ANALYSIS OF POLY(A)-DT PROBES(RNA DISTRIBUTION DURING MAIZE SOMATIC EMBRYOGENESIS USING DIGOXIGENATED OLIGO)

The pattern of total transcription activity in terms of steady state l evels of poly(A)+ containing mRNA during callus initiation and somatic embryogenesis in a high (A188) and a low (A632) embryogenic line of m aize was analyzed using digoxigenin labelled oligo-dT probes. A gradua l increase and a preferential accumulation of label was observed in bo th lines, differing temporally up to 4 days in culture. In the A188 li ne of maize the callus gave rise to somatic embryos. The globular embr yos showed less label than the callus; this labelling was mostly prese nt in the basal part of the embryos. At a later stage upper embryogeni c and lower non-embryogenic layers were observed in the A188 callus, s howing conspicuous differences in the amount of label. In the late glo bular stage the poly(A)+ RNA signals were seen all over the embryo but at the junction of the suspensor and the callus tissue no label was o bserved.