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以Ｇｕｎｎｅｒａ／Ｎｏｓｔｏｃ共生体为材料，研究、比较了碳水化合物和Ｈ２对其固氮活力及呼吸速率的影响，结果表明，在正常条件下，外源Ｈ２可提高Ｇｕｎｎｅｒａ／Ｎｏｓｔｏｃ共生体固氮活力近１００％，却使其呼吸速率下降近５０％；而碳水化合物（葡萄糖）也可使其固氮活力提高约１００％，并使其呼吸速率提高近１６０％。表明碳水化合物及Ｈ２均可为Ｇｕｎｎｅｒａ／Ｎｏｓｔｏｃ共生体提供固氮过程的还原力。由于Ｈ２的循环利用降低了呼吸速率，所以就间接地节约了Ｇｕｎｎｅｒａ／Ｎｏｓｔｏｃ共生体固氮过程中对碳水化合物的消耗。结果还表明，碳水化合物（葡萄糖）对恢复饥饿后的Ｇｕｎｎｅｒａ／Ｎｏｓｔｏｃ共生体固氮活力的作用优于外源Ｈ２。
Using Gunnera / Nostoc symbionts as material, the effects of carbohydrates and H2 on its nitrogen fixation activity and respiration rate were studied. Exogenous H2 increased the nitrogen fixation activity of Gunnera / Nostoc symbiont nearly 100% under normal conditions, , But decreased its respiration rate by nearly 50%. Carbohydrate (glucose) also increased its nitrogen fixation activity by about 100% and increased its respiration rate by nearly 160%. It shows that carbohydrates and H2 can all provide the reducing power of Gunnera / Nostoc symbiont to fix nitrogen. As the recycle of H2 reduces the respiration rate, the carbohydrate consumption of Gunnera / Nostoc symbionts during nitrogen fixation is indirectly saved. The results also showed that the effect of carbohydrates (glucose) on the nitrogen fixation activity of Gunnera / Nostoc symbionts after starvation was better than that of exogenous H2.