Figure 4.

RNA in situ hybridization of apices probed with cyclin D3a and cyclin D3b. Sections were probed with digoxigenin-labeled antisense RNA and viewed under bright-field optics which gives a purple-blue color. The cell walls, revealed by epifluorescence, appear light blue. A and B, Consecutive longitudinal sections of a vegetative meristem. A, Cyclin D3a transcripts are located mainly in the primordia (arrows) and the periphery of the meristem, with lower amounts in the young leaves (L), secondary meristems (*), and vascular tissues (v). B, Cyclin D3b is expressed throughout the central and peripheral regions of the meristem, in young leaves, secondary meristems, vascular tissues, and in trichomes (arrowheads). C and D, Transverse sections through the tip of an inflorescence apex and surrounding bracts probed with the cyclin D3a gene (C) and cyclin D3b (D). Arrowheads indicate trichomes.