LIFE CYCLE OF RICCIA PDF

Life cycle of Riccia Riccia shows alternation of generations a haploid gametophyte generation and a diploid sporophyte generation alternate each other. The haploid generation is called the gametophyte because it undergoes sexual reproduction to produce male and female gametes. Production of gametes involves mitosis, so the gametes are also haploid. The male and female gametes of Riccia fuse to form a diploid zygote which grows into the next generation the diploid sporophyte generation. Sporophyte produces spore tetrads.

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Life cycle of Riccia Riccia shows alternation of generations a haploid gametophyte generation and a diploid sporophyte generation alternate each other. The haploid generation is called the gametophyte because it undergoes sexual reproduction to produce male and female gametes. Production of gametes involves mitosis, so the gametes are also haploid. The male and female gametes of Riccia fuse to form a diploid zygote which grows into the next generation the diploid sporophyte generation.

Sporophyte produces spore tetrads. Production of spore involves meiosis. Hence, there is a return to the haploid condition. The haploid spores give rise to the gametophyte generation. The life cycle of Riccia shows regular alternation of gametophytic and sporophyte generations. Fertilization Water is indispensable for the process of fertilization. The antherozoids reach the mouth of the archegonuim through the medium of water. The mucilaginous mass of the neck region absorbs water and swells and as a result the cover cells get separated.

This results in the formation of a passage which facilitates the entry of sperms or antherozoid. The antherozoids enter the mouth of the archegonuim, travel through the neck and reach the vicinity of the egg.

One of the antherozoids penetrates egg cell and the fertilization is effected. Ultimately by the union of the nuclei of male and female gametes, a zygote is formed. The zygote contains 2n number of chromosomes i. Sporophyte Generation The diploid zygote is the first cell of the sporophyte generation. This cell secretes a wall around it soon after the fertilization and enlarges in size and nearly fills the cavity of the venter.

Afterwards it undergoes division and attains two celled stage.

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life cycle of riccia pdf

Gametophytic Phase of Riccia: The plant body of Riccia is gametophytic and gametophytes are fleshy, prostrate and dichotomously branched. Repeated dichotomy results into a typically rosette like appearance Figs. In Riccia cruciata only two dichotomy result in a cruciate form Fig. Each branch of the thallus is linear, wedge-shaped or obcordate. Thallus is mm long and 1. However, in R. Dorsal Surface: The dorsal surface is light green or dark green body, each branch having a thick midrib.

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Life Cycle of Riccia (With Diagram) | Hepaticopsida

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