VariaÃÃo sazonal da atividade da rubisco e das enzimas de sÃntese e hidrÃlise da sacarose em plantas de seringueira [Hevea brasiliensis (Willd ex. Adr de Juss.) Muell.-Arg], em Lavras/MG / Seasonal variation of Rubisco and sucrose synthesis and hydrolisys enzymes activities in rubber trees [Hevea brasiliensis (Willd ex. Adr. de Juss.) Muell.-Arg], in Lavras, MG.

Paulo AraquÃm Ramos Cairo

The growth of rubber tree cultivation in Brazil has happened because of growing of natural rubber market. With aim to escape of âSouth American leaf blightâ â a common disease in amazonian region â the rubber tree expansion has privileged no traditional regions in Brazil. In Minas Gerais, where rubber tree cultivation is still incipient, new researches about some physiological aspects can promote expansion of the cultivation. Late researches about rubber tree clones in Lavras â MG have investigated a possible association between photosynthetic variability and rubber productivity. Nevertheless, there is still no information about some metabolic aspects that are involved with latex biosynthesis, like CO2 assimilation, carbon translocation from source tissues to attend carbohydrate requirement of sinks, where the latex production is highest. In all of these processes, the metabolic reactions are directly regulated by some key enzymes. The aim of this work was to evaluate, in rubber tree plants from a clonal garden, identified as RRIM 600 and GT 1 clones, the seasonal changes of environmental factors and their possible effects on the Rubisco activity and the most important enzymes of sucrose synthesis and hydrolisys metabolism. The work had still aim to observe, during the hot and raining season, if it is possible this enzymatic activity, including in FX 2261 clone, have association with the rubber productivity of adult plants, identified as the same clones from clonal garden. The results showed that the seasonal changes in environment can induce oscillations in Rubisco, SPS, invertases and SuSy enzyme activities, in rubber trees cultivated in Lavras-MG. The enzyme activities, in general, in the RRIM 600 and GT 1 clones, were higher in the hot and raining season than in the cold and drought season. Based on the experimental conditions, one can conclude that the temperature seems have been the most influent environmental factor on the enzymatic activity. In relation to the majority of enzymes evaluated in plants from clonal garden, the results suggested a possible association between Rubisco, invertases and SuSy activities and the latex productivity of adult plants.

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