logging in or signing up pollination divyashree1993 Download Post to : URL : Related Presentations : Let's Connect Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Copy embed code: Embed: Flash iPad Dynamic Copy Does not support media & animations Automatically changes to Flash or non-Flash embed WordPress Embed Customize Embed URL: Copy Thumbnail: Copy The presentation is successfully added In Your Favorites. Views: 550 Category: Entertainment License: All Rights Reserved Like it (0) Dislike it (0) Added: July 01, 2013 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... Premium member Presentation Transcript PowerPoint Presentation: POLLINATION BY DIVYASHREE.B.RPowerPoint Presentation: POLLINATION The term pollination refers to the transfer and deposition of pollen on the stigma of the flower . It is of two types: Natural pollination : which occurs naturally in plants. Induced pollination : which is carried out by artificial means. Natural pollination is of two types: Self-pollination Cross pollinationPowerPoint Presentation: SELF-POLLINATION It involves the transfer of pollen grains from the anther to the stigma of the same flower(Autogamy) or another flower of the same plant (Geitonogamy). Examples: Ground Nut Barley Pea plantPowerPoint Presentation: Self-pollination is promoted by certain floral adaptation . Mirabilis jalapa Vinca rosea Cleistogamy : It is a phenomenon in which the flowers do not open at the time of fertilization . Violaceae Homogamy: It refers to the maturation of sex organs at same time. balsaminaceaePowerPoint Presentation: ADVANTAGES OF SELF-POLLINATION Parental charecters are preserved indefinitely. The flowers need not to be large. Fragrance and nectar production is not required, which saves considerable nutrient material of plants. DISADVANTAGES OF SELF-POLLINATION Continued self-pollination may lead to weakening of the off-springs. Seeds produced will be poor in quality. The defective character of plants cannot be eliminated.PowerPoint Presentation: CROSS POLLINATION It involves the transfer of pollen grains from the anther of a flower to the stigma of another flower of different plant(Allogamy). Pollination between flowers of different genetic constitution is known as xenogamy. Examples: Sunflower, date palm, maize etc. Cross pollination is favoured by certain adaptations. Dicliny : plants bearing unisexual flowers posses only one kind of sex organs(male or female). Example: Papaya MulberryPowerPoint Presentation: Dichogamy : It refers to maturation of sex organs at different time period. It shows two conditions 1. Protandrous : here anthers mature before stigma. Example: Rubiaceae, Malvaceae, Labiatae. 2. Protogynous : here stigma matures before the anthers. Example: Mangolia, Michalia, Adhatoda.PowerPoint Presentation: Heterogamy : The phenomenon of bearing two types of morphological dissimilar flowers. Ex: Primrose. It bears two types of flowers. Long-styled or Pin eyed: Flowers bearing long style and short stamens. Short-styled or thrum eyed: Flowers bearing short style and long stamen.PowerPoint Presentation: Herkogamy : In certain flowers, morphological barriers develop which makes self pollination impossible. Example: Calatropis Zeuxine Self-Sterility : Flowers in which pollens are incapable of causing fertilization. Example: Maize.PowerPoint Presentation: AGENTS OF CROSS POLLINATION In angiosperms, pollens are immotile and thus, have to be carried to the stigma by external pollinating agents. Depending upon their nature the agents may be Biotic agents: Insects, Birds, Snails etc. Abiotic agents; wind, water. BIOTIC AGENTS Entomophily : It refers to the pollination brought about by insects. Examples: Salvia, Yucca, Ficus.PowerPoint Presentation: ii . Ornithophily : It refers to the pollination brought about by birds. Examples: Salmalia, Erythrina, Callistemon. iii . Cheiropterophily : It refers to the pollination brought about by bats. Examples: Adansonia, Eperua falcata.PowerPoint Presentation: iv . Malacophily : It refers to the pollination brought about by snails & slugs. Examples: Alocasia, Lemna, Colocasia. v. Myrmecophily : It refers to the pollination brought about by ants. Examples: Medicago sativa, Melitotus officinalis.PowerPoint Presentation: vi. zoophily : It refers to the pollination brought about by animals. Examples: Arctium, Galium aparine. ABIOTIC AGENTS Anemophily : It refers to the pollination brought about by winds. Examples: Wheat, maize, coconut.PowerPoint Presentation: Hydrophily: It refers to the pollination brought about by water. It is of two types; 1. Ephydrophily : Pollination occuring on the water surface. Examples: Elodes, Hydrilla. 2 . Hyphydrophily : Pollination occuring beneath the water surface. Examples: Najas, Ceratophyllum.PowerPoint Presentation: ADVANTAGES OF CROSS-POLLINATION Off-springs are healthier. New varities may be produced. Helps in increase seed production in cereals. DISADVANTAGES OF CROSS-POLLINATION The pollination is not always certain. A large number of pollens are to be produced to ensure chances of pollination. If in a crossing, a diseased plant gets involved, it will give weak off-springs.PowerPoint Presentation: THANK YOU You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.