【作者】 李博文；

【导师】 王罡；

【作者基本信息】 天津大学 ， 生物学， 2022， 硕士

【摘要】 盐胁迫严重影响了作物的生长与产量,是制约农业发展的非生物胁迫之一。水稻（Oryza sativa L.）属禾本科稻属,是全球主要的粮食作物。研究表明,硫化氢（Hydrogen sulfide,H₂S）是一种新型的信号分子,有效调节植物生长和发育。耐盐促生菌（Plant growth promoting bacteria,PGPB）也在植物生长、发育及抵御逆境胁迫过程发挥了重要作用。然而,二者联用对胁迫下的植物的生长状况未见报道。因此,本文以水稻幼苗为研究材料,探究了H₂S与PGPB的单独或联合作用对盐胁迫下的水稻生长的影响,结果如下:菌株JIL321和硫氢化钠（NaHS,H₂S前体）提高了盐胁迫下水稻幼苗耐盐性。菌株JIL321可在盐浓度为7.5%Na Cl的液体LB培养基上存活,是一株耐盐的PGPB。菌株JIL321具有促生特性,能够产生吲哚乙酸（Indole acetic acid,IAA）、胞外多糖（Exopolysaccharides,EPS）、1-氨基环丙烷羧酸（1-aminocyclopropane-1-carboxylic acid,ACC）脱氨酶、氨和溶解磷酸盐。根据16S r DNA序列同源性,菌株JIL321被鉴定为Myroides sp.。盆栽实验结果表明,单独的菌株JIL321和NaHS处理不仅有效改善了盐胁迫下水稻幼苗的生长,还提高盐渍土壤的酶活力,改善土壤质量。NaHS与菌株JIL321联合作用进一步促进了盐胁迫下水稻的生长。盐胁迫下,联合处理组水稻的可溶性蛋白、叶绿素含量、过氧化氢酶活性显著提高,导致生物量累积,有效缓解盐胁迫对水稻的损伤。150 m M Na Cl处理下,H₂S预处理将菌株的EPS产量和ACC脱氨酶活力提高了32.12%和17.68%,增强菌株对盐胁迫下水稻耐盐性的影响。NaHS与菌株JIL321的交互作用显著提升了水稻叶和根中内源H₂S的含量,H₂S积极参与对盐胁迫的响应。与单独处理相比,上述指标的提高有效增强水稻幼苗的耐盐性。综上所述,本研究对菌株JIL321的耐盐性和促生特性进行了鉴定,并通过盆栽实验对菌株JIL321、NaHS及H₂S-JIL321联合处理对盐胁迫下水稻生长的影响进行探究。实验表明,单一菌株JIL321或NaHS处理可缓解盐分对水稻幼苗的抑制,而H₂S介导的菌株促生特性的增强和H₂S对水稻的保护作用赋予了水稻幼苗对盐胁迫更强的抗性。更多还原

【Abstract】 Salinity stress is one of the abiotic stresses that limit agricultural development,as it severely affects the growth and yield of crops.Rice（Oryza sativa L.）is a global crop staple.Hydrogen sulfide（H₂S）is a novel signaling molecule that regulates plant growth and development.Also,plant growth promoting bacteria（PGPB）play an important role in plant growth,development and resistance to adversity stress.However,the effect of the combined use of the two on the resistance of plants to stress has not been reported.Therefore,the effects of the individual and combined use of H₂S and PGPB on the growth of salt-stressed rice seedlings were investigated in this study.The salt tolerance of salt-stressed rice seedlings was improved by treating with strain JIL321 and sodium sulfide（NaHS,H₂S donor）.Strain JIL321 was a salt-tolerant PGPB that survived on liquid LB medium with a salt concentration of 7.5%Na Cl,and was able to produce indole acetic acid（IAA）,exopolysaccharides（EPS）,1-aminocyclopropane-1-carboxylic acid（ACC）deaminase,ammonia and soluble phosphate.Based on 16S r DNA sequence homology,strain JIL321 was identified as Myroides sp.and its registration number was MZ356500.The individual treatment of strain JIL321 and NaHS not only improved the growth of salt-stressed rice seedlings,but also increased the enzyme activity and quality of saline soil in pot experiments.The growth of salt-stressed rice was increased bythe combined treatment of NaHS and JIL321.The biomass of salt-stressed rice in combined treatment was enhanced by increasing soluble protein,chlorophyll content and catalase activity,alleviating the damage caused by salt stress.The EPS production and ACC deaminase activity of the strain with H₂S pretreatment were increased by 32.12%and 17.68%under 150 m M Na Cl treatment.Interaction between NaHS and JIL321 significantly increased the endogenous H₂S content,which positively participated in the response to salt stress,in rice leaves and roots.Both improvements were found to be effective in enhancing the salt tolerance of rice seedlings compared to the treatments alone.In conclusion,the damage to rice caused by salt stress was reduced by single NaHS and JIL321,whereas the greatest resistance was conferred by the protective effect of H₂S on JIL321 and rice in the combined treatment against that in the single treatment.更多还原