Abstract: Changes in the patterns of microtubular distributions and organization in various stages of development of the embryo sac in rice ( Oryza sativa L. ) were different. In the megasporocyte, most microtubules were radially distributed but some were longitudinally oriented. Similar distributional patterns were seen in the dyad cells and the functional megaspore. Microtubules in the uni-nucleate embryo sac were mostly randomly distributed, although some radiated type was also present. The pattern of distribution of the microtubules in the two and four-nucleate embryo sac was quite similar and the microtubules were mainly of the pe.rinuclear type. Microtubules in the cells of the eight-nucleate embryo sac were more complex. In the egg cell, the microtubules were mostly randomly distributed whereas in the synergids they were pred6minantly in longitudinal alignment. Those in the central cell were transversely aligned. The antipodal mass had very few microtubules and few longitudinally aligned ones were present in the cytoplasm.

Key words: Oryza sativa, Embryo sac, Microtubules