| Soil salinization is one of the main abiotic stress factors affecting crop yields.The germination and seedling stages are the periods of wheat life when they are more sensitive to salt stress.Alleviating the salt damage of wheat at the germination stage and seedling stage,and promoting seed germination and seedling construction under salt stress are of great importance to increasing wheat production and income.In this study,wheat was used as the test material,germination test was carried out under different salt concentrations,the germination index and physiological index of wheat seeds were determined,and the effects of different salt concentrations on different wheat varieties were determined;the growth regulators such as BR,GABA,TDZ and other growth regulators were selected,and the effects of different exogenous regulator treatments on wheat seed germination and seedling growth under salt stress were studied,and the appropriate exogenous regulator treatment（1.5mg/L BR,100 mg/L TDZ seed mixing）further determined the soluble sugar content and SOD activity changes in wheat seed germination under salt stress,explored the mechanism of action of exogenous regulators to alleviate salt damage at wheat germination and seedling stage,and provided theoretical basis and technical support for improving wheat sowing quality and ensuring wheat yield and income increase.The findings are as follows:1.Effects of different salt concentrations on germination vigor of wheat seedsFour wheat varieties,SN23,JM22,LY502 and SL02-1,were selected and the germination test was carried out under different salt concentrations（0,0.3%,0.6%,0.9%）,respectively,and the results showed that the germination index,dry weight and vigor index of each variety were significantly reduced by the salt stress of different concentrations.The 0.3%and 0.6% salt stress had no significant effect on the germination percentage of the four cultivars,and only 0.9% salt stress significantly reduced the germination percentage of SN23 and JM22.On the whole,SN23 and LY502 show that each germination index is greatly affected by salt stress,and the reduction of each index is significantly larger.The germination energy and germination percentage of JM22 was greatly affected by salt stress,and the remaining indicators were relatively less affected.The germination energy,germination index and decline of SL02-1 under salt stress were small,and they showed good salt tolerance.2.Effects of exogenous regulator-induced and seed mixing treatment on wheat germination and seedling formation under salt stressDA-6,BR,GABA and TDZ were used to induce and mix seeds of SN23 seeds,and the results showed that the 1.5 m M GABA and 2.5 m M TDZ initiation treatments could significantly improve the germination energy,germination index and vigor index of SN23 and alleviate salt damage.The effect of the exogenous growth regulator compound for initiation treatment was not significant compared with the treatment of a single regulator,and there was no significant effect on the vigor index.The effects of four exogenous regulator seed mixing treatments on the germination vigor of wheat seeds under salt stress were studied,and the results showed that the 1.5 mg/L BR and 100 mg/L TDZ seed mixing treatments could significantly improve the germination energy,dry weight of each plant,germination index and vigor index of SN23 under salt stress conditions,and alleviate salt damage.The effect of the exogenous regulator compounding for seed mixing treatment is not significant compared with the single modulator treatment to improve germination vigor.3.The regulatory effect of exogenous regulator treatment on the germination of wheat seedlings under different conditionsThe effects of TDZ and BR seed mixing treatment on the germination of two wheat varieties SN23 and LY502 under normal conditions and salt stress were studied,and the results showed that the regulatory effect of TDZ seed mixing on the germination of the two varieties was relatively consistent,and it could promote germination and seedling formation under normal conditions and salt stress.The 100 mg/L TDZ treatment significantly improved the germination energy,germination index,dry weight and vigor index of two wheat varieties under normal and salt stress,and had no significant effect on the germination rate of both varieties under normal conditions and salt stress.The 1.5 mg/L BR seed mix had a good role in promoting germination under the normal growth conditions of SN23,significantly improving its germination index,dry weight,and vigor index,and having a good role in promoting the germination of seedlings under normal and salt stress of LY502,and significantly improving the germination index,dry weight of a single plant and the germination energy and vigor index under salt stress under normal conditions.4.Effects of exogenous regulator treatment on physiological indices of wheat seedlings under salt stressThe changes of TDZ and BR seed mixing treatment on wheat seeds under normal conditions and salt stress were studied.The results showed that the 100 mg/L TDZ seed mixing treatment had a significant effect on the SOD activity of the two wheat varieties under normal conditions and during seed germination under salt stress,and the soluble sugar content during germination under the normal conditions of both varieties was significantly improved,and the soluble sugar content during germination of SN23 under salt stress was also significantly improved.The 1.5 mg/L BR seed mixing treatment significantly improved the SOD activity of the two cultivars during normal germination,and also significantly increased the SOD activity in the stress germination of SN23,and significantly increased the soluble sugar content of SN23 during germination under normal conditions,and also significantly increased the soluble sugar content of LY502 in germination under salt stress.In summary,the 100 mg/L TDZ seed mixing treatment has a good effect on wheat germination under normal conditions and salt stress,and significantly increases the SOD activity and soluble sugar content during seed germination,indicating that the TDZ seed mixing treatment enhances the salt tolerance of wheat seeds during germination.The effect of1.5 mg/L BR seeding to increase seed germination and seedling formation varies from cultivar to cultivar,and the effect of promoting germination under normal conditions and salt stress conditions is not consistent.Therefore,it is believed that the 100 mg/L TDZ seed mixing treatment can be used as an effective treatment for the regulation of germination seedlings under wheat salt stress. |
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