Sucrose and Metabolism Distribution Patterns in the Latices of Three Hevea brasiliensis Clones: Effects of Tapping and Stimulation on the Tree Trunk
Résumé
This study describes the sucrose balance between supply and demand in the bark of the rubber tree, along with concurrent latex metabolic activity. Experiments were designed using three H. brasiliensis clones (PB 235, RRIM 600 and GT (1)) in the same polyclonal plot at the Chachoengsao Rubber Research Centre (CRRC-DOA) in Thailand. Treatments were carried out on previously untapped trees (growth potential control), trees tapped without stimulation (1/2 S d/3 6 d/7 9 m/12, physiological control), and trees tapped with ethephon stimulation (1/2 S d/3 6 d/7 9 m/12 ET 2.5% 5/y and 12/y). Tapping had a marked effect on latex physiology in the whole trunk. Sucrose concentration was significantly reduced. The Latex Diagnosis Mapping (LDM) method was used to describe the shape and size of the latex regeneration area and of the metabolically active bark area. For the three clones, rubber production correlated with the estimated latex regeneration area. It took around 100 cm2 of latex regeneration area to regenerate 1 g of rubber. As it assesses the impact of any tapping system on whole trunk latex physiology, the LDM method was used to develop new tapping systems, such as systems involving ethylene gas stimulation, micro-tapping cut systems, and multi-tapping cut systems.