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葡萄糖和氢对Gunnera/Nostoc固氮共生体固氮活力的影响

苘辉民, Silvester W B

莱阳农学院基础部. 山东,莱阳(265200)；维克多大学生物科学系. 海明顿

摘要

Gunnera/Nostoc固氮共生体固氮相对效率(RE)可在0.26-0.80之间变动, 而不是一 个常数。外加1.5%葡萄糖液可使其固氮活力提高约100%, 同时也使组织的呼吸速率提高了近160%。加外源H_(2)可使其固氮活力提高近100%, 但却使组织的呼吸速率降低了近50%。正常生长条件下的组织净放H_(2)量较低, 而外源2%葡萄糖液可使组织净放H_(2)量提高近2倍。外加5mmol/L的NH_(4)Cl溶液可使其固氮活力下降约70%。图6表2参19

关键词： 古奴草／念珠藻共生体; 固氮酶; 固氮相对效率(RE); 吸氢酶、放H_(2); 还原力

Interrelationships of H_(2) and carbon metabolism in controlling and regulating nitrogen fixation activity in the Gunnera/Nostoc symbionts

Man Huimin, Silvester W B

Department of Basic Courses, Laiyang Agricultural College. Laiyang,Shandong

Abstract

The Gunnera/Nostoc symbionts evolved H_(2)through nitrogenase in a predictable manner. However, the relative efficiency of nitrogen fixation in the Gunnera/Nostoc symbionts varied widely from 0.26 to 0.80. Nitrogen fixation activity was carbohydrate-limited in normal growth conditions and glucose addition(1.5%) rapidly increased nitrogen fixation activity and respiratory rate with a maximum stimulation of ca. 100% and 160% respectively. The stimulation of nitrogen fixation activity was also affected by H_(2)addition, when the maximum stimulation of ca. 100% occurred in seriously carbohydrate-limited condition. However, respiration rate decreased by about 50% on H_(2) addition. Net H_(2) evolution was strongly stimulated by slucose addition. In addition, nitrogen fixation activity decreased by about 70% on the addition of NH_(4)Cl. It is postulated that carbohydrate supply and uptake hydrogenase could regulate the activity of nitrogen fixation by supplying a common reductant pool and that the recycling of H_(2) through nitrogenase, when (CH_(2)O)_(n) supply was low, could sustain nitrogenase at a reasonably high level and could thus be able to take advantage of an...

Key words: Gunnera/Nostoc symbiont;Nitrogenase;Hydrogenase;Relative efficiency of nitrogen fixation;Hydropn evolution

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引用本文：

苘辉民, Silvester W B. 葡萄糖和氢对Gunnera/Nostoc固氮共生体固氮活力的影响[J]. 生理学报 1994; 46 (1): .

Man Huimin, Silvester W B. Interrelationships of H_(2) and carbon metabolism in controlling and regulating nitrogen fixation activity in the Gunnera/Nostoc symbionts. Acta Physiol Sin 1994; 46 (1): (in Chinese with English abstract).