| Wheat is major food crop in china and plant crop in soil of saline and alkali. By means of mode of banding together inside job with potted test, the tolerance to salt stress of four types wheat, was investigated in the present study by the numbers. The system of antioxidant enzymes, the accumulation of ion, osmotica and hormone in wheat under salt stress were investigated in this experiment and linked potted test.The aim is to better understand the character of physiological and biochemical response to salt stress in germination stage of wheat. The main results were summarized as follows: 1 indexes of seed germination in wheatWith the increasing of NaCl concentration, germinating energy, germination percent, height of seedling and length of root, fresh weight (FW) of wheat, activity of root, root number and relative water content (RWC) were decreased obviously. Salt resistant varieties had higher germination and germination potential than salt-sensitive variety; the decreased extents of its other index were lower than common wheat. Hence, Salt resistant variety has higher germination and ability of tolerance to salt than salt-sensitive variety. Different positions had different response to different NaCl concentration. Lower NaCl concentration had more serious inhibitory effect on height of shoot, but higher NaCl solution had more serious inhibitory effect on length of root.2 Accumulation of osmoticaUnder salt stress, osmotic ability had significant different among different wheat vultivar. With the increasing of NaCl concentration, content of praline (pro) and soluble protein (sp) in wheat seedling was increased while soluble sugar of salt-sensitive variety was declined, salt resistant variety had not change. The increased extent of pro and sp of salt-resistant variety was higher than salt-sensitive variety. Time appearing peak value of pro in TS9818 was more delayed than other variety under salt stress; we indicated that salt-resistant variety was rapidly responds to salt stress. It was obvious that through accumulating many osmotica salt-resistant variety was able to withstand osmotic stress, which keep higher RWC of wheat seedling and normal physiology metabolize of cell, it was a major factor to resist salt stress.3 Accumulation and distributing of ion in wheat seedlingWith the increasing of NaCl concentration, contents of Na~+,K~+ and Cl~- in shoot and root of four wheat variety were increased while the ratios of wheat K~+/Na~+ were inhibited. With prolonging of treatment time, content of Na~+ and Cl~- in wheat was increased while the K~+ content and ratios of wheat K~+/Na~+ were declined. Salt-resistant variety has not higher K~+ and lower Na~+,Cl~- contents, but by increasing lower of Na~+ and Cl~-, higher increased extents K~+ and decreased extents of K~+/Na~+, salt resistant decreased ion stress to wheat seddling. Compared with same variety, root had more higher content of Na~+,Cl~- and lower K~+ content, ratio of K~+/Na~+.4 The system of antioxidant enzymesThe content of MDA in wheat seedling was increased with the increasing of NaCl concentration and prolonging of treatment time, that in TS9818 incr- eased rapidly, the increased extent in TS9818 were markedly higher than in DK961. As a result, cell membrane of TS9818 was damaged significantly more than DK961. Different antioxidant enzyme had different responds to salt stress. The activity of SOD is enhanced by salt treatment in wheat seedling; activities of POD, CAT and APX in different varieties had different resp- onse to different NaCl concentration. With treatment time persistence from 3 to 13d, the activities of POD in four wheat varieties were enhanced while that of SOD and APX was decreased. Obviously, the role of three enzymes in the process each stage is not dissimilar. SOD and APX play role in the earlier period bigly, but the function of POD which gets up in the later period is bigger. In entire process of stress, the activities of POD and CAT in salt-resistant variety always were higher than the common wheat. Hence, the activities of POD and CAT are close to anti-salt.5 Endogenous hormones Salt stress caused the increase of ABA contents of wheat seedlings. The contents of ABA in TS9818 accumulated were more than in DK961. The contents of IAA in seedlings decreased with increased salt concentration in both cultivars. The IAA content of seedlings in DK961 was more than that in TS9818.The salt stress made the GA3 content of seedlings to decrease in both cultivars. The difference in contents of GA3 roots and shoots existed between two cultivars grown in salt stress. Under the conditions of salt stress, the contents ZR in seedlings rose with the increase of salt concentration and dropped with prolongation of salt stress duration. ZR content in roots of DK961 was quickly translated to shoots for promoting growth, which was more quickly DK961 than TS9818. The ratios of IAA to ABA, GA3 to ABA and ZR to ABA changed with the increase of salt concentration. The ratios of IAA to ABA and GA3 to ABA in both roots and shoots appeared dropping trend with increased salt concentration and the prolongation of salt stress duration in both cultivars. The ratios of IAA to ABA and GA3 to ABA in DK961 were higher than those in TS9818. The ratio of ZR to ABA changed due to salt concentration and cultivars. Those results mentioned above suggested that salt resistant variety has an ability of regulating endogenous hormone contents to adapt salt stress. This leaded salt resistant variety accumulated less ABA and more IAA than salt-sensitive variety under salt stress. Salt resistant variety kept higher ratios of IAA to ABA, GA3 to ABA than salt-sensitive variety under the condition of higher salt concentration stress, which was considered an important reason why seedlings growth of salt resistant variety was less inhibited than salt-sensitive variety by salt stress.6 Accumulation and distributing of ion in wheatThe experiment were conducted to study the relation between salt resista- nce and the transformation of K~+ content,Na~+ content,K~+/Na~+ ratio of different wheat genotypes under two different soil salt concentration at different stage.The K~+ content and Na~+ content and Cl~- content increased while the K~+/Na~+ ratio descended significantly because the increasing scope of K~+ content was lower than that of Na~+ content. Na~+ content of root was more bigger than the other organs in elongatine,flowering and filling stage, so that decent transport to shoot. The distribution of K~+ content and Na~+ content in wheat genotypes were changed according to different growth season,the K~+/Na~+ ratio of shoot was higher than that of root in elongatine stage.In flowering stage,the sorting sequence of K~+/Na~+ ratio was young spike,flag leaf> the other leaf > straw>root. In filling stage,K~+/Na~+ ratio of seed was bigger than that of flag leaf while K~+/Na~+ ratio of flag leaf was bigger than that of the other leaves which was bigger than that of straw.The result above showed that the ability of resistant to salt of vigorous organ was stronger than the other organs.In general,different wheat variety had different K~+ and Na~+ content and ratio of K~+/Na~+, salt resistant genotypes had higher increased am- ount of K~+ content and lower increasing scope of Na~+ and Cl~- ,so that had higher K~+/Na~+ ratio.7. Agricultural character and yieldThe average value of different agronomic characters dropped along with the increasing of soil salt concentration,but different genotypes had different responses. Salt resistant had higher yield of per spike. Content of starch and protein of different wheat had different responds to salt stress. Under salt stress, amylose and protein content of DK961were increased while amylosepectin and starch content and ratio of Ap/Am were reduced; amylose, amylosepectin and starch content of JN17 were enhanced while protein content and ratio of Ap/Am were inhibited. Obviously, the different wheat had different grain quality under different treatment; starch content of salt-resistant wheat was inhibited while protein content was enhanced. Common wheat had opposite trend.
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