News

By Natalia Bateman and Ross Deans, CoETP,  September 28, 2020

A team of scientists has created a model that is providing a clearer insight into the way plants use carbon to grow. This model looks at how carbon is invested inside a leaf to maximise carbon profit from an economical point of view, a bit like the stock exchange but where the funds are carbon-based molecules.

Plants have the incredible ability to transform carbon from the atmosphere to build more of themselves through the process of photosynthesis. Mathematical models allow scientists to understand this complex transformation and predict the effects of the many factors involved in the coordinated dance of plant growth.

In a recent published paper in the journal Nature Plants, a team of scientists has created a model that is providing a clearer insight into the way plants use carbon to grow. The team created a model that looks at how carbon is invested inside a leaf to maximise carbon profit from an economical point of view, a bit like the stock exchange but where the funds are carbon-based molecules.

“We wanted to understand how plants go through the economic challenge of using the carbon they have available in the most efficient way.  We know that for a plant to do this, it needs to coordinate very tightly both carbon costs in leaf gas exchange and water relations and gains through photosynthesis, which are linked through plant physiology,” says lead researcher Dr Ross Deans, from the ARC Centre of Excellence for Translational Photosynthesis, located at ANU.

“We created an analytical model that can predict the optimal conditions in terms of carbon gains and losses for a plant in the long term. We used a method called optimisation that models how the plant negotiates carbon costs and gains, so it ends with the best option under each specific circumstance”.

Other models have looked at this problem before, but they focused mainly on water availability.

“This model is unique in that it takes into account factors that haven’t been considered before, such as the carbon costs of building and maintaining the pores of the leaf, leaf hydraulics and osmotic pressure,” says Professor Graham Farquhar, co-author of the paper.

The idea is that the plant wants to carefully invest carbon in a way that maximises its net carbon profit, but to do this often requires it to coordinate many factors simultaneously. For example, a plant could photosynthesise more if it invests in more pores on the leaf (or stomata) but unless it also invests in water supply infrastructure, then the pores will be more closed and it will not take full advantage of the investment. However, building both also has an associated cost.

Understanding this coordination is important, because it highlights the fact that by making a plant grow better by improving one trait affects other factors, so you need to balance the costs of multiple factors in order to get the best allocation of resources.

“Our model also provides predictions of plant adaptations to drought. Using it, we can now estimate the relative cost of key leaf functional traits, and work out which processes are energetically more expensive,” says Dr Deans.

Access the Nature Plants paper here: https://www.nature.com/articles/s41477-020-00760-6

This research was originally published in September 2020 here:

Deans, R.M., Brodribb, T.J., Busch, F.A. et al. Optimization can provide the fundamental link between leaf photosynthesis, gas exchange and water relations. Nat. Plants 6, 1116–1125 (2020). https://doi.org/10.1038/s41477-020-00760-6 Read paper

For an interview please contact:

Dr Ross Deans e-mail: rdeans@ucdavis.edu Twitter: @RossMDeans

Professor Graham Farquhar e-mail: graham.farquhar@anu.edu.au Twitter: @GrahamDfarquhar

Media Assistance:

Natalia Bateman, Communications officer, ARC Centre of Excellence for Translational Photosynthesis. e-mail: natalia.bateman@anu.edu.au m. +61 0401 083 380 Twitter: @leaf2field