apple dissection!

3.4 Plant Fertilisation

pollen grains on stigma
- germinate
- tubes begin to grow down stigma
- pollen tube grows into the ovule
- nucleus travels down pollen tube -> to ovule

(http://www.landlearn.net.au/newsletter/2008term2/images/Seed-rotated.jpg)

1. Pollen nucleus + ovule --> zygote grows into embryonic plant (Fertilisation)
2. Outside ovule - seed coat forms (testa)
3. Cotyledons - food stores for the seedling (develops in the zygote) - supports plant until it develops its first set of leaves
4. Thickening of the walls of the ovary/carpel - puts energy into the walls like sugar, protein - forms fruit of the plant

Adaptation

relates to things happening efficiently

in lilies, gene for sepal mutated - changed to look like petals
to attract more insects

- efficiency -

signals
liles:
petal - signal to bee - nectar
scent
sugar (reward)
----- plants invest energy to get the insect to pollinate it

grass:
grass doesn't invest energy in colour, scent, or sugar
- produces lots of pollen because its reproductive strategy is risky (wind)
invest energy in other things

adaptations/efficiency - putting/investing energy into things

vector for pollination - insect/wind
other vectors include birds, animals, water

Lily dissection

pictures from the internet:

Ovules

the carpel and ovary

(pictures from http://farm3.static.flickr.com/2180/2439202538_d07a47a1a1.jpg, http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20102/Bio%20102%20lectures/Seed%20Plants/pistil.jpg)

pictures from the lesson coming soon

3.3b - Wind pollination

Anther => Stigma
Air - wind

Adaptations
1. Light pollen grains - with wing feature (moving through air more efficiently)

(http://chestofbooks.com/flora-plants/flowers/Field/images/Winged-pollen-of-the-fir.jpg)

2. Anthers hanging away from basic flower structure - exposed to wind

3. Stigma

- large surface area

- far away from flower structure
- feather-like structure to catch pollen grains from the wind
- exposed to wind



Grass
- No colour in petals (no need to attract insects)
- No scent
- No nectaries
(Waste of energy for plant)

3.3a - Insect pollination

Pollination - Transfer of pollen grains from anther to stigma
Pollen contains male nuclei
Flower needs to attract insects

Cross pollination - pollen goes from one plant to the other

Adaptations to attract insects

Signals
colour petals (insects can see colour)
scents

Value
food (Nectaries/fructose)
pollen as a source of protein

Male and female parts of the plant

Stamen - male part of the plant
Anther (pollen grains)
Filaments - stalk

Carpel - female part
Stigma - where pollen grains fall
Style - connects stigma to ovary
Ovary - contains eggs (ovules)