources Of Leymus Chinensis

Leymus chinensis as the gramineous grass is a herbaceous plant belonging to the genus Leymus,a typical fine grassland species in the Songnen grassland in northern my country and eastern Eurasia,fine to drought,cold,saline soils with high tolerance,also has the development potential is one of the grass,it has significant financial condition and social benefits in the development of grassland animal husbandry.Domestic and foreign studies on genetic diversity of Leymus chinensis rarely make the news and salt resistance investigation and evaluation,therefore,genetic diversity research and salt tolerance analysis of Leymus chinensis germplasm materials,preliminary screening best comprehensive properties of Leymus chinensis germplasm materials,can be used as screening of Leymus chinensis salt resistance stuff and provide important basis for breeding,in order to elucidate the physiological mechanism of Leymus chinensis alkali,and enrich Leymus chinensis germplasm repository.In this experiment,the genetic diversity of 48 Leymus chinensis germplasm materials was analyzed,and the genetic relationships were revealed preliminarily.The photosynthetic indexes of 7 Leymus chinensis materials were contrast and their photosynthetic characteristics were analyzed.The seed germination and seedling growth of 7 Leymus chinensis materials were studied under different concentrations of Na Cl and Na2CO3 salt stress.Simultaneously,the physiological characteristics 4 Leymus chinensis seedlings to salt stress was studied to explore the salt tolerance of Leymus chinensis seedlings.The main results are as follows:1.Research on genetic diversity of Leymus chinensis germplasm resources.Using 48 Leymus chinensis germplasm materials,23 pairs of SSR primers were initially screened,and 12 pairs of SSR primers with good amplification and stable polymorphism were screened,and 51 alleles were amplified,of which 41 is a polymorphic site,and the percentage of polymorphic sites is 80.39%.Shannon Information Index has extent of 0.5772～0.6923;the PIC value ranged between0.3014～0.4561,high polymorphism of genetic loci.It demonstrates that the selected primers can well reflect the genetic diversity of 48 Leymus chinensis materials.2.Study on photosynthetic characteristics of Leymus chinensis.According to the analysis of photosynthetic characteristics of 7 new Leymus chinensis strains,the new strain"LC013"had the highest chlorophyll content(1438.4mg/m~2),the net photosynthetic rate,transpiration rate,and stomatal conductance diurnal change curves all have the highest one,and each variety(line)reaches the maximum between 11:00-13:00,"LC013"strain of Leymus chinensis new net photosynthetic rate,transpiration rate,stomatal conductance peaks are higher than other strains and their values were 20.22,8.49,0.344 umol/m~2/s,followed by"LC011"new strains,Leymus chinensis seven varieties(strains),the intercellular CO2 concentration,net photosynthetic rate and stoma conductance of 7 new Leymus chinensis varieties(strains)are inconsistent,first decreasing and then increasing.3.Research on the response of Leymus chinensis seeds to salt stress.Under the stress of different concentrations of Na Cl and Na2CO3,the germination rate,germination vigor,germination index,vigor index,root length and shoot length of7 Leymus chinensis strains decreased gradually.The more the stress,the greater the adverse effect.Under low salt stress,the inhibition of seed germination is small.When the Na Cl concentration is 400 mmol/L and the Na2CO3 concentration is 150 mmol/L,"LC011","LC013","LC016"and"Nongjing 11"could all germination."LC011"and"LC013"Leymus chinensis seeds have strong salt tolerance.4.Responses of Leymus chinensis to salt stress at seedling stageThrough the analysis of the physiological indicators of two salt stresses of different concentrations of"LC011","LC013","LC016"and"Nongjing 11",it is inferred that at the initial stage of the two salt stresses,"LC011","LC013","LC016"and the"Nongjing11"super oxide active enzyme,peroxidase,catalase,and soluble sugars all rised,along with the stress cycle and salt concentration,the increase of the three enzymes and the soluble sugar content decreased,in Leymus chinensis leaf malondialdehyde,free proline content increased gradually improve adaptability to salt stress.Compared with the four groups,the decline of physiological parameters of"LC013"was lower than that of"LC011","LC016"and"Nongjing 11",indicating that"LC013"had better salt tolerance.