A Cytochemical Study of Ovule Development in Dipcadi montanum Dalz

Abstract

The megasporogenesis and the female gametophyte development in the ovule of Dipcadi montanum Dalz. were studied using the cytochemical staining techniques for polysaccharides, DNA, RNA and proteins. The insoluble polysaccharides are at very low level in the archesporium, MMC, dyads, tetrads and functional megaspore stages while RNA and proteins are at a higher level of concentration in all of them. The degenerating spores have an intense concentration of RNA and proteins in them. The cytoplasm of young embryo sac and the central cell of mature embryo sac has a low concentration of polysaccharides, RNA and proteins. The enlarged, haploid nuclei in the dyad cells, tetrad of spores, functional spore and young embryo sac have very faint DNA stainability.
In the mature embryo sac, the egg cell has a low concentration of cytoplasmic polysaccharides and RNA while proteins are at a very high level; the synergids have densely PAS positive filiform apparatus and rich concentration of cytoplasmic proteins while they have very less RNA content; the antipodal cells have enlarged nuclei with rich DNA staining and their cytoplasm has rich polysaccharides and proteins. The enlarged fusion nucleus or the free polar nuclei have less DNA in them.
The cells of the hypostase and those of the integuments at the growing tips have rich RNA and proteins.