Plant reproduction notes

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  • Created on: 15-05-14 18:53
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Plant Reproduct ion- Sexual
Structure of a flower
Structure Function
Sepals Protect unopened flower bud
Petals May be brightly coloured to attract insects
Stamens Male parts of flower consisting of anther held up
by filament
Anthers Produce haploid male sex cells (pollen grains)
by meiosis
Filament Holds up anther
- The transfer of pollen from the anther Stigma Top of female part of flower (carpel)- collects
to the stigma pollen grains
- Self pollination (transfer from anther to
Style Supports stigma- male gamete travel down it to
stigma of same flower):
female ovules
- Pollen comes loose from stamens
- Stigma from same flower collects Ovary Produces haploid female sex cells (ovules) by
pollen meiosis
- Cross pollination (transfer from anther
of one plant to stigma of another): Nectaries Produce sugary nectar to attract insects. At
- Pollen sticks to insect as it visits base of plant so pollinator must come into
to collect food contact with anther
- Insect travels to another plant of
same type
- Pollen on insect sticks to stigma on other plant
After pollination
1. Pollen tube grows down style
2.Pollen grain nucleus moves down pollen tube ovary
3.Fertilisation (= fusion of nuclei of male and female gametes) occurs
4.Ovary wall hard and dry (brazil nut) or succulent and fleshy (plum) fruit (fertilised ovary)
disperses seeds. Sepals + petals + stamen + stigma +style wither
5.Carpel fruit. Ovules seeds. Ovule walls testa
Dispersal (to stop competition for resources, e.g. Light, water, space) methods
- Wind- Light (sometimes with wings to catch the wind)
- Water
- Animal internal- fruits eaten seeds have indigestible coat so pass through system
- Animal external- seeds have small hooks to attach to fur
- Explosive mechanism- pod bursts open when ripe seeds thrown far from plant
Germination (when plant emerges from seed + begins growth) conditions
1. Water testa splits as seed expands radical grows downwards + plumule grows upwards
3.Warmth = sign that conditions favourable for growth

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Structure Function
Testa Protection of seed
Embryo Grows into new plant
Food store Contains starch = energy for growing
Flower Insect pollinated Wind pollinated
Stamen Enclosed within flower so insect Exposed so wind can easily blow pollen
positions must make contact away
Stigma positions "" Exposed to catch pollen
Stigma type Sticky pollen grains from insect Feathery catch pollen grains in wind
Petal sizes Large attract insects Small
Petal colours Bright attract insects Green (not bright)
Nectaries Present- nectar = insects reward Absent…read more

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Plant Reproduct ion- Asexual
- E.g.…read more


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