Cytologics aspects of the differentiation of coffee tissues in culture

Abstract

Callus was established from leaves and shoots of Coffea arabica L. on nutrient medium with various levels of auxins and kinetin. Morphogenesis is controllable in such callus tissues by manipulation of the growth factor levels in the media. The study shows that callus culture obtained from leaves are in different states of differentiation, i.e., although the calluses were similar in appearence, their morphogenetical potential was different. The cells in culture show a great range of growth and form, and that form and behaviour of such cells do not correspond with recognized cell types in normal plant tissues or meristems. Proembryoids and vascularization (Fig. 1), giant cells (Fig. 4) and other patterns of cell differentiation (Figs. 2 and 3) were observed. The initiation of an organized system is probably dependent upon some rather specific environmental conditions. The extent to which certain specific types of differentiation are concomitant would seem to be a reflection of the extent to which common factors are involved. Thus, in this type of change, casuality of the nuclear change to the other changes would be unlikely.