ABSTRACT
Being a nonphotosynthetic tissue, the productivity of the sink will depend on photosynthate supply by the source leaves, and on long-distance translocation, allocation, and efficiency of utilization of mobile sugars for laticiferous tissue metabolism and rubber formation. Most of the knowledge on sugar metabolism of laticifers comes from studies on the latex collected by tapping, its cytosolic fraction separated by centrifugation, and on enzyme preparations isolated from them. A reduction of the rate of sucrose utilization, both according to sugar decrease and CO2 production from C-sucrose, was also observed. An important feature of bark treatment with ethephon is a considerable extension of the area activated in sucrose catabolism, as indicated by an increase in pH and invertase activity in successive latex fractions taken after opening of the tapping cut. Most information on sucrose allocation to latex vessels is based on simple determinations of sucrose content in the latex reflecting the balance between sucrose entry and consumption.
