1. Reproduction in plants
Flowering

2. Understandings
Flowering involves a change in gene expression in the shoot apex.
The switch to flowering is a response to the length of light and dark periods in many plants.
Most flowering plants use mutualistic relationship with pollinators in sexual reproduction
Success in plant reproduction depends on pollination, fertilization and seed dispersal.

3. Flowering and gene expression
When a seed germinates, a young plant is formed that grows roots, stems and leaves and these are called vegetative structures, which indicates that it is currently in vegetative phase.
Flowers can only be produced when something stimulates the plant to change from the vegetative phase into reproductive phase
Stimulus is a change in the length of light and dark periods.

4. Short day plants and Long day plants
Chrysanthemums: Irises:
Flower in autumn when the nights have become long enough
Flower in summer when the nights have become short enough

5. Flowering controlled by phytochrome

7. Read page 430 and annotate the diagram

8. Sunlight contains red wavelength light
Pr is converted to Pfr
Much less in sun light
Pfr is unstable and is converted back into Pr in the dark

9. Gene Expression and Flowering
Pfr has been found to be the active form of phytochrome
Receptor proteins are present in the cytoplasm of leaf cells to which Pfr (not Pr) binds
These proteins will then cause transcription of genes needed for flowering
Long day plants
Large amounts of Pfr remain to bind to the proteins and promote transcription
Short day plants
The receptor protein inhibits the transcription of the flowering genes when bound to Pfr.
At the end of a long night there is very little Pfr so there is no inhibition and the gene is transcribed
Short day plants – Pfr inhibits flowing
Long day plants – Pfr promotes flowing

10. The mRNA...
…was transcribed from a flowering time gene (FT gene). FT mRNA is transported to the shoot apical meristem (via the phloem).
...here it is translated into a FT protein. This binds to a transcription factor and may flowering genes are activated. The meristematic cells differentiate (gene expression) and the reproductive phase begins.
mRNA
mRNA
Phytochrome

11. Complete question on page 430
Exam Q

12. How could plants be manipulated to flower out of season?
Exam Q

13. Flower Structure
Draw a picture of an animal pollinated flower

14. Flower Structure
Draw a picture of an insect pollinated flower

15. Flower Dissection

16. Pollination
Pollination and evolution
Pollination is the transfer of male gametes of to the female part of the flower (Stigma).
Pollinators such as bees are attracted because they can gain food (nectar) and the pollen will be able to attach itself onto the bees and potentially land on a stigma. This double-beneficial relationship is called Mutualism. Symbiotic relationship.
Also attracted by scent and colours

17. Fertilization
Fertilization occurs once a pollen has landed on the stigma and a reaction called the enzymatic reaction will create a tube (Pollen tube) within the stigma that allows the gamete from the pollen to travel to the ovary. Two male nuclei enter the olule.
Here the male and female gametes fuse.
One male nuclei fuses with the egg and the other fuse with the polar nuclei to produce and triploid endosperm
Ovule becomes the seed and ovary becomes the fruit
Tube nucleus

18. Seed dispersal FIND SOME INTERESTING WAYS THAT SEEDS ARE DISPERSED

19. Structure of Seeds
Draw the internal and external structure of a seed

20. Exam Q

21. Planning a germination experiment

22. Keywords
Vegetative phase - The phase before reproductive phase and can be stimulated into the reproductive phase when the stimulus is present (Light). This can be spotted when there are vegetative structures present.
Pollinators - Animals that help transfer the pollen. Examples are honey bees and hummingbirds.
Mutualism - Both organisms receive benefits. Example is when the honey bees or hummingbirds obtain nectar from the flower and help spread the pollen.
Enzymatic Reaction - A reaction that only occurs once a pollen lands on top of the stigma and it creates a tube called the pollen tube. The pollen tube allows the sperm from the pollen to swim towards the ovary.