Activity of rubisco and enzymes of sucrose synthesis and hydrolysis associated to latex productivity, in rubber tree clones [Hevea brasiliensis (Willd ex. Adr. de Juss.) Muell.-Arg] cultivated in Lavras, MG

Previous researches on rubber tree clone cultivation in Minas Gerais state have provided evidences for a possible association between photosynthetic variability and latex production. Nevertheless, knowledge about the CO 2 assimilation and carbon transport from leaves to bark, where the latex biosynthesis is higher, is still scarce. In all steps of these metabolisms, the reactions are regulated by some key enzymes. The aim of this work was to evaluate the Rubisco and the main enzymes of sucrose synthesis and hydrolysis activities in rubber tree plants from a clonal garden, identified as RRIM 600, GT 1, and FX 2261 clones, and their relationship to rubber productivity in the adult plants. The results suggested that the activities of Rubisco and invertases (acidic and neutral) are probably associated to the rubber productivity. This association was no clear in relation to sucrose-phosphate synthase (SPS) and sucrose synthase (SuSy), whose activity showed no difference among the clones. The sucrose hydrolysis in the bark was predominantly catalyzed by the acidic invertase. In smaller and equivalent proportions, sucrose hydrolysis was complemented by the SuSy and neutral invertase activity.