Ultrastructure and oil secretion in Hiptage sericea Hook

Abstract

The oil secreting glands of Hiptage sericea Hook. consist of three regions: epithelial, sub-epithelial and sub-glandular. In early stages, the oil secreting cells are characterized by the presence of plastids with starch grains and electron translucent vesicles, mitochondria, rER, polysomes, small vacuoles, numerous lipid bodies and well-defined nucleus with nucleolus. Later, the accumulation of plastoglobuli and inclusion bodies occur in the matrix of the plastid. Tubular, smooth endoplasmic reticulum begins to appear in the cytoplasm. With the onset of secretion, the osmiophilic contents of plastids which appear as electron dense, round droplets move-into cytoplasm and often occur in the region of the plasmalemma invaginations. However, in matured glands the lipid bodies disappear from the cytoplasm. The size of the vacuoles increases and are filled with electron opaque substance. Similar substances are also found in the sub-cuticular spaces as well as outside the cuticle.