Estudo sôbre a distribuição do S35 em cafeeiro (Coffea arabica L, Bourboon)

Abstract

This work was carried out in order to study the distribution of S35 in higher plants, represented in this case by coffee (Coffea arabica L., var. Bourbon). Young coffee plants 6 months old were grown in the greenhouse in nutrient solution and received: a) solution of S35 brushed inthe lower surfaces of selected leaves; b) solution of S35 in nutrient solution in order to be absorbed by roots. In (a) procedure the plants were divided in their parts: roots, stms, young leaves and old leaves, and the leaves were divided in petiole, blade and midrib and veins. In (b) procedure, we had three groups of plants for: 1) studies of translocation, like in (a); 2) radioautography; 3) study of leaching of S35 from leaves. On the other hand, in the field experiment, 4 years old coffee plants received S35 that has been sprayed directly on the leaves. The analysis showed a short translocation of S35 in the coffee plant and: 1) the S35 translocation is mainly from old leaves to newer leaves and very few to the stem and roots; 2) from roots the S35 gets to the other parts of the plant to the old leaves; 3) the autoradiografhy of the coffee plant showed the same results obtained with the analysis of radioactivity in the various parts of the plant; 4) S35 is leached from leaves by rainfall.