LIFE CYCLE OF RICCIA PDF

Riccia is a genus of liverworts in the order Marchantiales. These plants are small and thallose, that is not differentiated into root, stem and leaf. Depending on. Riccia is a thallose liverwort in which the vegetative plant, which is a gametophyte, generally forms rosettes due to the crowded growth of the thallus lobes this. Riccia description with images for under graduate students. the gametophytic phase of the life cycle ends with the formation of zygote.

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The central cell divides into an upper primary neck canal cell and a lower venter cell.

Riccia – Wikipedia

In first division the chromosome number is reduced to half of the somatic number. For the Italian “comune”, see Riccia, Molise. The protoplasmic of the flow o the tip of this germ tube which becomes separated from rest of the by the formation of a septum.

In other projects Wikimedia Commons Wikispecies. Venter initial tier also divides by repeated transverse divisions to form a single layer of swollen venter.

Riccia Ms. Inderveena Sharma H.O.D. Botany Department

It consists of compactly arranged parenchymatous cells. The second division is at right angle to the first and results in the formation of four cells. A single-layered sterile jacket encloses the mass of androcytes which metamorphoses into antherozoids. Rhizoids and scales cyclle as anchors for the plant.

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The four nuclei migrate to the periphery of the spore mother cell and lie at equal distance from each other. It is more a method of perennation rather than multiplication.

Some cells of the lower epidermis extend to form the scales and both types of rhizoids. Upper epidermis is discontinuous and has non-green cells. Fycle cells of the amphithecium divide only by anticlinal division to form a single-layered sterile jacket or capsule wall.

These cells become softened and finally breakdown to release mass of antherozoids. The wall of the antheridium consists of a single layer of cells and encloses a mass of androcytes or antherozoid mother cells. The next division is also oife but it is at right angle to the first.

Riccia Ms. Inderveena Sharma H.O.D. Botany Department – ppt video online download

Each archegonium is a flask-shaped structure having a multi-cellular stalk. This bryophyte -related article is a stub. Ricccia zygote divides first by a transverse division to form two almost equal sized cells Llife. Rhizoids are numerous, unicellular, elongated, tubular and hair-like and are found as simple rhizoids or tuberculate rhizoids. The plant body of Riccia is gametophytic and gametophytes are fleshy, prostrate and dichotomously branched.

In Riccia crystallina the scales are inconspicuous and absent. Each spore mother cell produces the four spore the unsual method after the reduction division of its nucleus, spore mass is enclosed in the outer layer and not by the sporogonium wall which has disorganised. When the antherozoids are produced the original walls of the androcytes become gelatinous thus producing ricdia mucilaginous mass in which the antherozoids float freely.

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Field Museum of Natural History. It remains attached to the thallus by a short stalk. The Hepaticae and Anthocerotae of North America.

This gamete producesmale antherozoids and female oosphere gamete surrounding vegetative tissue. He considered these cells as the fore-runnes of elaters found in higher forms of Marchantiales. At the time of meiosis, the spore mother cells lie free within the cavity of sporogonium Fig.

Life cycle of riccia

It completes within a few minutes. Each branch of the thallus is linear, wedge-shaped or obcordate. A small part of the cytoplasm, which is not utilised in the formation of flagella may remain attached to the posterior ccle of antherozoid as a small vesicle.

The entire archegonium develops from the outer cell.