Addition of longer wavelength absorbing chlorophylls into crops could increase their photosynthetic productivity by 26%

Abstract

Crop leaves absorb approximately 90% of visible photons (400 – 700 nm) but transmit or reflect most far-red (FR) photons (700 – 800 nm). However, some cyanobacteria use FR photons up to 800 nm by incorporating chlorophyll (Chl) d or/and f into their photosystems. Here, we use a 3D canopy model to evaluate whether introducing these pigments could improve photosynthetic performance of field grown soybean. We simulate photon absorption and CO2 assimilation show that the introduction of Chl d and f would significantly enhance photosynthesis, especially in the lower canopy, where visible light is depleted and FR light is abundant. When FR absorption is regulated by phytochrome-sensed FR/red (FR/R) photon ratio, the benefit is further increased, with canopy CO2 assimilation improving up to 26%, without increasing the risk of photodamage. These results show that introducing FR-absorbing Chls into crops could have great value in boosting productivity. Incorporation of the far-red light adaptation of cyanobacteria into crops has been suggested as a potential strategy to increase photosynthesis and yields, but the magnitude of this benefits has not been estimated. Here, via 3D canopy model of soybean, the authors show that it could increase CO2 assimilation up to 26%.

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