The impact of global dimming on crop yields is determined by the source-sink imbalance of carbon during grain filling
The impact of global dimming on crop yields is determined by the source-sink imbalance of carbon during grain filling
复制标题
全球变暗对作物产量的影响是由籽粒灌浆过程中碳源库失衡决定的
DOI：
10.1111/gcb.15453
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发表时间：
2020-12-05
影响因子：
11.6
通讯作者：
Yin, Xinyou
中科院分区：
文献类型：
--
作者：
Shao, Liping;Liu, Zijuan;Yin, Xinyou
全球变暗减少了入射的全球辐射，但增加了散射辐射的比例，从而影响作物产量;然而，这种影响的潜在机制尚未被揭示。我们假设，作物源库的碳（C）或氮（N）在灌浆过程中的不平衡是一个关键因素的全球变暗对产量的影响。我们提出了一个实用的框架来评估C和N源-库关系，使用2013年至2016年在小麦和水稻田间试验中定期取样的生物量和N积累数据。研究结果表明，在全球变暗条件下，漫射辐射增加对C和N的贡献，缓解了全球辐射减少对源供给和汇生长的负面影响，但对C和N的源供给和汇生长仍有一定的抑制作用。在小麦中，碳源供应的减少超过碳汇需求，因此，作物调动更多的抽穗前碳储备，以应对调光。而水稻则匡威，这可能是由于水稻的辐射利用效率比小麦高，而水稻的库容量比小麦小。全球变暗对碳源供应和汇增长的影响大于对氮的影响。因此，在两种作物的产量更多地依赖于源库不平衡的碳比氮灌浆期间。我们揭示的源库关系，以及它们在小麦和水稻之间的差异和相似之处，为设计减轻全球变暗对作物生产力影响的策略提供了基础。
Global dimming reduces incident global radiation but increases the fraction of diffuse radiation, and thus affects crop yields; however, the underlying mechanisms of such an effect have not been revealed. We hypothesized that crop source-sink imbalance of either carbon (C) or nitrogen (N) during grain filling is a key factor underlying the effect of global dimming on yields. We presented a practical framework to assess both C and N source-sink relationships, using data of biomass and N accumulation from periodical sampling conducted in field experiments for wheat and rice from 2013 to 2016. We found a fertilization effect of the increased diffuse radiation fraction under global dimming, which alleviated the negative impact of decreased global radiation on source supply and sink growth, but the source supply and sink growth were still decreased by dimming, for both C and N. In wheat, the C source supply decreased more than the C sink demand, and as a result, crops remobilized more pre-heading C reserves, in response to dimming. However, these responses were converse in rice, which presumably stemmed from the more increment in radiation use efficiency and the more limited sink size in rice than wheat. The global dimming affected source supply and sink growth of C more significantly than that of N. Therefore, yields in both crops were dependent more on the source-sink imbalance of C than that of N during grain filling. Our revealed source-sink relationships, and their differences and similarities between wheat and rice, provide a basis for designing strategies to alleviate the impact of global dimming on crop productivity.