Sap flow and water status in adult rubber trees

Kunjet Summit, Thaler Philippe, Roupsard Olivier, Chantuma Arak, Siripornpakdeekul Pongpan, Kasemsap Poonpipope, Sangkhasila Kumut. 2007. Sap flow and water status in adult rubber trees. In : Natural rubber industry: R and D achievements and challenges : International Rubber Conference 2007, Siem Reap, Cambodia, 12-13 November 2007. CRRI, IRRDB. Phnom Penh : CRRI, 152-160. International Rubber Conference, Siem Reap, Cambodge, 12 Novembre 2007/13 Novembre 2007.

Résumé : Interactions of large scale plantations with variable environment is a major issue. This research studies the water relations in soil and plant in 13 years old rubber plantation, under natural condition of Chachoengsao Ruber Research Center (CRRC). In order to assess water balance of tree plantation on plot scale, it is necessary to partition total water flux measured by eddy-covariance. Therefore, accurate dynamic measurement of tree transpiration is required. Sapflow was measured by heat dissipation method (Granier, 1987) using 20 mm-long radial probes, connected to a data logger. The calibration of the probes was checked in laboratory with reference to the gravimetric method We adjusted the experiment devices to rubber .field conditions and evaluated the different sources of variability to design the appropriate monitoring process. The sapflow density decreased in the defoliation period and increased along the refoliation period during dry season, after that it was almost constant during vegetative growth period except during high rain events. Stand transpiration was quite similar to sapflow density. On a tree scale, seasonal and daily time of leaf water potential across the canopy and stomatal conductance were monitored together with climate data and soil moisture content. The soil moisture content was measured by gravimetric method and tensiometer. Plant water potential was measured with pressure chamber and stomata! conductance was detected by U-6400. A positive relationship was found between soil metric potential and daily stomatal conductance. However, daytime leaf water potential was unaffected by soil water content. In addition, leaf water potential depended on measurement height and daily stomatal conductance related to leaf water potential, sapflow density, and height.

Classification Agris : F60 - Physiologie et biochimie végétale

Auteurs et affiliations

• Kunjet Summit, RRIT (THA)
• Thaler Philippe, CIRAD-PERSYST-UPR Ecosystèmes de plantations (THA) ORCID: 0000-0002-9924-4309
• Roupsard Olivier, CIRAD-PERSYST-UPR Ecosystèmes de plantations (VUT) ORCID: 0000-0002-1319-142X
• Chantuma Arak, RRIT (THA)
• Siripornpakdeekul Pongpan, Kasetsart University (THA)
• Kasemsap Poonpipope, Kasetsart University (THA)
• Sangkhasila Kumut, Kasetsart University (THA)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/546584/)

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