How much can enhancing photosynthesis improve yield?

The prediction tool can quantify the yield gains associated with manipulating photosynthesis in realistic crop environments, according to Dr Alex Wu, from the ARC Centre of Excellence for Translational Photosynthesis (CoETP) and The University of Queensland (UQ). This is reported by ScienceDaily.

Studies have shown that photosynthesis, the process with which plants convert sunlight, carbon dioxide and water into food, can be engineered to be more efficient.

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The modelling tool has the capacity to link across biological scales from biochemistry in the leaf to the whole field crop over a growing season, by integrating photosynthesis and crop models. – Photo: AFP

New ways to improve yields

“Until now, it has been difficult to assess the impacts of these manipulations on crop yield. This prediction tool will help us to find new ways to improve the yields of food crops around the world, ” said Dr Wu.

The modelling tool has the capacity to link across biological scales from biochemistry in the leaf to the whole field crop over a growing season, by integrating photosynthesis and crop models.

“It is a powerful tool to assess and guide photosynthetic manipulations and unravel effects that confound the relationship between photosynthetic efficiency and crop performance, ” Dr Wu said.

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“We know that it is not as simple as saying that improving photosynthesis will increase yield. The answer depends on the situation,” said Researcher at the Australian National University (ANU) and co-author of the study Professor Susanne von Caemmerer.

More photosynthesis can actually decrease yield

“For example, we found that in crops like sorghum, more photosynthesis can actually decrease yield in water-limited cropping situations. The modelling predicts that we can manage this yield penalty if we can also maintain a stable rate of carbon dioxide entering, or water vapour exiting, the pores of a leaf.”

3 main photosynthesis manipulation targets

The team investigated 3 main photosynthesis manipulation targets: enhancing the activity of the main photosynthetic enzyme, Rubisco; improving the capacity of the leaves to transport electrons; and improving the flow of carbon dioxide (CO2) through the internal layers of the leaf.

“This study permits us to quantify the consequences on crop yield for these 3 targets and their combinations for wheat and sorghum crops for irrigated or dryland cropping environments,” said Dr Wu.

12 per cent increase

The team found crop yield changes ranged from a reduction of one per cent to a 12 per cent increase, depending on the combination of photosynthetic targets, the crop and environmental conditions such as water availability.