bryophyta&TERIDOPHYTA

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INTRODUCTION LIFE HISTORY OF BRYOPHYTA 1. Characteristics of Bryophytes. 2. Life cycle of Bryophyte. 3. Division into: (a) Liverworts (b) Mosses

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They are non-flowering plants. They grow in moist places. They are autotrophic. They do not have any vascular tissue because their body is so thin that tissue can directly collect the water through their body. BRYOPHYTES

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They are land plants but the require water to complete sexual reproduction. so they are known as amphibious plants. They have got leaf like structures green in colour . They have also root like structure called rhizoids .They show clear cut Alternation of generation in their life cycle.

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Main plant body of the bryophyte is haploid. It produce gametes ,hence is called gametophyte. Sex organs in bryophytes are multicellular. The male sex organ is called antheridium. They produce biflagellate antherozoids. The female sex organ called archegonium is flask shaped and produces a single egg.

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The antherozoids are released into water where they come in contact with archegonium .An antherozoids fuses with the egg to produce the zygote. Zygotes do not undergo reduction division immediately. They produce a multicellular body called sporophyte. Some cells of the sporophyte undergo reduction division to produce haploid spores. These spores germinate to produce gametophyte.

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Life cycle of Bryophyte

Mosses are one group of bryophytes: 

Mosses are one group of bryophytes

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The liverworts grow usually in moist, shady habitats such as banks of streams ,marshy ground, damp soil, bark of trees and deep in the woods. Plant body is thalloid. e.g Marchantia. The leafy members have tiny leaf like appendages in two rows on the stem like structure. Asexual reproduction in liverworts takes place by fragmentation of thalli, or by the formation of specialized structures called gemmae. Liverworts

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MARCHANTIA HEPATICA NOBILIS Liverwort`s Images

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Adult gametophyte which appears from protonema is differentiated into Rhizoids Axis or stem ,Phylloid or leaves. At the base of stem ,branched, obliqely septate, multicellular colourless rhizoids are present. Mature rhizoids turn brown. Stem is erect and branches only once in extraaxillary fashion MOSSES

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Stem is covered with small ,simple, sessile leaves which are arranged in a spiral fashion. Leaf is green , ovtate in shape with acute apex .It has a distinct mid-rib .Margin is slightly serrated. Main branch in young gametophore behaves as male shoot and side branch as female shoot.

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Antheridia and archegonia are borne at the apices of branches. Antheridia are surrounded by perigonial leaves and archegonia with perichaetial leaves. The plants are autoecious and monoecious.

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Life cycle of moss

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Picture of moss plant

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The pteridophytes include horsetails and ferns . These organs posses well-differentiated vascular tissues. They are found in cool, damp, shady places though some may flourish well in sandy- soil conditions. The main plant body is sporophyte which is differentiated into true root,stem, leaves. PTERIDOPHYTES

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The leaves in pteridophyta are small (microphylls) as in selaginella or large (macrophylls) as in ferns.

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Characteristics of Pteridophyta 1.Diploid sporophyte generation is predominant. 2.Sporophyte plant body has true roots, stem and leaves with well developed vascular system. 3.Asexual reproduction takes place by spores. 4.Most pteridophytes are homosporous; only a few show heterospory. 5.Spores are produced in multicellular sporangia after meiosis in spore mother cells.

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6.Gametophyte is haploid, multicellular, green and an independent structure. 7.Sex organs, antheridia and archegonia are multicellular. 8.Antherozoids (sperms) are spirally coiled and multi flagellate. 9.Opening of sex organs and transfer of male gametes to archegonium for fertilization are dependent on water. Further, fertilization takes place inside the archegonium.

Life cycle of fern: 

Life cycle of fern

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Ferns

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The End