LIFE CYCLE OF MARSILEA PDF

Here are your notes on the life history of Marsilea! Characteristic features: This order includes a single family, Marsileaceae. The family includes the living. Etiology Thiaminases occur naturally in Marsilea spp., Cheilanthes spp., Figure A. Growth habit and reproductive structures of the sporophyte polypody fern. .. that centriolar duplication connected to the cell cycle is a secondary event. Download/Embed scientific diagram | – Life cycle of a Heterosporous Pteridophyte (eg: Marsilea) from publication: Diversity of Pteridophytes in Western Ghats.

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The tissues slowly swell up by absorbing water in natural conditions.

Young leaves show circinate vernation like ferns Fig. The structure of the outer wall of the sporocarp and gelatinous ring is the same as seen in transverse and longitudinal sections.

The latter divides to form an upper ventral canal cell and a basal egg. This cell is called as sporangial initial. Spore mother cells 2n undergo meiotic division to form 32 or 64 haploid spores n. It is smaller in size. There are three views which can be grouped under the following categories: They are heterosporous aquatic ferns.

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Each androcyte becomes a motile antherozoid by dissolution of the androcyte membrane. In certain species the raphe is not found, where the sporocarp is directly attached to the end of the peduncle, e. Habit and Habitat of Marsilea 2.

Marsilea: Habit, Structure and Reproduction

The primary cover cell further divides by two successive anticlinal divisions forming four quadrately arranged neck initials. Within the sporocarp there is a group of sori. The sporocarps may be oval or bean-shaped. Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top.

The morphological nature of the sporocarp of Marsilea has been controversial.

Marsilea: Habitat, External Features and Reproduction

The roots are adventitious, arising from the underside of the node of rhizome, either singly or in groups. The development of both the micro- and megasporangia is almost alike. In the inner region of the sporocarp only two chambers of sori are seen surrounded by separate indusia. The mucilaginous wall is a thick structure except in the papillate region. The leaves are borne alternately along the upper side of the rhizome at the nodes.

Marsilea: Habit, Structure and Reproduction

The species of Marsilea possess a rhizome which creeps on or just beneath the surface of the soil. The stele is amphiphloic solenostelic which occupies the centre of the rhizome. The air spaces are absent in xerophytic species e.

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The stele is amphiphloic siphonostele.

However, in some species e. The androcytes are metamorphosed into antherozoids. By breaking of the jacket cells and disintegration of male gametophytic tissue the antherozoids are liberated. In this region some of the tannin cells may be present here and there.

Each antherozoid is a cork screw shaped, spirally coiled multiflagellate, structure Fig. Each spore mother cell divides meiotically producing a tetrad of 4 haploid spores. Each spore shows a faintly developed triradiate ridge.

These lateral veins are given off alternately right and left. This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes. The megaspore is ellipsoidal and possesses a small projection at the anterior end. The stem is long, slender and marsiles rhizome of indefinite growth that grows on or just below the soil surface.

The microspore germinates just after its liberation.