Fig. 1. (A) Semi-thin section through a <0.3 mm flower bud, stained with toluidine blue, showing one complete anther locule. Each locule contains a group of PMCs in meiotic interphase with prominent nucleoli, surrounded by four cell layers. It can be seen that the tapetal cells, adjacent to PMCs, are much smaller than the PMCs. (B-D) Spread and silver stained PMCs to show the typical progression of nuclear and nucleolar morphology through early meiosis. (B) Leptotene; chromosome axes are fully developed and the nucleolus is slightly off-centre. (C) Zygotene; chromosome axes beginning to synapse and showing some aggregation; the nucleolus is shifted to a peripheral location. (D) Pachytene; the chromosomes are fully synapsed; the nucleolus remains peripherally located. Bar, 5 µm (B,C,D); 10 µm (A).