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.

Author: Shakaktilar Taugal
Country: Cape Verde
Language: English (Spanish)
Genre: Life
Published (Last): 10 November 2017
Pages: 190
PDF File Size: 8.63 Mb
ePub File Size: 19.95 Mb
ISBN: 754-3-86916-358-2
Downloads: 2683
Price: Free* [*Free Regsitration Required]
Uploader: Nemuro

As the development of the antheridia is going on the surrounding vegetative tissue grows up and the antheridia become embedded in the dorsal furrow. For the Italian “comune”, see Riccia, Molise. You can help Wikipedia by expanding it. When this process of disintegration or decay reaches up ricia the place of dichotomy, the lobes of the thallus get separated.

Life Cycle of Riccia (With Diagram) | Hepaticopsida

A transverse division takes place in all the cells resulting in the production of a lower and an upper group of cells. Internally the thallus is differentiated into two regions, upper assimilatory region and the lower storage region.

The antheridial initial enlarges in size, becomes papillate and divides first by a transverse division to form an upper outer cell and a lower basal cell Fig.

In hygrophilous species species which need a large supply of moisture for their growth the scales are ephemeral i. We think you have liked this presentation.

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 air spaces, the cells of these filaments are rich in chloroplasts as these form the main photosynthetic tissue.

There is no special method of dispersal, Spores remain inside the thallus for one year or so and dispese after the death and decay of the calyptra and surrounding tissue. A mature archegonium is a flask shaped structure.

Many rhizoiu develop later on from the multicellular thallus and fix it on the soil Fig. The dorsal surface is light green or dark green body, each branch having a thick midrib. This article is about the plant Riccia. This mucilaginous mass consists of chemical substances such as soluble proteins and certain inorganic salts of potassium.

  BOSCH WFD 1160 PDF

Each androcyte has a prominent nucleus and a small extra-nuclear granule called blepharopiast. Simultaneously the nucleus also becomes crescent shaped, homogeneous and ultimately comes cyxle contact with the blepharoplast. They develop as prolongations of the lower epidermal cells. Due to prolonged dry summer or towards lire end of growing season the whole thallus in some species e.

The sporophyte of Riccia is the simplest amongst bryophytes.

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

Air pores occasionally break through the dorsal surface, giving the thallus a dimpled appearance. The cyycle are released in the surrounding water by the bursting of the antheridial wall and then these swim freely in the water. Rhizoids are cyc,e lacking in aquatic forms, but there are usually numerous unicellular rhizoids of two types on the ventral surface.

Scales contain anthocyanin pigment and when in water absorbs chlorophyll making it look green. The central cell divides Producing an egg or oosphere towards the base and a small ventral canal cell towards the upper side.

Some of the cells of the lower epidermis grow out and elongate forming the rhizoids, while certain cells divide and produce the single layered scales. The jacket initials by further anticlinal divisions only produce the single layered wall of the antheridium; while the androgonial initials by further transverse and vertical divisions produce a mass of androgonial cells which are enclosed by the single layered wall.

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

The thallus lfe dorsiventrally differentiated. Some cells of the lower epidermis ricciw to form the scales and both types of rhizoids. Cyclw organs develop in acropetal succession i. Riccia plants, like other liverworts, multiply vegetatively by the decay or death of the Older parts which results in the separation of younger branches, each of which grows into an independent plant.

When the antherozoids are produced the original walls of the androcytes become gelatinous thus producing a mucilaginous mass in which the antherozoids float freely. The canal of the neck contains a row of four neck canal cells and is closed at the tip by four lid cells. It lies near the periphery of the protoplast Fig.

The upper group of Peripheral cells divides by transverse divisions only producing the single layered wall of the neck in which the cells lifr arranged in six vertical rows. Riccia is a genus of liverworts in the order Marchantiales. The venter goes on increasing in size along with the developing sporogonium, and in this way the mature sporogoniurn remains enclosed in the double layered wall of venter. The necks of the mature lige protrude out above the general surface of the thallus, When the archegonia are mature the ventral canal cell and the neck canal cells disorganise forming mucilaginous mass which swells by absorbing water and comes out the neck by pushing apart the lid cells thus forming an opening for the entry of antherozoids.

  JK ROWLING UNA VACANTE IMPREVISTA PDF

Basal cell remains embedded rccia the tissue of thallus, undergoes only a little further development and forms the embedded portion of the antheridial stalk. The entire archegonium develops from the outer cell. The fertilized oosphere secretes a wall and becomes the oospore which develops into the sporogonium.

This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes. The mature lie are actually enclosed by the outer layer of the enlarged venter which is Often mistaken as the sporogonium wall.

Rhizoids are numerous, unicellular, elongated, tubular and hair-like and are found as simple rhizoids or tuberculate rhizoids.

Life Cycle of Riccia (With Diagram) | Hepaticopsida

Antheridium is present singly in an antheridial chamber. One of the more than species in this genus is the “slender riccia” Riccia fluitanswhich grows on damp soil or, less commonly, floating in ponds, [3] and is sometimes used in aquariums.

A wall is then secreted around ricvia oospore. California it is 9 Siler, Retrieved from ” https: It is more a method of perennation rather than multiplication. Riccia is a thallose liverwort in which the vegetative plant, which is a gametophyte, generally forms rosettes due to the ricci growth of the thallus lobes this crowded growth of the various lobes is due to the repeated dichotomies of the thallus The thallus lobes arc flat growing horizontally riccis the soil and each lobe has a small not that the apex where the growing point is situated.