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DRM Biology Y10 DRM Biology Y10 1 1 Plant Plant reproduction reproduction The The plant plant cycle cycle Asexual Asexual reproduction reproduction Sexual Sexual reproduction reproduction : : The The flower flower Pollination Pollination Fruit Fruit and and seed seed formation formation Seed Seed dispersal dispersal Seed Seed germination germination

Plant reproduction y10

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Summary on reproduction in plants for IGCSE Biology.

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  • 1. Plant reproductionThe plant cycleAsexual reproductionSexual reproduction: The flower Pollination Fruit and seed formation Seed dispersal Seed germination DRM Biology Y10 1
  • 2. The plant cycle in nonflowering plants DRM Biology Y10 2
  • 3. The plant cycle in floweringplants DRM Biology Y10 3
  • 4. Asexual reproduction inplants By stolons and runners (as in grasses) By spores (as in ferns and mosses) By tubers (as in potatoes) By bulbs (as in onions) By grafts (used mostly in gardening) In this case, all individuals are genetically identical to the parent plant. DRM Biology Y10 4
  • 5. Examples of asexualreproduction in plantstubers bulbs Fern spores stolons DRM Biology Y10 5
  • 6. Sexual reproduction in flowering plantsPlants produce reproductive organs calledflowers.These flowers have specialised structureswhich are either female or male.Sexual cells called gametes are made in thereproductive organs.The gametes fuse in a process calledfertilisation.Following fertilisation, fruits and seeds developfrom parts of the formerBiology Y10 . DRM flower 6
  • 7. Parts of the flower DRM Biology Y10 7
  • 8. Parts of the flower petalantherfilament stigma sepal style ovule ovary DRM Biology Y10 8
  • 9. PollinationIt is the transfer of the pollen grain from the anther to the stigma.This can be done in the same flower (self-pollination) or in different flowers (cross-pollination). DRM Biology Y10 9
  • 10. Wind-pollinated flowersFlowers are usually verysmall, with no petals andno scent.Anthers and stigmas areexposed to the wind.Stigmas are hairy orfeathery to trap the pollengrains blown by the wind. stigmaPollen grains are smooth,light and very small to beeasily carried by the wind. antherExample: grasses DRM Biology Y10 10
  • 11. Insect-pollinated flowersHave big, colourfulpetals to attractinsects.Have nectar and/orscent to attractinsects orhummingbirds.Stamen and stigmasinside the corolla.Pollen grains are big,and with hooks toattach to insectslegs. DRM Biology Y10 11
  • 12. FertilisationThe pollen grain grows a pollen tube which will carry the nucleus of the male gamete to the ovule, to meet the female egg cell.Fertilisation is the fusion of the nucleus of the male gamete with the nucleus of the female gamete. DRM Biology Y10 12
  • 13. Fruit and seed formationOnce fertilised, The OVARY develops into the FRUIT. The OVULES become the SEED. The petals, stamen and stigma shrivel and fall. DRM Biology Y10 13
  • 14. Fruit and seed dispersalSeeds need to bedispersed away fromthe parent plant.This can be achievedby wind, water,animals, or self-explosion.Each seed hasspecial structuresadapted to the way itis dispersed. DRM Biology Y10 14
  • 15. Seed structure Plumule (future shoot) Seeds are protected by Radicle (future the testa. root) All seeds cotyledon have a food Testa (seed reserve cover) (cotyledon). Radicle The embryo isEMBRYO formed by the plumule and Plumule Testa the radicle. DRM Biology Y10 cotyledon 15
  • 16. Seed germination Germination in a monocot plant (wheat) Germination in a dicot plant (bean)All seeds must have water suitable water,temperature and oxygen togerminate.Some seeds may also need lightDRM Biology Y10 to activate the 16germination process.