镧与钕对红假单胞菌的生长、类胡萝卜素生成及固氮活性的影响

EFFECTS OF La^3+ AND Nd^3+ ON THE GROWTH, CAROTENE CONTENT AND NITROGENASE ACTIVITY OF RHODOPSEUDOMONAS SP.

本文报道了不同浓度的La^(3+)和Nd^(3+)对红假单胞菌(Rhodopseudomonas sp.)的细胞形态、生长、类胡萝卜素生成和固氮活性的影响。LaCl_3在25和50mg/L时对红假单胞菌的细胞生长有轻微刺激作用;当浓度高于75mg/L时有抑制作用,随浓度的提高而抑制作用增强,细胞缩小;NdCl_3在25和50mg/L时对该菌细胞生长有轻微抑制作用,高于75mg/L时抑制作用明显增强,细胞缩小。两种稀土元素在25和50mg/L时对该菌类胡萝卜素的生成有刺激作用,高于75mg/L时则有抑制作用。La^(3+)在0～100mg/L,Nd^(3+)在0～75mg/L时对固氮酶活性有刺激作用,La^(3+)和Nd^(3+)分别高于100mg/L和75mg/L时则有抑制作用,并随浓度的增高,抑制作用明显增强。

The effects of La3+ and Nd3+ on the growth, carotene content and nitrogen fixation of Rhodopseudomonas sp. were studied. The experimental data showed that lower concentrations (<50mg/L) of both LaCl3 and NdCl3 barely slightly sti-munlated cell growth and its carotene content of Rhodopseudomonas sp., and higher concentrations (>75 mg/L) inhibited the growth and carotene content. The nitro-genase activity of Rhodopseudomonas sp. was increased distinctly when the concentration of both LaCl3 and NdCl3 at 75 mg/L, and decreased as the concentration incre-ased.