Studies on microsporogenesis and mega sporogenesis in hybrids of tuberose (Polianthes tuberosa L.)

Abstract

Floral biology, histological and histochemical studies of the reproductive structures of tuberose cvs. Shringar and Suvasini were studied. In ‘Shringar’ and ‘Suvasini’ an average of 17.76 and 26.86 days were required for anthesis from the stage of visible initiation. The anther dehiscence started at 6 pm and 6.20 p.m in ‘Shringar’ and ‘Suvasini’ respectively. The maximum anther dehiscence was observed around 6.20 pm in ‘Shringar’ and ‘Suvasini’ it was 7.00 p.m. histological and histochemical changes in anthers of ‘Shringar’ revealed that, during early stages of development, sporogenous cells had intense polysaccharide, protein and rich polysaccharides, proteins and RNA. The tapetum started degenerating, thus assisting nutrition of developing microspores. This was followed by the development of pollen wall with exine and intine around the mature spores. In ‘Suvasini’, PMCs were intense in insoluble polysaccharides, RNA and rich protein content. In the anthers, tapetum is not well differentiated. In the pollen sac, pollen development is incomplete because of improper differentiation of tapetum. They were exposed to malnutrition as a consequence, the pollen development is not proper. At pollen grain stage they had rich polysaccharide, protein and intense RNA content. Histological and histochemical studies conducted on the developing ovule revealed that the ovule was anatropous, crassinucellate and bitegmic. The development stages viz., archesporium, megaspore mother cell, megaspore tetrad had low polysaccharides, intense proteins and RNA indicating a high rate of metabolic activity. The egg cell, synergids had rich polysaccharides proteins and RNA