【摘要】 液体培养和深层琼脂固体培养,都表明浑球红假单胞菌在黑暗微好氧条件下能够依靠固定 N₂生长.在光照和黑暗有氧条件下,菌株的乙炔还原活性都能出现,但在光照情况下细胞固氮酶比黑暗时对氧更敏感.进一步实验表明,高浓度氧气不但抑制固氮酶的活性水平,而且使固氮酶活性的出现延迟.根据上述结果,讨论了浑球红假单胞菌的固氮作用与菌体的呼吸代谢及环境氧分压的相互关系.更多还原

【Abstract】 Diazotrophy of R.sphaeroides is not obligatorily linked to photosyn-thesis.In the dark,the capacity of growing for R.sphaeroides with N₂ as solenitrogen surce was demonstrated in deep agar shake cultures.R.sphaeroides canalso synthesize nitrogenase and fix dinitrogen under microaerobic conditions inliquid culture.Acetylene reduction by whole cells is more sensitive to oxygen inthe light than in the dark,and nitrogenase activity appears later and lower withthe presence of higher O₂ content（5%—20%）under either of the conditions.更多还原