Appraisal Of Alkali Tolerance Idioplasm Of Maize At Seedling Stage And Analysis Of Heredity Of Partial Characters Under Salt Stress

Salt soil is a broad distribution soil type in the world.At present salinization of the soil has become one of the increasingly serious environmental problems which is affected by global climate changes and population growth.Salt soil is mainly divided into two types that one is salt soil which mainly include neutral salt such as NaCl and Na₂SO₄ etc. and the other is alkaline soil which mainly include alkaline salt such as Na₂CO₃ and NaHCO₃ etc. in our country.Alkaline salt dose more harm to crops than neutral salt.This because the pH of alkaline salt is very heigh and utilization of mineral is reduced besides infiltration menace and ion harm as neutral salt.And heigh pH is the most harmful factor,the second one is ion harm,and the last one is infiltration menace in those harms.Maize is an important crop,industrial raw material and medical raw material which is middle sensitive to salt.It,s comparative output is very heigh but it,s salt tolerance is very poor.In this study,the changes of morphology and growth under different concentrations of Na₂CO₃ stress at germination stage and seedling stage were measured in order to appraise alkali tolerance of maize.Further to study the appraised indexes and methods of alkali tolerance in seedling stage and appraise the alkali tolerance of different inbred lines of maize.Two precocious inbred lines were selected to study the changes of morphology,growth and physiological-biochemical under different concentrations of Na₂CO₃ stress at seedling stage,and the mechanism of salt tolerance of maize was discussed.Furthermore,heredity effect of partial characters of maize under salt stress were analysed.The maize with alkali treatment at germination stage performed that the germination force and germination rate were affected lightly while the growth inhibition of the roots and buds were obvious.When concentration of Na₂CO₃ was higher than 25mmol/L,the alkalinity hazard of maize also achieved the highest degree,performed that the buds and roots stopped growing after germinated,and the seeds which stopped growing couldn,t renew growing after they were shifted to distilled water.The height,fresh weight,dry weight and water content of seedlings were decreasing significantly with the increasing of concentrations of Na₂CO₃,different concentrations of Na₂CO₃ and different inbred lines were different.But that could cause the death of seedlings when the concentration of alkali was higher than 25mmol/L.The appearance,height,fresh weight,dry weight and water content under the concentration of 25mmol/L Na₂CO₃ could be the appraised indexes of alkali tolerance at the seedling stage.According to the seedling appearance,the height of plants, the fresh weight of seedlings, the dry weight of seedlings and the water content of seedlings under the concentration of 25mmol/L Na₂CO₃ stress,in the 101 inbred lines,the ratio of high alkali tolerance inbred lines was 16.83～17.82%,the ratio of alkali tolerance inbred lines was 61.39～68.32%,the ratio of moderate alkali tolerance inbred lines was 9.90～15.84%,the ratio of alkali sensitive inbred lines was 2.97～4.95% and the ratio of highly sensitive inbred lines was 0.99～1.98%.The study of two precocious inbred lines under different concentrations of Na₂CO₃ stress at seedling stage showed that the height,fresh weight,dry weight,water content,chlorophyll content and root vitality of the inbred lines were all decreasing with the increasing of concentrations of Na₂CO₃,the relative conductivity and proline content of the inbred lines were increasing with the increasing of concentrations of Na₂CO₃,the SOD activity of the two inbred lines both increasing at first and then decreasing with the increasing of concentrations of Na₂CO₃.The analysis of heredity effect of partial characters of maize under salt stress showed that under the salt-stress,different genotypes were really different,the SCA of plant height,dry weight of maize at seedling stage and grain weight per plant,ear length,ear thickness,weght of hundred grains,produced seed ratio of ear of maize were extremely striking while the GCA weren't striking except ear thickness and produced seed ratio were striking;Non-additive variance of indexes were bigger than additive variance,and narrow heredity were all small.So the characters that were relative to salt tolerance were selected in the early age was inadvisable when selected inbred lines which were salt tolerance,the special combining ability was important when selected hybrid which were salt tolerance.