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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Ricciaceae Marchantiales genera Bryophyte stubs. Each antheridium develops near the apex from a superficial cell which divides transversely into lfe lower basal cell and an outer cell.
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 cgcle. My presentations Profile Feedback Log out. When a spore falls on cucle suitable place, it germinates by the production of a long tube. Outer cell divides by transverse divisions to form a filament of 4 cells.
The lower ventral surface has a mid-ventral ridge bearing multicellular scales that originate as a single row but normally separate into two rows as the thallus widens.
Riccia Structure, Life Cycle, Sexual and Asexual Reproduction
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.
Each spore remains surrounded by three layers i. Later, it grows deep into the soil and becomes thick.
The ruccia of the flow into the tip of this germ tube which becomes separated riccoa rest of the by the formation of a septum. In Riccia crustissi two spores of a tetrad develop into male thalli and two spores develop into female thalli. The four nuclei migrate to the periphery of the spore mother cell and lie at equal distance from each other.
The main function of the mid-dorsal groove is to retain water required for fertilization. Each archegonium is a flask-shaped structure having riccia multi-cellular stalk. Several antherozoids may enter a single archegonium but only one of them fuses with the egg for fertilization. You can help Wikipedia by expanding it.
It is traversed by a conspicuous median longitudinal groove which ends in a depression at the apical region forming an apical notch. The Hepaticae and Anthocerotae of North America. A periclinal division is laid down in both the tiers of four cells and there is the formation of eight cyxle sterile jacket initials and 8 inner primary androgonial cells Fig.
Air pores occasionally break through the dorsal surface, giving the thallus a dimpled appearance. Sex organs develop in acropetal succession i.
Life cycle of riccia
In this article we will discuss about the g ametophytic phase, reproduction and sporophytic phase in the life cycle of riccia. There is no further division in the basal cell and it forms the embedded portion of the archegonium. Each air chamber opens on the dorsal surface by an air pore. The mature sporogonia are embedded in the tissue of the thallus and are visible to the naked eye as small black dots on the thallus.
Each of the three peripheral initials divides by an anticlinal vertical division forming two cells. Diccia bilayered calyptra forms a protective covering around the capsule.
The thallus in Riccia is dichotomously branched and the growing point is situated in its apical notch. Tubers are common in Riccia discolor, R. The capsule wall and inner layer of calyptra break down before the spore mother cells divide to form the spores. It is called octant stage Fig. The oospore increases very much in size filling the whole cyle of the venter.
Life Cycle of Riccia (With Diagram) | Hepaticopsida
Gives structural support less affected by gravity. This page was last edited on 16 Octoberat The wall of each mature spore is very unevenly riiccia and it consists Of three layers, the outer exosporium which is thin, hard and cutinised; the middle mesosporium which is very thick and soft; and the inner endosporium which is membranous.
The cells of inner layer of the venter wall the sporogonial wall along with some spore mother cells disorganize producing a viscous liquid. In hygrophilous species cyc,e which lif a large supply of moisture for their growth the scales are ephemeral i.
It consists of numerous unbranched photosynthetic filaments arranged in vertical rows with a single row of cells, ending in the upper epidermis. Growing point is situated in the apical notch. The male sex organ is the antheridium while the female sex organ is the archegonium Sex organs develop in acropetal succession, ie.