Morphology of Marsilea Systematic position Kingdom : Plantae - CEC

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Fig. 11 Diagrams showing developmental stages of micro- and megasporangia of Marsilea sp. Development of sporangia: Since Marsilea is a heterosporous fern, megasporangia (macrosporangia) produce megaspores and the microsporangia produce microspores. The sporangia develop in a basipetalous manner on the receptacle. The megasporangia develop first at the top of the receptacle and are, therefore, older, while the microsporangia develop later along the sides of the receptacle. The development of microsporangium, as well as of megasporangium is almost similar. The sporangial initial divides transversely, forming an outer and an inner cell. The entire sporangium develops from the outer cell, the inner cell taking no part in
its development. The outer cell of sporangium, which is destined to form spore mother cell, undergoes repeated divisions. Each spore mother cell undergoes reduction division and forms four haploid spores. In megasporangia, all but one spore degenerates to form a nutritive liquid, which grows in size at the expense of others, forming a single large functional megaspore (Fig. 12). In microsporangia, almost all the spores in a microsporangium are functional. They are smaller in size. Fig. 12 Marsilea sp.: mature megaspore within the megasporangium, showing very thick and well-differentiated wall. Dehiscence of sporocarp: There is no special mechanism for the liberation of sporangia from the sporocarp. They are set free only when the wall of the sporocarp splits open. As the sporocarp breaks at one point due to absorption of water, the sori come out along the gelatinous ring of sporocarp (Fig. 13). These sori function as mother cells of the gematophytic generation.
Page 1 and 2: Morphology of Marsilea Marsilea, co
Page 3 and 4: Root: The primary root formed on th
Page 5 and 6: Anatomy of Marsilea Rhizome (Stem)
Page 7 and 8: Leaflet Fig. 5 Marsilea:Transverse
Page 9 and 10: Vascular bundle lies within the end
Page 11 and 12: Fig. 8 Marsilea: different modes of
Page 13: cell for the second sporocarp. This
Page 17 and 18: gametophyte, while prothallial cell
Page 19: produced within the fruit body, the

Morphology of Marsilea Systematic position Kingdom : Plantae - CEC

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