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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Here’s how it works: Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top. Sex organs lie embedded in the mid dorsal section of the thallus between air spaces and filaments. The second division is at right angle to the first and results in the formation of four cells.

These octants divide further producing a group of about cells. These phases alternate with each other. The spores germination give rise to the gametophyte. This article is about the plant Riccia. A cycls part of the cytoplasm, which is not utilised in the formation of flagella may remain attached to the posterior end of antherozoid as a small vesicle.

Life cycle of riccia

The adventitious branches develop from the ventral surface of the thallus in species like Riccia fluitans. The canal of the neck contains a row of four neck canal cells and is closed at the tip by four lid cells.

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Some hairy epidermal outgrowths are also seen in Riccia melanospora, though rarely Fig. The fusion of the nuclei of male and female gamete results in the formation of diploid ricxia or oospore.

In the majority of species the assimilatory region is formed of vertical rows of cells which are about six to eight cells in height and are separated by large riccis spaces, the cells of these filaments are rich in chloroplasts as these form the main photosynthetic tissue. The mature spores are actually enclosed by the outer layer of the enlarged venter which is Often mistaken as the sporogonium wall.

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Sex organs develop in acropetal succession i. Chapter 29 Reading Quiz About how many species of plants inhabit earth today?

The cell walls form the semifluid content of the antheridium during the metamoiphosis. The plant body of Riccia is gametophytic and gametophytes are fleshy, prostrate and dichotomously branched. Some cells of the lower epidermis extend to form the scales and both types of rhizoids.

Life Cycle of Riccia (With Diagram) | Hepaticopsida

The thallus is dorsiventrally differentiated. The capsule wall and inner layer of calyptra break down before the spore mother cells divide to form the spores. Spore mother cells undergo meiosis. In this article we will discuss about the g ametophytic phase, reproduction and sporophytic phase in the life cycle of riccia. In this way the primary axial cell gets rccia by six cells Fig.

Antheridium is present singly in an antheridial chamber. Simultaneously the nucleus also becomes crescent shaped, homogeneous and ultimately comes in contact with the blepharoplast.

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Life Cycle of Riccia (With Diagram) | Hepaticopsida

In smooth-walled rhizoids both the inner and outer wall layers are fully stretched while in tuberculated rhizoids the inner wall layer modifies into peg-like or plate-like in growth which projects into the cell lumen Fig.

Riccua fertilized oosphere secretes a wall and becomes the oospore which develops into the sporogonium. They develop as prolongations of the lower epidermal cells.

In Riccia crustissi two spores of a tetrad develop into male thalli and two spores develop into female thalli.

After meiosis the mass of spores lies free in the outer layer of calyptra and mature sporogonium has no diploid structure. Liff axial cell cuts of a small cover cell at the tip.

This represents octant stage Fig. The of the mature capsule consists of a single layer of cells surrounding a mass of spore mother cells.

Riccia – Wikipedia

The storage region is formed of compactly arranged parenchymatous cells which are either colourless or contain only few chloroplasts, but these cells are rich in starch grains. It cuts a number of cells on its left and right side to form the multicellular thallus Fig. Each spore remains surrounded by three layers i.

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