Nitrogen from senescing lower leaves of common bean is re-translocated to nodules and might be involved in a N-feedback regulation of nitrogen fixation
Nitrogen from senescing lower leaves of common bean is re-translocated to nodules and might be involved in a N-feedback regulation of nitrogen fixation
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DOI：
10.1016/j.jplph.2006.03.017
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发表时间：
2006-10-01
影响因子：
4.3
通讯作者：
Schulze, Joachim
中科院分区：
文献类型：
--
作者：
Fischinger, Stephanie A.;Drevon, Jean-Jacques;Schulze, Joachim
本研究的目的是为了阐明从下部叶片的再动员N是否参与导致普通菜豆（Phoseolus vulgaris L.）结荚期间N-2固定的下降。此外，我们还讨论了从下部叶片再活化的N是否会到达根瘤的问题。结瘤的菜豆植物在石英砂中的生长室中生长。在2周的时间内，在营养生长和生殖生长，50%的叶（下半部分）被切除或单独变暗，从而消除了相同的光合能力，但允许N从变暗的叶中再动员。此外，在营养生长期，在施加暗化处理之前，通过施用（NH_4 NO_3）-N-15来标记每株植物的三片下部叶片。营养生长期叶片变暗诱导N再活化，同时降低N-2固定率和生长。生殖生长期切叶增强了N-2固定。在所有情况下，N-2固定率的变化是生长速率改变的结果，白色的% N在整个植物和植物的各个部分保持保守。直接叶片labetting后，但也在营养生长期结束时，大量的N-15从叶片中可以回收的控制中的结节，并在更高的量在叶变暗处理。有人建议，氮从叶片内循环植物通过结节，这种循环流的强度或组成可能是一个假定的N-反馈效应的信号。(c)2006年Elsevier GmbH。All rights reserved.
The objective of the present study was to elucidate whether remobilized N from lower leaves is involved in causing the drop in N-2 fixation during pod-filling in common bean (Phoseolus vulgaris L). Moreover, we addressed the question of whether remobilized N from lower Leaves would reach the nodules. Nodulated common bean plants were grown in a growth chamber in quartz sand. During a 2-week period, at vegetative and at reproductive growth, 50% of the Leaves (lower part) were either excised or individually darkened, thereby removing the same photosynthetic capacity yet allowing N to be remobilized from the darkened leaves. Moreover, at the vegetative growth period, three lower leaves per plants were N-15 labelled by applying (NH4NO3)-N-15 prior to imposing the darkening treatment. Leaf darkening at vegetative growth induced N remobilization as welt as reduced N-2-fixation rates and growth. Leaf excision at reproductive growth enhanced N-2 fixation. Changes in N-2-fixation rates were in all cases the result of altered growth rates, white the % N in the whole plant and in various plant parts remained conserved. Directly after leaf labetting, but also at the end of the vegetative growth period, substantial amounts of N-15 from the leaves could be recovered in nodules in the control, and in higher amounts in the leaf-darkening treatment. It is proposed that nitrogen from leaves circulates within the plant via nodules, and that the strength or composition of this circular flow may be the signal for a putative N-feedback effect. (c) 2006 Elsevier GmbH. All rights reserved.