THE MORPHO-EMBRYOLOGICAL STUDIES OF RHYNCHELYTRUM REPENS (WILLD) C. E. HUBBARD

Dr. M. Saquib & Dr. M. Inamuddin

The present investigation presents the morphological and embryological studies of Rhynchelytrum repens (willd) C. E. Hubbard. The development of anther walls are found to be Monocotyledonous type. The tapetal cells are substantially large, glandular and uninucleate. The middle layer is ephemeral and their cells are smaller in size. It is sandwiched between endothecial layer and tapetal layer. The endothecial cells are large and develop fibrous thickenings. The microscope mother cell undergoes tetrad. The tetrad separates and gives rise to four pollen grains. Some times, the pollen grains remain intact from the common wall of the microspore tetrad and do not separate even up to maturity of the anther. Occasionally anthers show degenerating pollen grains before dehiscence. Formation of Ubisch’s bodies has also been observed. The pollen grains shed at three celled stage. The exine is thick while intine is thin.
The ovule is anatropous, bitegmic and crassinucleate. The female archesporial cell becomes large with dense cytoplasm. It directly functions as megaspore mother cell and undergoes two meiotic divisions to produce a linear megaspore tetrad. The micropylar three cells degenerate and chalzal one becomes functional. The chalazal functional megaspore undergoes three mitotic divisions without wall formation and produces 8-nucleate embryosac. Such 8-nucleate embryosac organizes into 8-nuclrate Polygonium type of embryosac. It is interesting to note that somatic cells of the ovule undergo nuclear divisions and give rise to facultative- apomictic embryosac.