关键词: 小麦, 盐胁迫, 土壤微生物, 种子萌发, 幼苗生长

Abstract: 【Objective】To investigate the effects of in situ soil microbial communities on wheat seed germination and seedling growth under salt stress.【Methods】Jimai 22 （J22,a conventional variety） and Jimai 44（J44,a salt-tolerant variety） were used as experimental materials. Three salt concentration gradients were established：0 mmol/L（no stress）,75 mmol/L（moderate salt stress）,and 200 mmol/L（severe salt stress）. At the same time,two treatments were set：inoculation with deionised water（CK） and in situ soil microbial inoculum（microbial inoculation,G）. By measuring seed germination rate,germination energy,maximum bud length,main root length,as well as root weight and seedling weight of wheat seedlings,the promoting effects of soil microorganisms on wheat seed germination and seedling growth under salt stress were analyzed.【Results】With the increase of salt concentration,the average germination rates of wheat seed decreased from 97.50% to 62.52%. From no stress to severe salt stress,the average germination energies of the two varieties decreased from 96.66% to 22.97%,the average main root lengths decreased from 13.90 cm to 5.70 cm,and the average seedling weights decreased from 0.16 g to 0.10 g. The germination rates of J44 and J22 seeds under moderate and severe salt stress conditions were 98.34%,66.67%,and 91.67%,55.79%,respectively,with a extremely significant differences between the two varieties（P<0.001）. Microbial inoculation promoted wheat seed germination and seedling growth,and the effect was more significant under salt stress conditions. Under severe salt stress,the germination rates of J22 and J44 were 57.06% and 67.98%,the maximum bud lengths were 11.26 cm and 11.32 cm,and the main root lengths were 7.34 cm and 7.33 cm,respectively,all extremely significantly higher than those of CK（P<0.01 or P<0.001）;the root weights increased extremely significantly compared with CK,with increases of 162.40% and 93.60%,respectively（P<0.001）. Significant or extremely significant positive correlations were observed between germination indicators and seedling growth indicators of wheat（P<0.05 or P<0.01）,with the correlation coefficient of 0.819 between germination rate and seedling weight.【Conclusion】Salt stress inhibites wheat seedling growth to a certain extent. The salt-tolerant variety Jimai 44 performes better than the conventional variety Jimai 22. Soil microorganisms can effectively promote seed germination,increase seedling biomass,and help wheat cope with salt stress.

Key words: Wheat, Salt stress, Soil microorganisms, Seed germination, Seedling growth