Know more

About cookies

What is a "cookie"?

A "cookie" is a piece of information, usually small and identified by a name, which may be sent to your browser by a website you are visiting. Your web browser will store it for a period of time, and send it back to the web server each time you log on again.

Different types of cookies are placed on the sites:

  • Cookies strictly necessary for the proper functioning of the site
  • Cookies deposited by third party sites to improve the interactivity of the site, to collect statistics

Learn more about cookies and how they work

The different types of cookies used on this site

Cookies strictly necessary for the site to function

These cookies allow the main services of the site to function optimally. You can technically block them using your browser settings but your experience on the site may be degraded.

Furthermore, you have the possibility of opposing the use of audience measurement tracers strictly necessary for the functioning and current administration of the website in the cookie management window accessible via the link located in the footer of the site.

Technical cookies

Name of the cookie


Shelf life

CAS and PHP session cookies

Login credentials, session security



Saving your cookie consent choices

12 months

Audience measurement cookies (AT Internet)

Name of the cookie


Shelf life


Trace the visitor's route in order to establish visit statistics.

13 months


Store the anonymous ID of the visitor who starts the first time he visits the site

13 months


Identify the numbers (unique identifiers of a site) seen by the visitor and store the visitor's identifiers.

13 months

About the AT Internet audience measurement tool :

AT Internet's audience measurement tool Analytics is deployed on this site in order to obtain information on visitors' navigation and to improve its use.

The French data protection authority (CNIL) has granted an exemption to AT Internet's Web Analytics cookie. This tool is thus exempt from the collection of the Internet user's consent with regard to the deposit of analytics cookies. However, you can refuse the deposit of these cookies via the cookie management panel.

Good to know:

  • The data collected are not cross-checked with other processing operations
  • The deposited cookie is only used to produce anonymous statistics
  • The cookie does not allow the user's navigation on other sites to be tracked.

Third party cookies to improve the interactivity of the site

This site relies on certain services provided by third parties which allow :

  • to offer interactive content;
  • improve usability and facilitate the sharing of content on social networks;
  • view videos and animated presentations directly on our website;
  • protect form entries from robots;
  • monitor the performance of the site.

These third parties will collect and use your browsing data for their own purposes.

How to accept or reject cookies

When you start browsing an eZpublish site, the appearance of the "cookies" banner allows you to accept or refuse all the cookies we use. This banner will be displayed as long as you have not made a choice, even if you are browsing on another page of the site.

You can change your choices at any time by clicking on the "Cookie Management" link.

You can manage these cookies in your browser. Here are the procedures to follow: Firefox; Chrome; Explorer; Safari; Opera

For more information about the cookies we use, you can contact INRAE's Data Protection Officer by email at or by post at :


24, chemin de Borde Rouge -Auzeville - CS52627 31326 Castanet Tolosan cedex - France

Last update: May 2021

Menu Logo Principal Institut Agro Montpellier LEPSE membre de University of Montpellier Labex AGRO Institut Carnot DigitAg

Home page

Pressure chambers

Measuring the water potential of a plant

The LEPSE is not in a position to lend or rent pressure rooms. Thank you for your understanding

The pressure chamber (or Scholander bomb) is a piece of equipment that allows the precise measurement of the water potential of a plant, by extracting the sap. It is used, for example, in viticulture to assess the water status of the vine. At LEPSE, it is mainly used to assess the water status of grapevine, wheat and sometimes Arabidopsis thaliana.


Banc d'étalonnage photo 1 @ SB_2021


A pressure chamber consists of a cylinder that encloses a member (leaf, rod, etc.) whose end protrudes from the cover. The cover of the chamber includes a seal (a plug between two brass washers). This seal, tightened around the end, allows the member to be sealed in the cylinder. The pressure chamber is connected to a source of compressed nitrogen. Two valves control the flow of gas into the closed chamber. The pressure gauge indicates the evolution of the pressure in the chamber. When the gas pressure in the chamber balances the sap pressure in the organ, a meniscus appears on the end of the organ protruding from the sap cover: equilibrium is said to have been reached. The pressure corresponds to the water potential.


Measuring the basic or minimum water potential. The leaf water potential (Y) reflects the state of water binding within the plant tissue.


  • Measurement of the basic leaf potential (late night)
  • Measurement of minimum leaf potential (during the day, solar noon in the field)
  • Measurement of stem potential (leaf wrapped in plastic and aluminium foil)
  • Sap sampling (ABA determination)

The method is destructive and not automated.

Pressure chambers at LEPSE

Our fleet consists of pressure chambers and compressed nitrogen cylinders. The chambers are calibrated every year, and since March 2021, with a calibration bench designed by Stéphane Berthézène and installed in our unit by Stéphane Berthézène and Anthony Rosello (photos 1 and 2).

Equipment manager : Aurélien Ausset
Calibration bench metrology manager : Stéphane Berthézène


Banc d'étalonnage photo 2 @ SB_2021