Fruits and Seeds

3.4 Plant Fertilisation

Notes


Fertilisation

- Germinate (tube grows downward)
   - Species specific, only same pollen can germinate
- Pollen ----- pollen tube (style) ---> Ovule

Formation of seed


1. Fertilisation
       Pollen nucleus + Ovule -------> Zygote -----> Embryonic Plant
2. Coating
       Outside ovule forms seed coat (TESTA)
3. Food Store
       Cotyledons (along with Zygote) - food stores to support plant
4. Fruit        
       Ovary walls thicken (energy used - sugars/proteins) ----> Fruit

Petals and Sepals

Stamen System

Carpal System

3.3b Wind Pollination

Notes


Anther (male), PlantB ----Wind (air)----> Stigma (female), PlantB

Adaptions

1. Pollen = Lightweight Grains
     - Wing Feature to move efficiently through air
2. Anthers = hang clear of basic flower structure
     - Exposed to wind
3. Stigma = Large Surface Area
    - Feather-like structure to 'catch' pollen in wind
    - Exposed to wind

Differences to Insect Pollinated (e.g. Grass, Wind Pollinated)

Waste of energy (no need to attract nectaries)
  - No Colours
  - No Scent
  - No Nectaries

3.3a Insect Pollination

Notes


Cross-Pollination = Transfer of:

Pollen (from anther, containing MALE nuclei), PlantA ---INSECTS--> Stigma (female), PlantB

Plant A


Adaptations to attract insects
    Lure:
     - Coloured Petals
     - Scents
    Reward:
     - Food in nectaries - fructose
     - Pollen (source of protein)

---> Male (Stamen)
       Anther (produces pollen grains)
       Filament (supports anther)

---> Female (Carpal)
       Stigma (pollen lands)
       Style (stigma ---> ovary)
       Ovary (contains eggs - OVULES)