Its been known for well over half a century that the energy conversion efficiency of incident photons to chemical energy by leaves is wavelength dependent. This is due to several processes that can be divided into two classes. First, the absorption of incident irradiance by a leaf is wavelength dependent due to the different absorption spectra of the different leaf pigments. Second, even on an absorbed light basis, different wavelengths have different quantum yields for CO2 ﬁxation or O2 evolution: Red light at 600 to 640 nm has the highest quantum yield, whereas blue and green light at 400 to 570 nm are considerably less efficient in driving photosynthesis.
The Wageningen University team’s paper (a downloadable pdf for now) published in the journal The Plant Cell shows by reducing the level of pigments which make no contribution to photosynthesis net plant productivity can be improved.
Their conclusion is based on research into the effectiveness of photosynthesis in various light conditions. The scientists discovered that leaf pigments not directly involved in photosynthesis ‘dissipate’ light by absorption rather than using it effectively.
Research into the effectiveness of photosynthesis in various light conditions has answered some of the most important questions. The research has shown that plants efficiently adapt their leaves to the light colors present where they grow. In this way they use the available light as effectively as possible. The research also demonstrated how specific combinations of various light colors result in more photosynthesis than the sum of the individual light colors. This insight is relevant, among other things, for minimizing energy consumption in the lighting of horticultural greenhouses.
The prime point is leaf pigments not directly involved in photosynthesis ‘dissipate’ useable light. While these non-photosynthetic pigments do absorb light, they do not use it for photosynthesis.
That discovery could lead to the development of plants that produce more food by reducing the amount of these non-photosynthetic pigments. That would first primarily apply to ‘protected’ cultivation, such as in greenhouses, as at least some of the non-photosynthetic pigments have a protective function, for instance against too much UV light or insect damage. These factors are less relevant in indoor cultivation than in open fields.
Considering the conditions across the planet from the tropics to the arctic, elevations, weather conditions and the other factors, tailoring plant genetics can be improved in yet another way.
The scientists have shown that understanding the different wavelengths of light available in a location applied to plant breeding can enhance quantum yields substantially. That would please those seeking to capture CO2 as well as produce more food and fuel.
The paper doesn’t offer numbers of the potential, yet its easy to grasp that humanity has moved plants from their native locations, worked on the hybridization, and optimized yields in major ways.
The team from Wageningen University shows us that the effort is far from finished and new understanding can push production even further.