Discovery of in situ apogamous, abortive embryos inside the megaspores of Isoetes L.

摘要

The present investigation is based on the study of four species of Isoetes found in the state of Rajasthan. Thin serial sections have shown the presence of in situ apogamous and abortive embryos inside the megaspores. Normally a megaspore germinates on the ground and produces many archegonia on the exposed portion of the megagametophyte and the embryo is lodged inside the archegonium. But in the present study embryos are seen originating directly from the free floating nucleated cells of the gametophytes inside the megaspores. This is the first report of such an embryogeny in the taxon Isoetes.