玉米内生固氮菌的分离鉴定及对小麦幼苗的促生效应

应用研磨法从健康玉米植株的根茎叶中分离到4株具有高固氮酶活性的内生菌,根据它们在植物组织来源和分离时稀释度的不同将其分别命名为L1A1、L1A4、L1B9和L2A2(L代表来源于叶片,A代表10倍稀释,B代表100倍稀释).经形态学、生理生化特性及16S rDNA序列分析,对4株菌鉴定结果表明,L1A1为约氏不动杆菌(Acinetobacter johnsonii)、L1A4为Sphingomonas panni、L1B9为Sphingomonas yabuuchiae、L2A2为巴氏葡萄球菌(Staphylococcus pasteuri).这4株菌均具有不同程度的固氮酶活性和产IAA(吲哚乙酸)能力,其中L1A1、L2A2具有降解有机磷能力,L1A4具有体外拮抗小麦赤霉病菌的能力.接种这4株菌的小麦苗高、根长、鲜质量、干质量和叶绿素含量均比未接菌小麦高(P＜0.05),说明其具有促进小麦幼苗生长的作用.

Isolation and Identification of Endophytic Diazotrophic Bacteria from Maize and Their Effect on Wheat Seedling Growth

Four strains of endophytic diazotrophic bacteria were isolated from root,stalk and leaf of maize using the grinding method.According to the isolated plant tissues and dilution multiples,the four strains were named as L1A1,L1A4,L1B9 and L2A2.They were identified as Acinetobacter johnsonii,Sphingomonas panni,Sphingomonas yabuuchiae and Staphylococcus pasteuri respectively by way of morphological,physiological-biochemical properties and 16S rDNA sequence analysis.All the strains possessed nitrogenase activity and could produce IAA more or less.Isolates L1A1 and L2A2 had phosphate solubilization ability.L1A4 showed antagonism against Fusarium graminearum.When inoculated the endophytic diazotrophic bacteria on wheat,they showed a statistically significant increase(P<0.05) in seedling height,root length,fresh weight,dry weight and Chlorophyll content.