SIGNIFICANCE OF BACTERIAL‐ANABAENA (CYANOPHYCEAE) ASSOCIATIONS WITH RESPECT TO N2 FIXATION IN FRESHWATER 1, 2
SIGNIFICANCE OF BACTERIAL‐ANABAENA (CYANOPHYCEAE) ASSOCIATIONS WITH RESPECT TO N2 FIXATION IN FRESHWATER 1, 2
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细菌-鱼腥藻（蓝藻科）关联对于淡水中 N2 固定的意义 1, 2
DOI：
10.1111/j.1529-8817.1978.tb00295.x
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发表时间：
1978
影响因子：
2.9
通讯作者：
P. Kellar
中科院分区：
文献类型：
--
作者：
H. Paerl;P. Kellar
研究了蓝绿藻和细菌之间的特定关联的功能方面，使用了自然发生的和人工培养的蓝藻物种。在水体中，细菌与水藻杂胞相关联，细菌对多种氨基酸和葡萄糖表现出趋化反应。早期放射自显像证据表明，与异囊相关的细菌含有相同的底物，这表明相关细菌可能通过利用藻类排泄产物而受益。作为回报，细菌刺激藻类固氮。最可能解释这种刺激的机制似乎是细菌在高环境氧浓度期间在与异囊相邻的微区（< 3 μm直径）中去除氧。在细菌存在的情况下，水藻迅速克服了抑制氮酶的氧气浓度。无菌培养具有更广泛的氮酶抑制，并且需要更长的时间来恢复对氧合的响应。藻-细菌共生有助于水藻在高氧地表水中同时保持最佳的氮固定和高光合速率。
The functional aspects of specific associations between bluegreen algae and bacteria were investigated using both naturally occurring and cultured species of Anabaena. In take waters where bacteria were associated with Anabaena heterocysls, the bacteria exhibited a chemotactic response to a variety of amino acids and glucose. Earlier autoradiographic evidence that bacteria associated with heterocysts incorporate identical substrates indicates that associated bacteria probably benefit by utilizing algal excretion products. In return, the bacteria stimulate algal N2fixation. The most likely mechanism explaining such stimulation appeared to be bacterial oxygen removal in microzones (< 3 μm diam) bordering heterocysts during periods of high ambient oxygen concentrations. In the presence of bacteria, Anabaena rapidly overcame nitrogenase‐ inhibiting concentrations of oxygen. Axenic cullures had more extensive nitrogenase inhibition, and took longer to recover in response to oxygenation. Algal‐bacterial mutualism aids Anabaena in maintaining concurrent optimal N2 fixation and high photosynthetic rates in highly oxygenated surface waters.