Genetic Diversity Analysis And Salt Tolerance Study Of The Germplasm Resources Of Amaranths Hypochondriacus L

Amaranthus hypochondriacus is one of the common forage plant used for ecological environmental construction and for livestock production in China.On account of that it has the characteristics of cold resistance,salt and alkali resistance,barren tolerance.Few reports have been done on the identification and evaluation of the salt tolerance of Amaranthus hypochondriacus at home and abroad,with a genetic diversity analysis and salt tolerance study of Amaranthus hypochondriacus germplasm materials,which thus constitutes an important basis for the selection and identification of salt-resistant materials in Amaranthus hypochondriacus.In this experiment,the genetic diversity of 18 germplasm materials of Amaranthus hypochondriacus were studied.The genetic diversity was revealed.The photosynthetic characteristics of new strains of Amaranthus hypokondriacus were investigated.The germination,plant growth and physiological properties of the seeds of 4 Amaranthus hypokondriacus strains were investigated in response to salt stress and the salt isolation of cereals of amaranth plants was investigated.The main findings are as follows:1.Genetic diversity of Amaranthus hypochondriacus germplasm resources.Using 18 germplasm materials of Amaranthus hypochondriacus to screen through30 pairs of SSR primers,and eventually 21 SSR primers with clear bands,good amplification and stable polymorphism,90 alleles were amplified,81 of which were polymorphic;the percentage of polymorphic loci was 90.00%;the Shannon information index change range was 0.2958 to 0.6917;the PIC value ranged between 0.1463 and0.3742,and the selected SSR marker has a moderate polymorphism level.It showed that the selected primers could well reflect the genetic diversity of 18 Amaranthus hypochondriacus.2.Study on Photosynthetic Characteristics of new strains of Amaranthus hypochondriacusSome photosynthetic index of leaves which including Net photosynthetic speed,perspiration rate,stoma conductivity,intercellular CO2 concentration and chlorophyll content were measured and analysed of 10 Amaranthus hypochondriacus strains.The net photosynthetic rate,transpiration rate and stomatal conductance degree of 10 new Amaranthus hypochondriacus varietiesare all bimodal.The photosynthetic rate,transpiration rate and stomatal conductance peak values of LX014 new Amaranthus hypochondriacus strains were the highest,which were 26.12μmol/m²/s,6.78mmol/m²/s and 0.258μmol/m²/s,respectively,the chlorophyll content of LX014new strain was also the highest at 1203mg/m²,followed by LX012 new strain of Amaranthus hypochondriacus.The intercellular CO₂concentration of 10 new Amaranthus hypochondriacus varieties was negatively correlated with net photosynthetic,transpiration rate,and stomatal conductance,and all showed a"W"shaped curve.The photosynthetic rate,transpiration rate,stomata conductance and chlorophyll content of LX006 new Amaranthus hypochondriacus strains were the lowest.It was showed that LX014 and LX012 were superior to other Amaranthus hypochondriacus in terms of photosynthetic characteristics.It has the potential to breed new species of Amaranthus hypochondriacus.3.Study on the response of Amaranthus hypochondriacus seed germination to salt stressWith the different consistences of Na Cl,the germination rate,germination potential,germination index,activity index and seedling growth of 4 strains of Amaranthus hypochondriacus decreased with the increase of concentration,while the relative salt damage rate increased with the increase of concentration.Low concentration of salt had no significant effect on seed germination.With the 200 mmol/L Na Cl,all the Amaranthus hypochondriacus seed germinated.The LX014 and LX012had better salt tolerance.4.Study on physiological characteristics of Amaranthus hypochondriacus seedlings in response to salt stressUnder the stress of different concentrations of Na Cl,the average seedling length of the 4 strains of Amaranthus hypochondriacus seedlings was inhibited.The low concentration of salt on seedling growth germination was not significant.Under200mmol/L Na Cl stress,with the root length was significantly inhibited,so the length of the seedlings was significantly shorter than the control group.The seedling growth of LX014 in the 4 strains of Amaranthus hypochondriacus was better than the other three,indicating that LX014 had better salt tolerance in seedling stage.5.Study on the response of Amaranthus hypochondriacus physiological characteristics of seedlings to salt stressThrough the analysis of physiological characteristics of the seedlings of 4 new strains of Amaranthus hypochondriacus,under different concentrations of Na Cl and Na₂CO₃stress,it was concluded that with the increase of salt concentration and the extension of stress time,the content of malondialdehyde and free proline in leaves of LX012 and LX014 increased gradually,and the activity of superoxide activity enzyme,peroxidase,hydrogen peroxide enzyme and soluble sugar content increased first and then decreased;The contents of malondialdehyde and free proline in the leaves of LX006 and LX019 also gradually accumulate,but the content is low,and its penetration ability is poor.Other physiological indicators also show that the salt tolerance of LX006and LX019 is worse than that of LX012 and LX014.