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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Riccia Ms. Inderveena Sharma H.O.D. Botany Department
A periclinal division is laid down in both the tiers of four cells and there is the formation of eight outer sterile jacket initials and 8 inner primary androgonial cells Fig. California it is 9 Siler, My presentations Profile Feedback Log out.
The second division is at right angle to the first and results in the formation of four cells. Antheridium is present singly in an antheridial chamber.
The newly formed young gametophyte remains enclosed with in the old gametophyte Fig. 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. Rhizoids and scales serve as anchors for the plant.
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Nucleus of each spore mother cell divides by two successive divisions to form 4 haploid nuclei. This is a question and answer forum for cyce, teachers and general visitors for exchanging articles, answers and notes.
Chinese Company introduces new low price Chinese electric car in Pakistan. In the monoecious species the antheridia are generally produced earlier than the archegonia. Each androcyte thus metamorphosis into an ccle Fig. The main function of rhizoids is to anchor the thallus on the substratum and to absorb water and mineral nutrients from the soil.
The process of metamorphosis of androcyte mother cells into antherozoids is called spermatogenesis.
Life Cycle of Riccia (With Diagram) | Hepaticopsida
Later, it grows deep into the soil and becomes thick. A mature antheridium has a short stalk and oval shaped body with a flat base and conical apex Fig. The necks of the mature archegonia 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.
The scales are multicellular and hyaline glassy in appearance, or violet due to the pigment anthocyanin. One flagellum serves for propulsion and the other for rotation and for changes in direction Fig. It is made of somewhat vertical rows of un-branched photosynthetic filaments.
Both the male antheridia and female archegonia reproductive organs are produced in acropetalous order on the dorsal side of the thallus in the median furrow.
Riccia is a genus of liverworts in the order Marchantiales. The mature sporogonium in Riccia is of very simple structure. The lobes in Riccia fluitanswhich is an aquatic species, are narrow and ribbon-like having repeated dichotomous branches which do not form any rosetts, Numerous unicellular rhizoids are found attached to the ventral side of the thallus, these rhizoids are generally crowded in the middle part of the thallus and are of two types i.
Riccia Structure, Life Cycle, Sexual and Asexual Reproduction
riccia It lies near the periphery of the protoplast Fig. Neck initials tier divides by repeated transverse divisions to form a tube-like neck. Due to prolonged dry summer or towards the end of growing season the whole thallus in some species e.
They develop as prolongations of the lower epidermal cells. A vertical division takes place in each peripheral cell resulting in the production of six jacket initials.
Registration Forgot your password? The vegetative plant or thallus in Riccia, is a gametophyte, whose cells are haploid. Spores are very small 0. The main function of the mid-dorsal groove is to retain water required for fertilization.
Some hairy epidermal outgrowths are also seen in Riccia melanospora, though rarely Fig. Scales are violet coloured, multicellular and one celled thick structures Fig.
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.
Venter initial tier also divides by repeated transverse divisions to form a single layer of swollen venter.