9.4 Reproduction In Plants Flashcards
What are the processes of pollination?
- Pollination -> pollen carried from the anther of one flower to the stigma of another
- Fertilisation -> pollen tube grows from the stigma to the ovary through the style -> pollen delivered to ovum and fertilisation occurs
- Seed dispersal -> once the seed developed in ovule, it is ready for dispersal
What is cross pollination
The transferring of pollen (through wind, water and animals)
What is a flower?
Reproductive organ of angiospermophyte (enables plants to sexually reproduce)
How does flowering occur?
From the changes in gene expression in the shoot apex
What are photochromes?
Leaf pigments which detect periods of light and dark
What is photoperiodism?
It is the plant response to light/dark for advantageous time of the year
What does inactive form of phytochrome (Pr) do?
It is converted into the active form when absorbs red light
(High levels at night )
What does active form of phytochrome (Pfr) do?
Active form is is broken down into the inactive form when it absorbs far red light
Active form will gradually revert to inactive form in absence of light (light reversion)
(Levels increase during the day)
What is a mutualistic relationship?
Both species benefit from interaction
(Flower-> means of sexual reproduction, animal -> source of nutrition)
Label and explain structure of a flower
Label and explain the structure of a seed
What effect does Pfr do to short day plants?
Inhibits flowering
So Pfr levels must be low to flower
What effect does Pfr have on long day plants?
Activated flowering
Per levels must be high to flower
What does the critical length need to be for short distance plants?
The periods of darkness need to be greater than the critical length (normally in summer)
What does a horticulturalist do to trigger flowering for short day plants?
Covering the plant for -12ams a day
