The Cold Tolerance And Salt Tolerance Of Different Strain Of Dense Branches Tamarix

In order to evaluate the difference in cold resistance between different types of dense-branches Tamarix,at-16°C,-24°C,-32°C,-40°C,-48°C,-56°C,-64°C,-72°C,these 8 cryogenic gradients,using randomized block experiment design,with Chinese tamarisk as a control,the freezing damage index,electrolyte leakage,soluble protein,soluble sugar and proline content of 11 species of tamarisk were determined;In order to evaluate the difference in salt tolerance between different types of dense-branches Tamarix,in the seven salt pools with total salt content of 0%,0.4%,0.6%,0.8%,1.0%,1.2%,1.4%,a random block hardwood cutting experiment was conducted to determine the salt-tolerance surface value,growth indicators,biomass,photosynthetic pigments,root-shoot ratio,and foliar salinity amount of 6 types of dense-branches Tamarix.According to the measured index,the membership function method was used to evaluate the cold resistance and salt tolerance of the tested strains.In terms of cold resistance,the electrolyte exudation rate,the freeze injury index,and the organic osmotic regulator like soluble protein,soluble sugar,and proline content were significantly different among the 12 tested strains(with contrast).Electrolyte seepage rate and freeze damage index were negatively correlated with cold resistance.The semi-lethal temperature(LT50)range of each strain obtained by the conductance method and Logistic equation was-31.07°C to-43.22°C.In terms of organic osmotic regulator: The content of protein increased with the decrease of temperature.The content of soluble sugar increased first and then decreased with the decrease of temperature,and then became stable.Proline content,with the decrease of temperature,it basically showed a tendency of increasing first and then stabilizing.They are positively related to cold resistance.Using the membership function method to comprehensively evaluate the cold resistance of these 12 tested strains(including controls),The rank of dense-branches Tamarixs from strong to weak is:D4>D3Z>4-1>D3X>0-1>D1>Jinwuzhuang>D7>Chinese tamarisk>0-2>0-3>D6.In terms of salt tolerance,the salt-tolerance surface values,growth indicators,biomass,photosynthetic pigments,root-shoot ratio,and foliar salinity amount were significantly different among the 6 tested strains.The root-shoot ratio and the foliar salinity amount increased with increasing salt concentration,the remaining indicators decreased with increasing salt concentration.Among them,the decline in root biomass was lower than the decline in leaf and stem biomass.The photosynthetic pigments of each types will increase first and then decrease with increasing salt stress.Using the membership function method to comprehensively evaluate the salt tolerance of the six tested strains,from strong to weak are: · 6> M4-5> M4-3> 4-1>M4-2> short 2.