Ultrastructure of Non-Articulated Laticifers in Allamanda violacea

Ultrastructure studies on the differentiation of non-articulated branched laticifers in Allamanda violacea Gardn. were carried out. Growing laticifers show sequential changes. In the early stage, the laticifers possess electron dense cytoplasm, abundant mitochondria, ER, ribosomes, small vacuoles, nucleus and plastid with starch-grains. The ER dilates to form small vacuoles which coalesce at the later stages. A large central vacuole is formed in the mature laticifers due to the cellular autophagy of cytoplasm including the cell organelles. At this stage, the mitochondria possess a few cristae and plastids with plastoglobuli and small starch grains. Towards the end of differentiation the cytoplasm is restricted to a thin parietal layer along the cell wall, the remaining organelles being either reduced in number or degenerate. Plasmodesmata and primary pit fields are occasionally observed between the laticifer and the adjacent parenchyma cell.