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Soral evolution in filicopsida

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BANGABASI COLLEGE (MORNING)

Soral evolution in filicopsida

  1. 1. SORAL EVOLUTION IN FILICOPSIDA Chayanika Chowdhury;BOTANY HONS.;2ND SEM 3/19/2019
  2. 2. :CONTENTS: 1. DEFINITION OF SORUS. 2. TYPES OF SORUS. 3. INDUSIAL PROTECTION. 4.POSITION OF SORUS. 5.CONCLUSION. 6. REFERENCE. 7. ACKNOWLEDGEMENT.
  3. 3. INTRODUCTION Definition of sorus: Sorus, plural sori, in botany, brownish or yellowish cluster of spore-producing structures (sporangia) usually located on the lower surface of fern leaves. A sorus may be protected during development by a scale or flap of tissue called an indusium.
  4. 4. TYPES OF SORUS 1. THE SIMPLE SORUS. 2. THE GRADATE SORUS. 3. THE MIXED SORUS.
  5. 5. :THE SIMPLE SORUS: The Simplices are primitive and extend to the Paleozoic. All sporangia within a sorus may be at the same stage of development (Simplices) The sporangia in such a sorus development simultaneously and all of them mature together.   E.g. Ophioglossum and Osmunda.
  6. 6. :THE GRADATE SORUS: In such cases the internal space within the radial sorus gets filled by overlapping sporangia. Overcrowding results and there is no space for the proper dehiscence of sporangia and consequently some of them do not dehisce. The Gradate with an oblique annulus, occupy a middle position and have been discovered in the Mesozoic. EX: Dicksonia, Loxosoma, Trichomanes, Cyathea, Als ophila, etc Dicksonia Trichomanes
  7. 7. :THE MIXED SORUS: The spores are released in a staggered fashion and even if the environmental conditions are not favorable when the spores are initially released; this problem is solved by a constant crop of spores over a given length of time. Mixtae annulus is present but in a vertical fashion. e.g. Polypodiaceae(Adiantum,Pteris,Pteridium, Davallia) Polypodiaceae
  8. 8. : INDUSIAL PROTECTION : The indusium may be formed as an epidermal outgrowth covering receptacle and sporangia (true indusium) or it may merely be the in turning of the margin of the leaf to protect the sporangia (pseudo indusium or false indusium).
  9. 9. :POSITION OF SORUS IN FERNS: The Ophioglossales are group of interesting ferns in which the sporangia are marginal in position. 1. In Maeattia, Angiopteris,Danaea etc…the sori are elongagated and are situated below the lateral veins. 2. In christensia the sori are naked, circular and are irregular arranged between the lateral veins. 3. In Adiantum the sporangia develop on the underside of special marginal flaps of lamina that become reflexed and protect the sorus 4. . 5. The sori in Mattoniaceae are ventral in position and are usually arranged in two rows on either side of the midrib. In Glecheniaceae, the sporangia from distinct sori on the ventral surface of the leaves. 6. The sporangia in Osmunda ,Davalia, Trivhomanes and many other ferns are also marginal in position
  10. 10. 7. In Salviniales the smaller sporocarp contain many microsporangia each and the larger ones contain one or more megasporangia per sporocarp. 8. The sporocarp in Marsilea enclose sori that contain both micro and megasporongia. 9. In Marsileales and the Salviniales the sporangia develop in sori that are borne within distinct structure called the Sporocarp.
  11. 11. :CONCLUSION: FROM THE ABOVE PRESENTATION ,WE CAN CONCLUDE THAT THE SORUS IS SPECIALISED REPRODUCTIVE STRUCTURE.THE PRESENT ADVANCED STRUCTURE OF SORUS HAS DERIVED FROM SUCCESSSIVE CHANGE IN THE STRUCTURE.THE SORUS HAS BEEN COVERED BY INDUSIUM FOR BETTER PROTECTION. DIFFERENT MECHANISM OF SPORE DEHISCENCE HAS BEEN EVOLVED .THE GERMINATION OF SPORES HAS BECOME MUCH MORE EASIER . THIS IS THE EVOLUTION OF SORUS IN FILICOPSIDA.
  12. 12. REFERENCES: http://www.users.miamioh.edu/smithhn/chrispage.html Pteridophyta By: prof.S.P.Khullar Botany for Degree Students-Pteridophyta, 3/e
  13. 13. ACKNOWLEDGEMENT: WE ARE GRATEFUL TO OUR TEACHERS FOR BEING SUPPORTIVE AND HELPFUL ATTITUDE AND ALSO GRATEFUL TO OUR COLLEGE LIBRARY FOR PROVIDING US BOOKS AS PER OUR REQUIREMENTS.
  • WasifAhmed35

    Mar. 29, 2021
  • SwethaRajkumar1

    Nov. 25, 2020
  • SuryaSuresh36

    Oct. 26, 2019

BANGABASI COLLEGE (MORNING)

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