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FLOWERS AS REPRODUCTIVE STRUCTURES . ABBOTTS . FLOWER STRUCTURE. Parts of a Flower. Stigma Style Ovary. Carpel/Pistil (female). Stamen (male). Anther Filament. petals. ovule. sepal. Parts of the Flower. Peduncle: flower stalk

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  3. Parts of a Flower Stigma Style Ovary Carpel/Pistil (female) Stamen (male) Anther Filament petals ovule sepal

  4. Parts of the Flower Peduncle: flower stalk Receptacle: part of stalk bearing the floral organs, at base of flower Sepal: leaflike structures at flower base, protects young flower bud Calyx: all the sepals together form the calyx Petal: located inside and above the sepals, often large and colourful, sometimes scented, sometimes producing nectar Stamen: male part of the flower, consist of the anther and filament, makes pollen grains Pollen: grains containing the male gametes Pistil/Carpel: female part of the flower, consist of the stigma, style and ovary Ovule: located in the ovaries, carry female gametes

  5. FLOWER ANATOMY Anther Stigma Filament Pollen Tube Style Ovary Stamen Ovule Petal Sepal Carpel

  6. PURPOSE OF EACH FLOWER PART • A. Carpel: • Stigma- Covered in a sticky substance that pollen grains can stick to • Style- Raises the stigma away from the ovary to decrease pollen contamination • Ovary- Protects the ovule after fertilization; becomes the fruit • Pollen Tube- What the pollen travels through to reach the eggs in the ovule • Ovule- Like the egg in animals; once fertilization takes place it will become the seed.

  7. PURPOSE OF EACH FLOWER PART B. Stamen: • Anther- Contain pollen sacs. The sacs release pollen on to the outside of the anthers where wind or other organisms can transfer the pollen to the carpel for fertilization. • Filament- Stalk of the anther C. Petal: Petals are used to attract insects into the flower, they may have guidelines on them and be scented. D. Sepal: Sepals protect the flower whilst the flower is developing from a bud.

  8. FLOWER FUNCTIONS • Flowers contain the reproductive organs • Stamens – male parts • Carpel – female part • Flowers attract pollinators who transport pollen from the anther to the stigma

  9. DRAWING • Use a sharp HB pencil • Drawing must be big enough e.g. Half a page • Leave enough space around the drawing for labels • Labels must be written in ink and not cover the diagram itself • Label lines must be in ink, drawn with a ruler and must not cross each other • The line must not end with an arrow and it must indicate the exact part that is being labelled • The drawing should have a heading stating what the diagram shows

  10. POLLINATION BY POLLINATORS • Pollinators are organisms that aid in the transfer of pollen from anther to stigma, to allow for fertilization • Flowers get pollinated and pollinators get food • Pollination takes place through: • insects • wind • birds • water

  11. POLLINATION • Is the transfer of ripe pollen containing the male gametes from the anthers to the stigma to allow for fertilization

  12. Self Pollination = when the pollen from one flower is used to fertilize the eggs produced by that same flower; true-bred flowers

  13. Cross Pollination = when the pollen from one flower is used to fertilize a different flower of the same type

  14. POLLINATION BY POLLINATORS • Pollinators are animals that move pollen from anther to stigma, to allow for fertilisation • Pollinators visit flowers to get food (pollen and nectar) • Flowers get pollinated and pollinators get food • Pollinators are mostly insects (some are vertebrates)

  15. ADAPTATIONS OF INSECT-POLLINATED FLOWERS • The flowers have large conspicuous petals in bright colours • Sweet scent to attract moths and butterflies • Offer a reward of nectar and/pollen • Anthers and stigma are often inside the flower • Pollen grains are often sticky or spiky (stick to the insects • Large quantities of pollen are produced • Flowers have nectar guides to help the insect find the centre of the flower

  16. SOUTH AFRICAN INSECT-POLLINATED FLOWER • Bluish in colour – bees pollinate blue and yellow flowers • Delicate sweet scent • Sturdy with a landing platform on which the bee lands • Have nectaries which secrete nectar (sweet liquid) to attract and feed pollinators • Flowers are open in the daytime • Pollen grains stick to the bodies of bees Salvia africana-caerulea

  17. ADAPTATIONS OF BIRD POLLINATED FLOWERS • Flowers produce a large quantity of dilute nectar • Flowers are bigger than insect pollinated flowers • Flowers are red and open in the daytime • Flowers are sturdy – birds are rough • Flowers have little or no scent – birds have a poor sense of smell • Ovules are protected from the probing beaks • Pollen grains stick together in clumps – bird picks up a lot of pollen in one visit • Flowers are erect with a landing platform

  18. SOUTH AFRICAN BIRD-POLLINATED FLOWER  PAGE 57 • Flowers stand at the tips of long stalks • Flowers have a sturdy landing place for sunbirds • Flowers have three orange sepals and three blue petals • Two of the petals join together to form a dart to hold the stamens, style and nectary • Dart provides a perch for the sunbird strelitziareginae

  19. The structure and pollination of the flowers is fascinating. The hard, beak-like sheath from which the flower emerges, is called the spathe. This is held at right angles to the stem, and has the appearance of a bird's head. Each spathe contains 4 to 6 flowers, and these emerge one at a time from the spathe. Each flower consists of 3 clear yellow sepals and 3 deep purple petals. The yellow sepals give the appearance of a crest on the 'bird's' head. Two of the purple petals are joined together around the stamens and the style to form an arrow-like structure. The third purple petal is visible as a small scale. EXTRA STUFF DART FORMED BY BLUE PETALS SEPALS SPATHE

  20. ADAPATATIONS OF A WIND-POLLINATED FLOWER Page 57 • Small, inconspicuous flowers without any bright petals • Petals are often absent for better exposure to wind • No nectar or produced • No scent • Male flowers are often arranged in catkins (clusters) that move freely in the wind • Long thin filaments hang outside the flower, easily shaken by the wind • Anthers are large and well exposed to catch the wind • Pollen grains are small (non sticky) and light and easily carried by the wind • Stigmas are long and feather- like with a large surface area and outside the flower to trap pollen

  21. Examples of inflorescence types. WORKBOOK An inflorescence is a group or cluster of flowers arranged on a stem

  22. SOUTH AFRICAN WIND POLLINATED FLOWER • Simple flowers with all the features of wind pollinated flowers except the anthers are not visible Thamnochortuspellucidus in flower

  23. Female inflorescence  Male inflorescence Wind distributes the pollen to the female infloresence – caught by bracts and directed to hidden female flowers The male infloresence hangs down on a flexible stalk to shake the pollen free


  25. PAGE 59 SIMILARITIES BETWEEN BIRD AND INSECT POLLINATED FLOWERS • Produce less pollen than wind pollinated flowers; there is no wastage as the pollen is taken directly between plants • Both produce nectar • Have pollen grains with spikes etc so that they stick together and can attach easily to the pollinator • Have stigmas and anthers either just outside or inside the flower • Might be affected by disease organisms that are carried to the flower along with pollen • Have obvious petals


  27. FERTILISATION Fertilisation is the combining of nuclei of a male and female gamete to form a zygote

  28. POLLINATION • Is the transfer of ripe pollen containing the male gametes from the anthers to the stigma to allow for fertilization

  29. WHAT HAPPENS AFTER FERTILISATION? • The zygote forms an embryo inside the ovule • The rest of the ovule forms endosperm (food for the germinating seed) • The outer layer of the ovule forms the testa (hard, dry, protective layer) • The mature ovule = seed

  30. WHAT HAPPENS AFTER FERTILISATION? • The ovary grows and encloses and protects the seeds =fruit

  31. THE END

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