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E-content generation of undergraduate classes with special reference to the Orchidaceae

E-content generation of undergraduate classes with special reference to the Orchidaceae. VISHAL SHARMA P.G.GOVT.COLLEGE FOR GIRLS, SECTOR 11, CHANDIGARH-INDIA.

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E-content generation of undergraduate classes with special reference to the Orchidaceae

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  1. E-content generation of undergraduate classes with special reference to the Orchidaceae VISHAL SHARMA P.G.GOVT.COLLEGE FOR GIRLS, SECTOR 11, CHANDIGARH-INDIA

  2. The flowering plants satisfy man’s requirements for food, shelter, clothing and drugs, besides adding to his aesthetic values. Their latter utility accounts for a highly lucrative trade in floriculture. Plants worth 800 billion US $ (dollars) were traded last year. Till very recently, the trade primarily revolve around roses, lilies, carnation, chrysanthemums, tulips etc. but the trend is now fast shifting in favour of orchids for their long -lasting flowers of myraid shapes, sizes and colours.

  3. Inflorescence: Usually a spike (Orchis) , sometimes raceme(Dendrobium) or solitary terminal(Cypripedium) • Flower:Bracteate,sessile,complete,zygomorphic,mostlybisexual,epigynous and are mostly trimerous • Perianth:Usuallysix;in two whorls of three each,outer one free whereas posterior tepal of inner whorl is modified into lip or labium and acts as landlig place for insects.The labium adnate to base of column.Theperianth lobes are variously coloured and bear diverse and variegated patterns.

  4. Androecium:Theandroecium is representedby one or two or three stamens .In Orchis the single fertile stamen lies in outer whorl and the inner whorl has only staminodes.The stamens and styles fused to form a column like structure called columnorgynandriumorgynastemium.The column is usually present opposite the labellum.The anthers are bithecous,dehiscence longitudinal Gynaecium: Tricarpellary, syncarpous, Inferior, unilocular, Placentationparietal,stigmas three with two fertile lobes and modification of third sterile lobe into a structure called the rostellum and usually positioned in the centre of column • Fruit:Capsule • Seed: Non-endospermic

  5. Pollination:The flower has a nectary concealed in the spur of labellum or at the base of column.The insects land land on the labellum and tries to reach the nectary and bite itor drill its tissue to suck the juice contained in it.While entering the the flower the insect displaces the the rostellumor some parts.In doing so it exposes the sticky mass of pollinia and comes in contact with it.This sticky mass of pollinia becomes cemented to the insect while it is drilling the honey and when the insect enters the next flower ,pollinia come in contact with the stigma.A very interesting pollination mechanism in Ophrys where flower resemble to female species of bees and male insects attracted by flowers of Ophrysdue to female like appearance and on reaching male insects get excited,carry out matting movements and in so attach pollinia to their bodies.

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