Dynamics of Light and Nitrogen Distribution during Grain Filling within Wheat Canopy
Dynamics of Light and Nitrogen Distribution during Grain Filling within Wheat Canopy
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DOI：
10.1104/pp.108.124156
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发表时间：
2008-11-01
期刊：
影响因子：
7.4
通讯作者：
Andrieu, Bruno
中科院分区：
文献类型：
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作者：
Bertheloot, Jessica;Martre, Pierre;Andrieu, Bruno
在一次结实的物种中，在生殖阶段，生长的谷粒代表氮（N）的强库，并触发营养器官的N再动员，从而降低冠层光合作用并加速叶片衰老。生殖冠层中氮的时空分布还没有详细描述。在这里，我们研究了当地的光环境的作用，在田间生长的小麦（Triticum aestivum）籽粒灌浆过程中的叶片N质量每单位叶面积（SLN）的时空分布。此外，为了提供一些洞察到不同营养器官之间的协调N耗尽，N动态进行了研究，为个人叶片，叶鞘，节间，和谷壳的顶部可育秆。在冠层尺度上，SLN的分布使旗叶颈以下的光梯度减小，直至灌浆末期。相反，旗叶叶片沿着的显著光梯度与SLN梯度无关。在顶部肥沃的秆，总（活1坏死组织）N浓度的不同层和鞘的时间过程中表现出类似的模式。另一种常见的模式是观察节间和谷壳。在此期间，没有根N吸收，N消耗的个别叶片和鞘遵循一级动力学独立的叶龄，基因型，或N营养。这里提出的结果表明，在灌浆过程中，N动态集成在秆尺度上，强烈依赖于当地的冠层结构所确定的光照条件。
In monocarpic species, during the reproductive stage the growing grains represent a strong sink for nitrogen (N) and trigger N remobilization from the vegetative organs, which decreases canopy photosynthesis and accelerates leaf senescence. The spatiotemporal distribution of N in a reproductive canopy has not been described in detail. Here, we investigated the role of the local light environment on the spatiotemporal distribution of leaf lamina N mass per unit leaf area (SLN) during grain filling of field-grown wheat (Triticum aestivum). In addition, in order to provide some insight into the coordination of N depletion between the different vegetative organs, N dynamics were studied for individual leaf laminae, leaf sheaths, internodes, and chaff of the top fertile culms. At the canopy scale, SLN distribution paralleled the light gradient below the flag leaf collar until almost the end of grain filling. On the contrary, the significant light gradient along the flag leaf lamina was not associated with a SLN gradient. Within the top fertile culms, the time course of total (alive 1 necrotic tissues) N concentration of the different laminae and sheaths displayed a similar pattern. Another common pattern was observed for internodes and chaff. During the period of no root N uptake, N depletion of individual laminae and sheaths followed a first-order kinetics independent of leaf age, genotype, or N nutrition. The results presented here show that during grain filling, N dynamics are integrated at the culm scale and strongly depend on the local light conditions determined by the canopy structure.