Plant Reproduction Flashcards
When an insect carrying pollen lands on the flower describe the events that lead to seed formation
When it lands the stigma inside the flower brush against the insect. It is sticky so the pollen sticks to it. A pollen tube then grows down the style towards the ovary and enters the ovary via the micropyle (small hole in ovary) at this point fertilisation occurs and the ovule developed into a seed which developed into a fruit. (Ovule wall becomes seed coat)
What does the radicle become?
The first root
What does the plumule become
The first shoot
What does the cotyledon become
The first leaf and food store
What is function of the testa?
It covers and protects the embryo before germination (seed coat)
What is dormancy?
The period of time between fertilisation and germination
What is germination
The process by which a seed changes into a plant. Root, shoot appears the seed cost splits.
Why is water needed for germination
Water is needed in order to burst that tests and allows the radicle and plumule to develop. It also allows metabolic reactions to happen as it activates enzymes
Why is oxygen needed for seeds to germinate
Oxygen is needed for aerobic respiration to happen
Why is a warm temperature needed for germination?
A warm temperature not only lets the seed know when it should germinate but it also lets rapid enzyme reactions to happen.
What is a zygote?
The 1st cell after fertilisation when the diploid number has been restored.
What is the stamen made up of, where is it and what does it do?
Insect pollinated
The stamen is made up of the anther and the filament (which holds up the anther)
They are the long stick things inside the flower.
They produce pollen grains which stick or hook onto the insects. The anther and filament are firm and stiff to brush against the insects.
What is the stigma and where is it?
Insect pollinated
The stigma is also inside the flower and the stamen are on top of it. It is sticky so pollen grains stick onto it when an insect brushed past.
What do petals look like on insect pollinated flowers?
They are large and brightly coloured to attract insects
How else to insect pollinated flowers attract insects
They have sweet, sugary nectar which attracts insects.
Where is the stamen and what does it do?
Wind pollinated flower
The stamen is outside the flower and the anthers are loose on long filaments so pollen grains are released easily, the grains are smooth and lights so can be carried by the wind and not clump together
Where is the stigma and what does it do
Wind pollinated flower
It is outside and feathery to catch drifting pollen grains
What do the petals look like on a wind pollinated flower?
They are small and usually green or brown.
What is the definition of pollination?
The transfer of pollen from the anther to the stigma then ovule to allow fertilisation to take place.
What happens when pollen lands on the stigma?
A pollen tube is grown down the style and into the ovary, the nucleus of the pollen grains passes down the tube to fertilise the egg cell in the ovule (fertilisation). The embryo developed and the ovary forms the fruit and the ovules become seeds.
What is germination?
The process where a plant grows from a seed.
How do germinating seeds get their food before they can photosynthesise?
They use up their food stores until they can photosynthesise
What is a gamete?
Also known as a sex cell. A female and male gamete undergo fertilisation to become a zygote. In a plant the female gamete is the egg and the male gamete is the pollen.
What happens when plants asexually reproduce?
They produce a clone. Some plants have lateral buds on the outside which grows another plant others have side branches with plantlets on them (spider plant) and others produce runners which extend and grow a plant from that (e.g. Strawberry plants) this can be done artificially through tissue culture and taking cuttings
