Select Of Different Wheat Varieties And The Mechanism Of Physiological And Biochemical Response To Saline-Alkaline Tolerance

To increase and stablize the yield of crops in low middle yield field with abiotic stress limitation,in this study,aiming at restrictive factors for the growth of crops in soda saline-alkali soil regions and secondary salinized farmland,30 main cultivated wheat varieties in Northeast Area were chose,and NaHCO₃ of 5 concentrations from 50 mmol·L^-1 to 250 mmol·L^-1,to screen saline-alkaline tolerance of kidney bean at seedling stage.Saline-alkaline tolerant variety Longmai36 and saline-alkaline sensitive variety Jiusan08-7127 were used as materials.Germination characteristics of wheat and salt-tolerant mechanism of seedlings were compared and studied.Main results were as follows:1.Screening of salt tolerance of different varieties of wheat during germination and seedling stageSeed germination rate,germination potential,germination index,vigor index,coleoptile length,root length and seedling growth showed obvious difference with different concentrations of salt and alkali in different varieties of wheat,along with the increases of salt and alkali concentration the growth index showed a trend of gradual decline,different concentrations of NaHCO₃ solution respectively in wheat germination stage and seedling stage under saline alkali stress,obtain the suitable stress concentration was 150mmol·L^-1,Through the fuzzy mathematics method of membership function,principal component analysis（PCA）and clustering analysis（CA）divide the 30 varieties of wheat into three groups,according to the performance of different varieties wheat variety in the test,select Longmai 36（L36）and Jiusan 08-7127（08-7127）as the material for the further mechanism research.2.Effects of saline alkali stress on seed germination of different salt alkali tolerant wheatThe different varieties wheat seeds treated with low concentration of NaCl and NaHCO₃,the germination and growth all get promote.While the high-level(≥150mmol·L^-1)salt and alkal concentration is toxic to the wheat seedlings and inhibit their growth.The effects of salt and alkal stress on theα-amylase activity and hepatocytes membrane steady of wheat seed will be restrained,dry matter accumulation of the seedlings decreased dramatically with the increase of salt and alkal stress intensity.with the increasing of treatment concentration the inhibition enhanced gradually.Two varieties showed significant differences,Compare 08-7127 and L36,growth and change more obvious with the increasing of NaCl and NaHCO₃ concentration,the growth changes of 08-7127 are more significant than L36 at the same treatment concentraions.3.Effects of saline alkali stress on growth and physiological characteristics of wheat seedlings with different different salt alkali tolerant varietiesThe different concentrations of salt and alkal treatment have significant physiological characters impact on wheat seedlings.When the Na⁺concent of treatment is between 25 and 50mmol·L^-1,the growth and the accumulation of photosynthetic product are increased in different varieties wheat seedlings,the protective enzyme activity of leaf is also increased,and promote the growth of wheat seedlings.When the Na⁺concent of treatment is between 150 and 200mmol·L^-1,the growth and the accumulation of photosynthetic product are restrained in different varieties wheat seedlings,the protective enzyme activity of leaf is also decreased,and restrain the growth of wheat seedlings.With the increase of saline alkali stress,the osmotic adjustment substances in plant leaves were accumulated,and the ion balance was destroyed.The destructive effect of NaHCO₃ treatment was more obvious than that of NaCl treatment,and more sensitive to salt and alkali stress.the change of the indicators in 08-7127 is more significant than L36,08-7127 is more sensitive to salt and alkali stress.