中文摘要：

以1-氨基环丙烷-1-羧酸（ACC）为唯一氮源,采用定向富集筛选方法,从盐碱地燕麦的根际土中筛选出2株具有ACC脱氨酶活性的植物促生菌A-2和A-4,经生理生化和16SrDNA鉴定,确定A-2为肠杆菌属,A-4为假单胞菌属。ACC脱氨酶活性分别为（1.89±0.12）μmolα-KA/（mg Pr.h）和（2.63±0.12）μmolα-KA/（mg Pr.h）;随着色氨酸（L-Trp）浓度的增加,A-2的IAA合成量相应增加,A-4的合成量几乎没改变;A-2合成嗜铁素的能力高于A-4。用A-2及A-4处理的燕麦株高由12.24cm增加到13.98和14.07cm;植株鲜重由34.29g增加到35.01和35.10g;植株根长由14.13cm增加到16.23和17.60cm;根鲜重由7.79g增加到8.07和8.19g。说明用具有ACC脱氨酶活性的菌株A-2和A-4处理可有效地促进燕麦的生长并提高燕麦的盐碱抗性。

英文摘要：

Two strains of plant growth-promoting rhizobacteria（PGPR） containing ACC deaminase,A-2 and A-4 were isolated from saline-alkali rhizosphere soil of Avena sativa,based upon their ability to utilize 1-aminocyclopropane-1-carboxylate（ACC） as a sole nitrogen source.Using morphology,physiological biochemical characteristics and 16S rDNA analysis,strain A-2 was identified as Enterobacter sp.and A-4 was confirmed as Pseudomonas sp..The ACC deaminase activity of A-2 and A-4 were（1.89±0.12） μmol α-KA/（mg Pr·h） and（2.63±0.12） μmol α-KA/（mg Pr·h）,respectively.When the concentration of L-Trp increased,the IAA synthesis of A-2 increased,while that of A-4 did not change significantly.The ability of A-2 to synthesize siderophore was greater than that of A-4.The height of oat plants treated with A-2 and A-4 were from 12.24 cm up to 13.98 and 14.07 cm,the plant fresh weights were from 34.285 g up to 35.012 and 35.102 g,respectively.The length of roots were from 14.13 cm up to 16.23 and 17.60 cm,and root fresh weights were from 7.790 g up to 8.065 and 8.187 g,respectively.These results suggest that strains A-2 and A-4 contain ACC deaminase that can increase resistance in oat to saline-alkali stress.