The Distribution Of Na~+ And C~- Ions In Sugar Beet Under NaCl Stress And Related Physiological Changes

Soil salinization is one of the important environmental factors that affect plant growth and development,and a global environmental problems.Two different salt tolerance varieties of sugar beet,T510 and 210 were chosen to be the objects of this study and let them growth in 3 concentration of NaCl:control check?CK?,140mmol/L?LS?,280mmol/L?HS?.Salt treatment on beet when it grown to cotyledon stage,a pair of true leaves stage,three pairs of true leaves stage.And then study on their different ion distribution.Salt stress related physiological and biochemical indexes are also be determined and analysed.The results showed that:?1?The two seedlings under salt stress decreased significantly compared with CK in plant height,leaf area,shoot dry weight and root dry weight;Sugar beet in cotyledon period is most sensitive to salt stress;210 is significantly lower than T510 in plant height,leaf area,shoot dry weight and root dry weight under salt stress.?2?The order from high to low of Na⁺and Cl^-concent in beet under salt stress is petiole>leaf>root;Excessive Na⁺and Cl^-can be placed in the old leaves by ion compartmentation of beet.Na⁺concent in apoplast and protoplasts of beet leaf is increased with the increase of salt concentration.The increase of salt concentration.Content of sodium and chlorine in epidermal cells of beet leaf under salt stress increased,and the gains especially evident in old leaves.?3?The leaf water potential and relative water content of beet decreased with increasing salt concentration,but elevated conductivity and MDA content increased.And T510 membrane systems less effect than 210 by salinity.SOD,GPX,CAT and APX activity in beet leaf increased under salt stress,and the increase of T510 is more than 210.ATP enzymes activity in leaves is significantly improved under salt stress.?4?The nitrogen and potassium content in roots,petioles and leaf of beet is significantly reduced under salt stress,but the phosphorus content increased.Indicating that salt stress effects on plant nutrient absorption.?5?The content of ABA increased under salt stress,but IAA and GA₃content decreased.ABA in T510 is lower than 210,and IAA,GA₃ content in T510 is more than 210 under salt stress.Above all,the salinity effects the physiology and metabolism of sugar beet,and sugar beet could against salt stress by ion compartmentation.The different degree of damage between the two seedlings by salt is caused by the difference of Ion compartmentation and physiological responses.