耐盐促生菌筛选鉴定及对盐胁迫燕麦生长的影响

Screening and Identification of Salt-tolerant Growth Promoting Rhizobacteria and its Effects on Oat Growth under Salt Stress

为获得耐盐促生菌资源,探究对盐胁迫燕麦(Avena sativa L.)的促生作用。用选择性功能培养基复筛黑果枸杞(Lycium ruthenicum Murr.)根系的促生菌,16S rDNA分子生物学技术确定分类学地位。测定接种促生菌对燕麦根系形态、株高及地上生物量的影响。获得目标菌株2株,LrM1固氮酶活性117.0 nmol C2H4·h^(-1)·mL^(-1),溶无机磷量40.0 mg·L^(-1),分泌indole-3-acetic acid(IAA)30.0μg·mL^(-1),无产1-aminocyclopropane^(-1)-carboxylic acid(ACC)脱氨酶特性,耐盐性为9%,经鉴定为Paenibacillus peoriae;LrM2固氮酶活性280.0 nmol C_(2)H_(4)·h^(-1)·mL^(-1),溶无机磷量5.6 mg·L^(-1),具有产ACC脱氨酶的特性,耐盐性达11%,经鉴定为Bacillus属。不同盐浓度下各促生菌对燕麦的促生效果差异显著(P<0.05),LrM2在0.6%NaCl胁迫时显著促进总根长、根表面积、根体积和根尖数增加,株高和鲜重分别增加21.9%和24.7%(P<0.05)。LrM2有多种促生特性和高耐盐性,能够促进盐胁迫下燕麦的生长,具有开发成盐碱地微生物肥料的潜力。

To obtain the resources of salt-tolerant plant growth-promoting rhizobacteria(PGPR),and to explore its growth-promoting effects on oats under salt stress.Using selective functional medium to screened PGPR which isolated from the roots of Lycium ruthenicum L.,and identified by 16S rDNA molecular biology.Effects of PGPR inoculation treatment on root morphology,shoot length and shoot fresh weight of oat were determined.Two target strains were screened,LrM1 was identified as Paenibacillus peoriae,solubility of inorganic phosphate was 40.0 mg·L^(-1),production of IAA was 30.0 mg·L^(-1) and the nitrogenase activity was 117.0 nmol C2H4·h^(-1)·mL^(-1),didn’t produce 1-aminocyclopropane^(-1)-carboxylic acid(ACC)deaminase.LrM2 was identified as Bacillus sp.,solubility of inorganic phosphate was 5.6 mg·L^(-1)and nitrogenase activity was 280.0 nmol C_(2)H_(4)·h^(-1)·mL^(-1),was able to produce ACC deaminase.The growth-promoting effects of various bacteria on oat at different salt concentrations were significantly different(P<0.05).LrM2 significantly increased root length,root surface area,root volume,and root tips number under 0.6%NaCl stress,shoot length and shoot fresh weight increased by 21.9%and 24.7%,respectively(P<0.05).The strain LrM2 has a variety of growth-promoting properties and high salt tolerance,which can promote the growth of oat under salt stress,and has the potential to be developed as microbial fertilizer in saline-alkali soil.