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State the structure & function of the floral parts including: Sepal, petal,stamen,carpel
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tarix | 17.01.2018 | ölçüsü | 480 b. | | #21217 |
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State the structure & function of the floral parts including: Sepal, petal,stamen,carpel) State the structure & function of the floral parts including: Sepal, petal,stamen,carpel) State that the Pollen grain produces male gamete. State that the Embryo sac produces an egg cell & polar nuclei. Define the terms: pollination, self-pollination Outline methods of pollination including: cross-pollination & self pollination
Define the term: fertilisation. Define the term: fertilisation. Outline seed structure & function of following: testa, plumule, radicle, embryo, cotyledon Explain embryo & food supply (endosperm or seed leaves) Classify plants as monocotyledon or dicotyledon & distinguish between them. Make reference to non-endospermic seed. Outline fruit formation. Outline seedless fruit production
Outline fruit & seed dispersal and give with examples of wind/water/animal/self dispersal Outline fruit & seed dispersal and give with examples of wind/water/animal/self dispersal Explain & emphasise the need for dispersal Define the term dormancy. State advantages of dormancy. Explain dormancy in agricultural & horticultural practice. Define the term: Germination. Explain the factors necessary for and role of digestion and respiration in germination. Outline the stages of seed development
State that vegetative propagation is asexual reproduction State that vegetative propagation is asexual reproduction Give 1 example of vegetative propagation from stem, root, leaf, bud Compare reproduction by seed and by vegetative reproduction Outline 4 methods of artificial propagation in flowering plants
Sepal : To protect the flower (and to prevent it from drying out Sepal : To protect the flower (and to prevent it from drying out Petals : To attract insects to the flower for pollination
Stamen : To produce the pollen grains in the anthers. (Each pollen grain produces two male gametes, one of which can fertilise an egg cell) Stamen : To produce the pollen grains in the anthers. (Each pollen grain produces two male gametes, one of which can fertilise an egg cell)
Carpel : To produce the ovules (Each ovule contains an egg cell inside an embryo sac) Carpel : To produce the ovules (Each ovule contains an egg cell inside an embryo sac)
Transfer of pollen from the anther to the stigma of a flower of the same species Transfer of pollen from the anther to the stigma of a flower of the same species
Self pollination Self pollination Transfer of pollen from an anther to a stigma of the same plant
Animal Pollination Wind Pollination
Petals brightly coloured, scented with nectaries Petals brightly coloured, scented with nectaries Small amounts of sticky pollen Anthers inside petals Stigmas sticky, inside petals
Petals small, not coloured brightly Petals small, not coloured brightly Anthers outside petals Stigmas large, feathery and outside petals Pollen Large numbers, light, dry and small
Fertilisation is the fusion of the male (n) and female (n) gametes to produce a zygote (2n) Fertilisation is the fusion of the male (n) and female (n) gametes to produce a zygote (2n) The pollen grain produces the male gametes Embryo sac produces an egg cell and polar nuclei
The pollen grain produces the male gametes The pollen grain produces the male gametes Embryo sac produces polar nuclei and an egg cell
The zygote grows repeatedly by mitosis to form an embryo The zygote grows repeatedly by mitosis to form an embryo An embryo consists of a plumule (future shoot), a radical (future root) and cotyledons (food stores needed for germination)
The endosperm nucleus (3N) divides repeatedly to form the endosperm in endospermic seeds. This endosperm acts as a food store for the developing seed The endosperm nucleus (3N) divides repeatedly to form the endosperm in endospermic seeds. This endosperm acts as a food store for the developing seed e.g. maize
In non-endospermic seeds the endosperm is used up in the early stages of seed development so the food is stored in the cotyledons In non-endospermic seeds the endosperm is used up in the early stages of seed development so the food is stored in the cotyledons e.g. bean
Classified according to two features: Classified according to two features: Number of cotyledons (Seed leaves) Presence of endosperm - Present – Endospermic e.g. maize
- Absent – Non-endospermic e.g. broad bean
The ovule becomes the seed The ovule becomes the seed The ovary becomes the fruit
A fruit is a mature ovary that may contain seeds A fruit is a mature ovary that may contain seeds The process of fruit formation is stimulated by growth regulators produced by the seeds
Can be formed in two ways Can be formed in two ways Genetically Either naturally or by special breeding programmes
Growth regulators e.g. auxins Growth regulators e.g. auxins - If large amounts of growth regulators are sprayed on flowers fruits may form without fertilisation
- e.g. seedless grapes
Need for dispersal Need for dispersal - Minimises competition for light, water etc.
- Avoids overcrowding
- Colonises new areas
- Increases chances of survival
Wind
Wind Wind - Sycamore and ash produce fruit with wings
- Dandelions and thistles produce fruit with parachute devices
- Both help the disperse the seeds more widely using wind
Water Water Light, air filled fruits that float away on water
Animal Animal - Edible fruit
- Animals attracted to bright colours, smells and food
- Seed passes through digestive system unharmed
- E.g. strawberries, blackberries, nuts
Animal Animal - Sticky fruit
- Fruits with hooks that can cling to the hair of an animal and be carried away
- E.g. burdock, goose grass
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Self Self - Some fruits explode open when they dry out and flick the seed away
- E.g. peas and beans
A resting period when seeds undergo no growth and have reduced cell activity or metabolism A resting period when seeds undergo no growth and have reduced cell activity or metabolism
Plant avoids harsh winter conditions Gives the embryo time to develop Provides time for dispersal
Some seeds need a period of cold before they germinate Some seeds need a period of cold before they germinate It may be necessary to break dormancy in some seeds before they are planted for agricultural or horticultural purposes This can be done by placing them in the fridge before they are planted
The re-growth of the embryo after a period of dormancy, if the environmental conditions are suitable The re-growth of the embryo after a period of dormancy, if the environmental conditions are suitable
Water Water Oxygen Suitable temperature Dormancy must be complete
Water Water - Activates the enzymes
- Medium for germination reactions e.g. digestion
- Transport medium for digested products
Oxygen Oxygen - Needed for aerobic respiration
Digestion Digestion - Of stored food in endosperm and cotyledon
Respiration - To produce ATP to drive cell division
Events in germination cease when the plants leaves have developed and the plant has started to photosynthesise
Water is absorbed Water is absorbed Food reserves are digested Digested food is moved to the embryo New cells are produced using amino acids Glucose is turned into ATP to drive cell division Plumule emerges above ground New leaves begin to photosynthesise
Outline the main stages of sexual reproduction in plants Outline the main stages of sexual reproduction in plants
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