Measuring the carbon conversion rate in field plants

It’s always instructive to go outside of the lab to see how plants are dealing with the fluctuating environment.

Dr. Dimitri Tolleter –CEA (France)

Gain4Crops aims at improving the sunflower biomass yield thanks to better efficiency of the carbon conversion via photosynthesis. But measuring such improvement in plants grown in the field is non-trivial, as multiple variables come into play in open-air: water and light availability, pathogens susceptibility, etc.

The team at CEA (France), led by Giovanni Finazzi, together with the team at the University of Padua (Italy), led by Prof. Tomas Morosinotto, has developed a non-invasive tool that allows evaluating the carbon conversion rate directly on plants in the field. “The measurement is quick and easy, and it exploits a small fluorescence signal that is naturally emitted during the photosynthesis” explains Prof. Morosinotto.

Indeed, the light absorbed by the chlorophyll in the plant is providing energy for the CO2 fixation or is dispersed when exceeds plant capacity to use it; but a small amount (1-2% usually) is also emitted back in form of fluorescence. This is the signal that the Gain4Crops team is recording on plant leaves and that indirectly gives information about the carbon conversion rate and enable us to estimate photosynthetic efficiency.

“We wanted a non-invasive, fast, and repeatable method for a sound and large data collection in the field,” says Prof. Morosinotto, “but as they are indirect measurements, the data need some aftermath”. In Gain4Crops the data analysis is led by the group of Prof. Benjamin Stich (Heinrich Heine University Düsseldorf – HHU) which uses the dataset generated by the other partners to extract information on the photosynthetic performance of different sunflower lines.

Measurement in the field on sunflowers cultivars grown by the partner CORTEVA in the south of France and supported by scientists from  HHU and CEA. Copyright @Dimitri Tolleter

The screening in the field has already started on sunflowers cultivars grown by the partner CORTEVA in the south of France and supported by scientists from  HHU and CEA, in particular Dimitri Tolleter who establish and validate the method there. “We had to design a protocol suitable for all the different stages of development of sunflowers, and easy to run for non-specialists users. For this, we have made a tutorial video to help users and it has been possible to phenotype for photosynthesis all the collection 2 times before the flowering and 3 times after. It’s always instructive to go outside of the lab to see how plants are dealing with the fluctuating environment.” says Dr. Tolleter. 

Once standardized, the protocol will be used throughout the project to collect more and more data also on improved plants and we are all very eager to get the first results.

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