Soybean fruit development and set at the node level under combined photoperiod and radiation conditions.
Soybean fruit development and set at the node level under combined photoperiod and radiation conditions.
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DOI：
10.1093/jxb/erv475
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发表时间：
2016-01
影响因子：
6.9
通讯作者：
Kantolic AG
中科院分区：
文献类型：
--
作者：
Nico M;Mantese AI;Miralles DJ;Kantolic AG
花后较长的日照时间推迟了一个节点内优势豆荚的伸长和积极生长，从而延长了开花时间，并使豆荚在通常的优势位置结荚。在大豆中，花后较长的白昼增加了种子数量。这种积极的光周期效应对种子数量的影响与作物周期中积累的辐射量的增加有关，因为长日照延长了作物周期的持续时间。然而，独立于同化物可用性的节内过程的证据表明，节点水平的光周期效应也可能有助于荚果的形成。这项工作的目的是确定在长日照条件下每个节点荚数增加的主要机制；包括开花、荚果发育、生长和在节点水平上设置的动态。长日照增加了主茎上每个节的荚果，这是通过增加一些主茎节的外侧总状花序（通常是优势位置）上的荚果来实现的。长日延长了花期，从而增加了侧总状花序上开放的花的数量。由于初生总状花序（优势位置）有效种子灌浆延迟，在长日照下花期延长。长时间的日照也延缓了花向荚果的发育，并有饱满的种子，延缓了荚果伸长的开始，但不改变荚果伸长率。胚胎发育与荚果外长相匹配，与荚果实足年龄无关。这些结果表明，花后较长的日照通过缓解节点内不同等级荚之间的竞争来提高每节荚数。光周期效应对优势豆荚发育的影响，延迟了它们的伸长，从而推迟了它们的活跃生长，延长了开花时间，并使豆荚在通常的优势位置上结荚。
Long days during post-flowering postpone elongation and active growth of dominant pods within a node, which extends flowering and allows pod set at usually dominated positions. In soybean, long days during post-flowering increase seed number. This positive photoperiodic effect on seed number has been previously associated with increments in the amount of radiation accumulated during the crop cycle because long days extend the duration of the crop cycle. However, evidence of intra-nodal processes independent of the availability of assimilates suggests that photoperiodic effects at the node level might also contribute to pod set. This work aims to identify the main mechanisms responsible for the increase in pod number per node in response to long days; including the dynamics of flowering, pod development, growth and set at the node level. Long days increased pods per node on the main stems, by increasing pods on lateral racemes (usually dominated positions) at some main stem nodes. Long days lengthened the flowering period and thereby increased the number of opened flowers on lateral racemes. The flowering period was prolonged under long days because effective seed filling was delayed on primary racemes (dominant positions). Long days also delayed the development of flowers into pods with filling seeds, delaying the initiation of pod elongation without modifying pod elongation rate. The embryo development matched the external pod length irrespective of the pod’s chronological age. These results suggest that long days during post-flowering enhance pod number per node through a relief of the competition between pods of different hierarchy within the node. The photoperiodic effect on the development of dominant pods, delaying their elongation and therefore postponing their active growth, extends flowering and allows pod set at positions that are usually dominated.