3 Reproduction in plants Flashcards
If gametes are produced, what kind of reproduction is it?
It is sexual reproduction.
If fertilisation takes place, what kind of reproduction is it?
It is sexual reproduction.
If there is genetic variation in the offspring, what kind of reproduction is it?
It is sexual reproduction.
Which type of reproduction has survival value in a changing environment?
Sexual reproduction.
Which type of reproduction has survival value in a stable environment?
Asexual reproduction.
What do most types of asexual reproduction in plants involve?
Most involve some part of the plant growing, and then breaking away from the parent plant before developing into a new plant.
What is another type of asexual reproduction?
To grow plants from cuttings.
What is a cutting?
It is a method of producing new plants by taking a piece of a shoot and planting it in compost. An example of asexual reproduction.
How does the experiment with cuttings take place?
A piece of a plants stem, with a few leaves attached, is cut from a healthy plant. The cuttings are planted into a damp soil or compost, where it will grow roots and develop into a new plant.
What kind of gametes do plants produce?
Specialised, haploid gametes in their flowers.
Where are the male gametes contained within?
The pollen grains.
What are pollen grains?
It is a structure in plants that contains the male gamete.
Where are the female gametes contained within?
The egg cells or ova
What are the ova?
The female gamete
What must happen for sexual reproduction to take place?
The male gametes must be transferred to the female gametes.
What is the transfer of these two gametes called?
Pollination.
What is pollination?
It is the transfer of pollen from an anther to a stigma.
What follows pollination?
Fertilisation takes place and the zygote formed develops into a seed, which, in turn, becomes enclosed in a fruit.
What is a seed?
It is the structure that forms from the ovule following fertilisation. Contains the embryo plant and its food store.
What is a fruit?
It is a structure containing a seed or several seeds. Which is formed by the ovary following fertilisation.
How are the gametes produced?
By meiosis in structures in the flowers.
Where are pollen grains produced?
In the anthers of the stamens.
What is the anther?
It is the part of the stamen where pollen grains are produced.
What is the stamen?
It is the male reproductive organ in plants, consisting of the anther and a stalk called the filament.
Where are the ova produced?
In the ovules or ovaries.
What are the ovules?
They are the structure within the ovaries in plants. Cells in the ovules divide by meiosis to produce ova.
What are the ovaries?
It is the female reproductive structure in the carpel of a flower, which contains ovules.
What happens during pollination?
Pollen grains are transferred from the anthers of a flower to a stigma.
What is a stigma?
It is the part of the carpel of a flower which receives the pollen during pollination.
What happens if the pollen grains are transferred within the same flower?
It is called self-pollination.
What happens if the pollen grain are transferred to a different flower?
It is called cross-pollination.
How can these types of pollination take place?
By wind or by insect in either case.
What must happen for fertilisation to take place?
The nucleus of the pollen grain must fuse with the nucleus of the ovum, which is inside the ovule in the ovary.
What is the first step of fertilisation?
To transfer the nucelus to the ovum, the pollen grain forms a pollen tube, which grows down through the tissue of the style and into the ovary.
What is the second step of fertilisation?
Here it curves around to enter the opening in an ovule.
Whats the third step of fertilisation?
The tip of the tube dissolves and allows the pollen grain nucleus to move out of the tube and into the ovule.
What is the fourth step of fertilisation?
Here it fertilises the ovum nucleus.
What is the pollen tube?
It is the tube that grows from a pollen grain and down through the style to allow the transfer of the male gamete to the ovule for fertilisation.
What is the style?
It is a part of the carpel of a flower. Stalk connecting the stigma to the ovary, through which the pollen tube grows.
What are the steps for seed and fruit formation?
1) The zygote develops into an embryonic plant with small root (radicle) and shoot (plumule).
2) Other contents of the ovule develop into a food store for the young plant when the seed germinates.
3) The ovule wall becomes the seed coat or testa.
4) The ovary wall becomes the fruit coat; this can take many forms depending on the type of fruit.
What is a diagram for how a plum fruit forms?
What is the reason for the position of stamens in insect-pollinated plants?
Enclosed within glower so that insect must make contact.
What is the reason for the position of stamens in insect-pollinated plants?
Enclosed within glower so that insect must make contact.
What is the reason for the position of stigma in insect-pollinated plants?
Enclosed within glower so that insect must make contact.
What is the reason for the position of stigma in wind-pollinated plants?
Exposed so that it can catch pollen blowign in the wind.
What is the reason for the type of stigma in insect-pollinated plants?
Sticky so pollen grains attach from insects.
What is the reason for the type of stigma in wind-pollinated plants?
Feathery, to catch pollen grains blowing in the wind
What is the reason for the type of petals in insect-pollinated plants?
Large to attract insects.
What is the reason for the type of petals in wind-pollinated plants?
Small
What is the reason for the colour of petals in insect-pollinated plants?
Brightly coloured to attract insects.
What is the reason for the colour of petals in wind-pollinated plants?
Not brightly coloured, usually green.
What is the reason for the nectaries in insect-pollinated plants?
Present- they produce nectar, a sweet liquid containing sugars as a ‘reward’ for insects.
What is the reason for the nectaries in wind-pollinated plants?
Absent.
What is the type of pollen grains in insect pollinated plants?
Larger, sticky grains or grains with hooks, to stick to insects’ bodies.
What is the type of pollen grains in wind pollinated plants?
Smaller, smooth, inflated grains to carry in the wind.
What is a diagram showcasing the main structures in an insect-pollinated flower?
What is a diagram showcasing the main structures in a wind-pollinated flower?
What does a seed contain?
A plant embryo consisting of a root (radicle), shoot (plumule) and one or two seed leaves.
What are cotyledons?
They are seed leaves. May act as a food store in seed.
Where is the food store found?
Either in the cotyledons or another part of the seed.
What happens during germination to the food store?
It is used up, providing the nutrients to allow the radicle and plumule to grow.
What does the radicle do with the nutrients from the food store?
It grows down into the soil, where it will absorb water and mineral ions.
What does the plumule do with the nutrients from the food store?
It grows upwards towards the light, where it can start the process of photosynthesis
When is germination considered to be over?
Once the small plant (seedling) is able to photosynthesise, germination is over.
What are examples of dicotyledonous / dicots plants?
- Peas.
- Beans.
What does dicotyledonous / dicots mean?
It is a plant with two seed leaves. (Two cotyledons).
What are examples of monocotyledonous / monocots plants?
- Seeds of grasses.
- Other narrow leaved plants.
- Irises.
- Orchids.
What does monocotyledonous / monocots mean?
It is a plant with one seed leave. (One cotyledon).
What is an image that represents the germination of a broad bean?
Where is the food store of beans or peas present in?
The cotyledons, and it consists mainly of starch and protein.
Where is the food store located in monocots such as maize?
There is a separate food store for starch.
What does germination mean?
It is the sequence of events taking place when the embryo in a seed begins to develop into a young plant.
What happens when seeds are dispersed from the parent plant?
They are usually very dry, containing about 10% of water.
Why is this low water content necessary for the seed?
It restricts a seed’s metabolism, so that it can remain alive but dormant (inactive) for a long time, sometimes for many years.
What happens when a seed germinates in relation to its metabolism?
The seeds dormancy comes to an end. The seeds food store is broken down by enzymes and respired aerobically.
What are the following conditions needed for germination?
- Warm temperatures, so that enzymes can act efficiently.
- Water, for chemical reactions to take place in solution.
- Oxygen, for respiration.
What is an image of the test tubes used when investigating the conditions needed for germination?
What are the conditions that the tubes are held under when investigating the conditions needed for germination?
Tube A: Seeds on wet cotton wool, maintained at 20C (room temperature).
Tube B: Seeds on dry cotton wool, maintained at 20C.
Tube C: Seeds in boiled water, with a thin surface layer of oil; maintained at 20C.
Tube D: Seeds on wet cotton wool, placed in a refrigerator at 4C.
What are precautionary measures taken for tube C?
The water in tube C has been boiled to remove dissolved oxygen. The layer of oil (e.g. cooking oil) keeps out oxygen from the air.
What results would we collect?
After a few days the seeds in the control tube (A) will start to germinate. There will be no germination in tubes B or C. The seeds in tube D may eventually start to germinate, but much more slowly than in tube A.
What is the structure of the seed?
What does the testa do?
Tough outer seed coat that protects embryonic plant
What does the micropyle do?
Small pore in outer covering of seed that allows passage of Water via osmosis.
What is the plumule (epicotyle)?
It is the embryonic shoot.
What is the radicle?
It is the embryonic root.
Where does starch get turned into glucose?
In the cotyledon.
