Integrative Crop Ecophysiology Group, Plant Physiology Section, Faculty of Biology, University of Barcelona, Barcelona, and AGROTECNIO Center, Lleida, Spain.
Plant Ecophysiology and Metabolism Group, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
J Exp Bot. 2021 May 18;72(11):3936-3955. doi: 10.1093/jxb/erab097.
Increasing the speed of breeding to enhance crop productivity and adaptation to abiotic stresses is urgently needed. The perception that a second Green Revolution should be implemented is widely established within the scientific community and among stakeholders. In recent decades, different alternatives have been proposed for increasing crop yield through manipulation of leaf photosynthetic efficiency. However, none of these has delivered practical or relevant outputs. Indeed, the actual increases in photosynthetic rates are not expected to translate into yield increases beyond 10-15%. Furthermore, instantaneous rates of leaf photosynthesis are not necessarily the reference target for research. Yield is the result of canopy photosynthesis, understood as the contribution of laminar and non-laminar organs over time, within which concepts such as canopy architecture, stay-green, or non-laminar photosynthesis need to be taken into account. Moreover, retrospective studies show that photosynthetic improvements have been more common at the canopy level. Nevertheless, it is crucial to place canopy photosynthesis in the context of whole-plant functioning, which includes sink-source balance and transport of photoassimilates, and the availability and uptake of nutrients, such as nitrogen in particular. Overcoming this challenge will only be feasible if a multiscale crop focus combined with a multidisciplinary scientific approach is adopted.
为了提高作物的生产力和适应非生物胁迫，加快繁殖速度迫在眉睫。科学界和利益相关者普遍认为，应该实施第二次绿色革命。近几十年来，人们提出了许多通过操纵叶片光合作用效率来提高作物产量的替代方案。然而，这些方案都没有带来实际或相关的产出。事实上，光合作用速率的实际增加预计不会超过 10-15%，从而转化为产量的增加。此外，叶片光合作用的瞬时速率不一定是研究的参考目标。产量是冠层光合作用的结果，理解为一段时间内层状和非层状器官的贡献，其中需要考虑冠层结构、持绿或非层状光合作用等概念。此外，回顾性研究表明，在冠层水平上，光合改良更为常见。然而，至关重要的是要将冠层光合作用置于整株植物功能的背景下，其中包括源库平衡和光合同化物的运输，以及氮等营养素的可用性和吸收。只有采用多尺度作物重点和多学科科学方法相结合的方式，才能克服这一挑战。
