%0 Journal Article
%A V. V. Anand
%T A Comparative Account of the Gametophytes of Pollen Haploids and Parental Plants of Nicotiana tabacum L.
%D 2001
%J Taiwania
%V 46
%N 3
%P 204-216
%U https://taiwania.ntu.edu.tw/abstract/291
%X Pollen haploids from Nicotiana tabacum L. cv FCV Special were raised by culturing their anthers on MS medium supplemented with .001mg BAP. The haploid plants were grown to adult stage. They flowered profusely but did not produce seeds. A comparison is made between the haploids and their normal parental diploids with reference to the ontogeny and organization of microsporangium, male gametophyte, megasporangium and female gametophyte. The development of microsporangium and male gametophyte in haploids revealed several interesting features. The events pertaining to the development of sporophytic features of microsporangia in haploids were more or less recapitulative of those in normal parental plants. Meiosis in microsporocytes is highly irregular and commences in a few microsporocytes, precociously, at the sporogenous tissue stage itself. Cytomixis, chromosomal disarray and occurrence of laggards are common. Very few 'tetrads' of irregular configurations are organized. Despite anomalous gametogenesis and production of a few microspores, consistently sterile, the anthers dehisced normally as observed in the parental plants. Megasporogenesis and female gametophyte development were highly irregular and unpatternized in haploids. The ovaries were distinctly smaller and possessed fewer ovules than in the diploids. Many ovules degenerated early in their ontogeny. A few that did not, exhibited merely a semblance of embryo sac development and organization, far from the normal patternized events seen in the normal diploids. A bisporic mode of embryo sac ontogeny is prevalent in the haploid ovules. The female gametophytes exhibited precocious organization but never conformed to a uniform pattern. Very few embryo sacs organized into an 8-nucleate Polygonum type of embryo sac. A few apomictic embryoids were noticed in the haploid ovules.
%M doi:10.6165/tai.2001.46(3).204