【摘要】 从新疆鄯善迪砍儿乡砂地生长的玉米根际分离到一株联合固氮菌Ｋ１９－１，经鉴定为植生克雷伯氏菌（Ｋｌｅｂｓｉｅｌｌａ ｐｌａｎｔｉｃｏｌａ）。Ｋ１９－１ 在４０℃，于无氮培养基上生长良好，并具有乙炔还原及１５Ｎ２ 还原能力。ｎｉｆＨ ｐｒｏｍ ｏｔｅｒ∶ｌａｃＺ融合子在Ｋ１９－１ 中的表达在４０℃不受阻抑。ＮＨ＋４ 不抑制Ｋ１９－１ 的固氮酶活性，但阻抑ｎｉｆＨ ｐｒｏｍ ｏｔｅｒ∶ｌａｃＺ融合子在Ｋ１９－１ 中的表达。Ｋ１９－１ 在厌氧条件下具有固氮活性，在氧浓度增至４％ 时固氮酶活性仍不受抑制，而ｎｉｆＨ ｐｒｏｍ ｏｔｅｒ∶ｌａｃＺ融合子在Ｋ１９－１ 中的表达亦不受氧阻抑更多还原

【Abstract】 A strain K19 1 was isolated from maize roots grown in sand of Xinjing Autonomous region.It was identified as Klebsiella planticola.K19 1 could grow on N 2 free medium at 40℃ and reduce acetylene and 15 N 2 at 40℃.The nifH promoter: lacZ fusion was expressed in K19 1 at 40℃.NH + 4 did not inhibit Nase activity but repressed the expression of nifH lacZ fusion in K 19 1.K 19 1 could fix nitrogen anaerobically but Nase activity was still not inhibited till O 2 concentration was increased to 4%.The expression of nifH: lacZ fusion in K 19 1 was not repressed by O 2.更多还原