Effects Of Saline-alkali Stress On Seed Germination And Seedling Growth

Salina is abroad in the world these years,especially in drought and semiarid aera.The problem is a restrict factor in agricultural irrigation of the world.The study of the durable to saline-alkali stress of the plant is an important effect to improve the seed germination.High pH and high concentration of Na⁺ are two factors to saline stress.In order to improve salina, three kinds of halophytic seeds were tested,and the seed germination,root length,shoot length,chlorophyll contents,proline contents,and ions in plant were measured.Then the data was analyzed by STATISTICA 6.0 software.The experiment was divided into two parts.The first part was the effect of saline-alkali stress on seed germination.The seeds of Achnatherum splendens,Sophora alopecuroides and Medicagv sativa were selected and placed in NaCl and Na₂CO₃ pollution.Then the germination and growth indexes were observed.For every 24 hours the numbers of the germination seeds were noted,root length and shoot length were tested,chlorophyll contents, proline contents,and ions were measured using standard means.So it could conclude the effect of saline and alkali stress on seed germination and seedling growth.The experiment showed,saline-alkali stress restricted seed germination rate,root length and shoot length.With the increase of NaCl and Na₂CO₃ concentration,the restrained degree was increased obviously.The content of Na⁺ was higher than CI^-,the ions in root was higher than shoot.With the increase of NaCl and Na₂CO₃ concentration the chlorophyll contents were decreased,proline contents were increased.The second part of the experiment was the alleviatory effect of CaCl₂ on seed germination at the NaCl stress.The seeds of Achnatherum splendens,Sophora alopecuroides and Medicagv sativa were treated with these solutions and the effect of saline stress on seeds germination rate,root length and shoot length were studied in this paper.The alleviatory effects of Ca²⁺ on saline stress were also studied.The content of Na⁺ and Ca²⁺ in the root and shoot of these plant were measured,the aim was to explain the correlation of ion content between plant treatment solutions.The result showed that seed germination and seedling growth indexes were lowered with the increase of NaCl concentration,the restrained degree was increased obviously.All the indexes were restrained mostly at the high concentration of NaCl respectively of Achnatherum splendens,Sophora alopecuroides and Medicagv sativa.The paper also found that adding Ca²⁺ to NaCl treatment could alleviate saline stress.Na⁺ and Ca²⁺ content in shoot and root of these plants were measured by ICP,the result showed that Na⁺ content increased with the salt content of treatment solutions,while Ca²⁺ content decreased.In general,the content of ions was in the order:Na⁺＞Ca²⁺,while ions content in root was higher that in shoot.