Methods and models

Gaseous exchanges

Gaseous exchanges

Gaseous exchanges measurement of young trees

Gaseous exchanges measurement system


By day time, the tree captures (CO2) from the air by PHOTOSYNTHESIS and throws back water (H2O) by TRANSPIRATION. The measurements of this GASEOUS EXCHANGES provide information on the plant functioning and status.

Measurement principle

Measurement principle


• By photosynthesis and transpiration, the air that gets out of the bag is poorer in carbonic gas CO2 but richer in water H2O.

• From the air flow Q that circulates, and the concentration difference D [CO2]and D[H2O] in and out the bag , we can calculate the gaseous exchanges :

Photosynthesis = Q*Δ[CO2]

Transpiration = Q*Δ[H2O]







Fax : 04 43 76 14 10

Logo piaf 2022

 Copyright © 2009, INRA, All rights reserved

Modification date : 01 December 2023 | Publication date : 14 February 2013 | Redactor : Dones - Frizot - Marcon