Partitioning of 13C-labelled photosynthate varies with growth stage and panicle size in high-yielding rice
Partitioning of 13C-labelled photosynthate varies with growth stage and panicle size in high-yielding rice
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DOI：
10.1071/fp03177
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发表时间：
2004-01-01
影响因子：
3
通讯作者：
Fujita, K
中科院分区：
文献类型：
--
作者：
Mohapatra, PK;Masamoto, Y;Fujita, K
超高产水稻（Oryza sativa L.）在田间条件下，栽培品种Takanari和传统的粳稻品种Nakateshinsenbon，以比较C-13标记的光合产物在生殖发育期间向不同植物器官的分配。将旗叶和主秆上紧挨着旗叶的两片叶单独暴露于（CO_2）-C-13，并评估重碳同位素向籽粒、船体、穗枝和植物营养部分的移动。此外，通过去除穗的一些一级分枝，研究了减少库大小对C-13分配到不同器官的影响。C-13在抽穗后被三叶吸收，主要向穗粒和船体转移。在这一时期，最上部的三片叶和穗由单一的源库单元组成。分配的C-13的植物的营养结构的其余部分是最小的。在中田新仙本的情况下，旗叶提供了大部分的碳同化物的籽粒和其他两个叶的贡献要小得多。然而，在高成，C-13的贡献，从第二叶的籽粒相当于旗叶。在高成，去除三分之一以上的主枝的穗显着减少分配从第三叶的秆，但分配从旗叶没有显着变化。相反，去除分支处理显着抑制碳同化物的运输从剑叶在Nakateshinsenbon。本文讨论了水稻源库关系的必然性.因此，在低产的传统水稻中，剑叶光合作用为发育中的籽粒提供碳同化物。但在超高产水稻高成中，主源区被扩展到包括剑叶以下的两片叶，以维持特大穗。如果进一步扩大种植面积，超高产水稻的籽粒充实程度可能会更高。
A super-high-yielding rice ( Oryza sativa L.) cultivar, Takanari, and a traditional japonica rice cultivar, Nakateshinsenbon, were grown under field conditions to compare partitioning of C-13-labelled photosynthate to different plant organs during the period of reproductive development. The flag leaf and the two leaves immediately below it on the main culm were exposed individually to (CO2)-C-13 and the movement of the heavy carbon isotope to grains, hull, panicle branches and vegetative parts of plant was assessed. Also, the effect of a reduction of sink size on the partitioning of C-13 to different organs was studied by removing some of the primary branches of the panicle. C-13 taken up by the three leaves in the post-heading period, moved mostly to the grains and hull of the panicle. At this stage, the uppermost three leaves and the panicle consisted of a single source - sink unit. Partitioning of C-13 to the rest of the vegetative structures of the plant was minimal. In the case of Nakateshinsenbon, the flag leaf supplied most of the carbon assimilates for the grains and contributions from the other two leaves were much smaller. However, in Takanari, the contribution of C-13 to grains from the second leaf was equivalent to that of the flag leaf. In Takanari, removal of more than one third of the primary branches of the panicle significantly reduced partitioning from the third leaf of the culm, but partitioning from the flag leaf was not significantly changed. In contrast, branch removal treatment significantly depressed transport of carbon assimilates from the flag leaf in Nakateshinsenbon. The obligatory nature of the source - sink relationship in rice is discussed. It is concluded that in lower-yielding traditional rice, photosynthesis in the flag leaf supplies carbon assimilates to the developing grains. But in the super-yielding rice Takanari, the main source area is extended to include the two leaves below the flag leaf so as to sustain an extra large panicle. Even greater grain-filling is possible in super-yielding rice, if the source area is increased further.