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SEXUAL REPRODUCTION IN PLANTS

SEXUAL REPRODUCTION IN PLANTS. Sexual Reproduction in Plants. In flowering plants, the male and female reproductive organs are contained within the flower. The female reproductive organ is called the pistil , which is made up of the stigma , style , ovary and ovules .

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SEXUAL REPRODUCTION IN PLANTS

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  1. SEXUAL REPRODUCTION IN PLANTS

  2. Sexual Reproduction in Plants • In flowering plants, the male and female reproductive organs are contained within the flower

  3. The female reproductive organ is called the pistil, which is made up of the stigma, style, ovary and ovules. • Stigma = sticky lip of the pistil that captures pollen grains • Style = stalk that supports the stigma • Ovary = swollen base of pistil containing the ovules • Ovules = sacs containing female gametes

  4. The male reproductive organ is the stamen, which is made up of the anther, pollen grains and the filament. • Anther = where the pollen is produced and stored • Pollen grains = cases containing the male gametes (sperm) • Filament = stalk that supports the anther

  5. Pollination occurs when pollen grains from the anthers reach the stigma of the pistil • Two types of Pollination: • Self-pollination – male and female gametes come from the same plant • Cross-pollination – Gametes come from two different parents • Pollination does not ensure that fertilization occurs.

  6. During the video, make a note of: • The two strategies that plants use to promote cross-pollination. • What do flowers do to attract pollinators? • Why is cross-pollination important? • What does the dandelion flower do when cross-pollination does not occur? • How do some plants prevent self-fertilisation? (2 strategies) • Why is the tiger lily called a “perfect” flower? http://www.youtube.com/watch?v=4YQ5q1cjEU4

  7. Insects (pollinators) and wind • Change shape and colour of petals, colourful petals, sweet smell • Results in fertilisation and the next generation of plants, increases genetic variation • Stigma bends over and picks up pollen off the style. • Chemically recognise their own sperm and prevent zygote from developing; the male parts and female parts are not synchronised on the same plant, e.g. corn • Perfect flowers have both male and female organs in one flower.

  8. The pollen grain (containing sperm) grows an extension (called the pollen tube) down into the ovary • enters the ovule where it fertilises one egg. • Fertilisation has taken place and a zygote is formed. • zygote grows through mitosis to form an embryo with a leaf, root and a stem surrounded by nutrients contained within a protective layer (seed coat).

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