To determine whether senescing leaves provoke an active nitrogen (N) remobilization that results in the reduction of nitrogenase activity, 60% of Medicago truncatula lower leaves were either darkened or individually excised for two weeks. Although a considerable amount of N was remobilized, N₂ fixation activity was found to be increased to maintain the N source/sink balance, indicating an absence of the negative N‐feedback regulation of nitrogenase activity in the senescing M. truncatula.

中文翻译：

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氮反馈是否参与了Medi藜苜蓿中固氮酶活性的调节？

为了确定衰老的叶片是否引起活性氮（N）迁移，从而导致固氮酶活性降低，将60％的苜蓿ca藜下部叶片变黑或单独切除两周。尽管N的相当大的量的再活化，N ₂，发现固定活性增加以维持N个源/汇的平衡，表明不存在在衰老固氮酶活性的负的N-反馈调节的蒺藜苜蓿。