Plant Reproduction Flashcards
1
Q
Characteristics of Sexual Reproduction
A
Involves 2 parents
Forms a zygote.
New plant is different
Meiosis is involved
2
Q
Characteristics of Asexual Reproduction
A
Involves 1 parent
New plant is identical to parent
Mitosis is involved
Example: Strawberry plant produces runners.
3
Q
Function of Sepal
A
To protect the flower and to prevent it from drying out
4
Q
Function of Petals
A
To attract insects to the flower for pollination
5
Q
Function of Stamen
A
To produce the pollen grains in the anthers. Each pollen grain produces two male gametes, one of which can fertilise an egg cell
6
Q
Function of Anther
A
Produces pollen
7
Q
Function of Filament
A
Holds the anther in place
8
Q
Function of Carpel
A
To produce the ovule. Each ovule contains an egg cell inside an embryo sac
9
Q
Function of Stigma
A
Where pollen lands after pollination
10
Q
Function of Style
A
Pollen travels down this
11
Q
Function of Ovary
A
Contains ovules
12
Q
What are the female parts of the flower
A
Carpel (stigma, style and ovary)
13
Q
What are the male parts of the flower
A
Stamen (anther and filament)
14
Q
What is pollination?
A
Pollination is the transfer of pollen from the anther of a stamen to the stigma of a carpel of the same species.
15
Q
What are the adaptations of insect-pollinated plants?
A
Petals brightly coloured to attract insects
Flower is scented with sweet nectar to attract insects
Anthers and Stigmas inside petals
Stigma is sticky
16
Q
What are the adaptations of wind-pollinated plants?
A
Petals not coloured brightly, usually green
No nectar or scent
Anthers and Stigmas outside petals
Stigmas large, feathery to catch pollen on the wind
17
Q
Methods of pollination:
A
insect pollination and wind pollination
18
Q
What is self pollination
A
Transfer of pollen from an anther to a stigma of thesame plant
19
Q
What is cross pollination
A
Transfer of pollen from the anther to the stigma of adifferent plantof the same species
20
Q
What are the the 5stages of reproduction
A
1.Pollination
2.Fertilisation
3.Seed Formation (and Fruit)
4.Seed Dispersal
5.Germination
21
Q
What is the process of pollen gran development
A
by meiosis a diploid microspore mother cell becomes a tetrad of pollen and then four immature pollen grains by seperation, these then divide by mitosis into two haploid nuclei (tube nucleus and generative nucleus) when they mature, the walls of another anther dry and split and then they are released for pollination.
22
Q
What is the function of the tube nucleus
A
Forms the pollen tube
23
Q
What is the function of the tube nucleus
A
Forms the pollen tube
24
Q
What happens to generative nucleus
A
Divides by. Mitosis to form two sperm nuclei which are the male gametes which each play a role in double fertilisation
25
What structure contains one or more ovules in a plant?
The ovary
26
What are the walls of the ovary called?
Integuments
27
What is the small opening between the integuments called, and what is its function?
It is called the micropyle, and it allows the entry of a pollen tube
28
What type of cell in the ovule undergoes meiosis to form four haploid cells?
The megaspore mother cell (diploid, 2n).
29
How many haploid cells remain after meiosis, and what happens to the others?
One haploid cell remains; the other three disintegrate.
30
What is the name of the remaining haploid cell after meiosis?
The immature embryo sac.
31
How many times does the nucleus of the embryo sac divide, and by what process?
It divides three times by mitosis.
32
How many haploid nuclei are formed within the embryo sac after the mitotic divisions?
Eight haploid nuclei.
33
How many of the eight haploid nuclei in the embryo sac will eventually disintegrate?
Five nuclei will disintegrate.
34
How many female gametes remain after disintegration of the nuclei?
Three female gametes remain.
35
What do two of the remaining female gametes form within the embryo sac?
They form the polar nuclei.
36
What does the last remaining female gamete form?
It forms the egg cell.
37
What forms the pollen tube after pollination?
The pollen tube nucleus forms the pollen tube.
38
Through what structure does the pollen tube move to reach the ovary?
The pollen tube moves down the style to the ovary.
39
What happens to the generative nucleus as it moves down the pollen tube?
It divides by mitosis to form two haploid sperm nuclei, which are the male gametes.
40
What happens to the tube nucleus when the pollen tube reaches the embryo sac?
The tube nucleus disintegrates.
41
What process occurs when the pollen tube reaches the embryo sac?
Double fertilization occurs.
42
During double fertilization, what does one sperm nucleus fuse with, and what is the result?
One sperm nucleus fuses with the egg cell, forming a diploid zygote.
43
What does the second sperm nucleus fuse with, and what is formed as a result?
The second sperm nucleus fuses with the two polar nuclei to form a triploid endosperm.
44
What will the diploid zygote develop into?
The diploid zygote will develop into an embryo.
45
What is the ploidy level of the endosperm nucleus formed during fertilization?
The endosperm nucleus is triploid (3n).
46
What process does the zygote undergo to form an embryo?
The zygote grows repeatedly by mitosis to form an embryo.
47
What are the three main components of an embryo?
Plumule (future shoot)
Radicle (future root)
Cotyledons (food stores for germination)
48
What is the function of the triploid (3N) endosperm nucleus?
The triploid endosperm nucleus divides repeatedly by mitosis to form the endosperm, which acts as a food store for the developing seed.
49
What is the difference between non-endospermic and endospermic seeds?
In non endospermic seeds, the endosperm is used up in the early stages of seed development and the cotyledon is used for food
In endospermic seeds, the endosperm is not completely absorbed ans remains as a food source for the developing embryo (e.g., maize).
50
Give an example of a non-endospermic seed.
Broad bean (where the endosperm is fully absorbed by the embryo).
51
Give an example of an endospermic seed.
Maize (where the endosperm is not fully absorbed by the embryo).
52
What does the integument develop into during seed and fruit development?
The integument develops into the hard seed wall, called the testa.
53
What does the ovule containing the embryo sac develop into?
The ovule containing the embryo sac develops into the seed.
54
What does the ovary develop into during seed and fruit development?
The ovary develops into the fruit.
55
How are plants classified based on the number of cotyledons? And examples
Monocotyledons have one cotyledon (e.g. maize).
Dicotyledons have two cotyledons (e.g. broad bean).
56
How are plants classified based on the presence of endosperm?
• Endospermic seeds contain endosperm (e.g. maize).
• Non-endospermic seeds do not contain endosperm (e.g. broad bean).
57
What are the characteristics of a monocotyledon?
• One cotyledon
• Parallel venation
• Scattered vascular bundles
• Petals usually in multiples of three
58
What are the characteristics of a dicotyledon?
• Two cotyledons
• Netted venation
• Vascular bundles in a ring
• Petals usually in multiples of four or five
59
What stimulates the process of fruit formation?
Fruit formation is stimulated by growth regulators produced by the seeds.
60
Name two ways seedless fruits can be formed.
1. Genetically, either naturally or through breeding programs (e.g., seedless oranges).
2. By spraying growth regulators like auxins on flowers (e.g., seedless grapes).
61
Why is seed dispersal important for plants?
• Minimizes competition for light, water, and nutrients
• Avoids overcrowding
• Helps colonize new areas
• Increases the chances of survival for the seed
62
What are some methods of seed dispersal by wind?
Sycamore and ash produce fruit with wings, while dandelions and thistles have parachute devices for wind dispersal.
63
Give an example of a fruit that disperses seeds by water.
Coconuts and water lilies have air-filled fruits that float and are dispersed by water.
64
How do animals help in seed dispersal?
• Animals eat edible fruit and the seeds pass through their digestive system unharmed (e.g., strawberries, blackberries).
• Sticky fruits with hooks attach to animals’ fur and are carried away (e.g., burdock, goose grass).
65
What is an example of self-dispersal in plants?
Peas and beans use self-dispersal by exploding open when they dry out, flicking seeds away.
66
What is seed dormancy?
Seed dormancy is a resting period during which seeds undergo no growth and have reduced cell activity or metabolism.
67
What are the advantages of seed dormancy?
• Helps the plant avoid harsh winter conditions
• Gives the embryo time to develop
• Provides time for seed dispersal
68
How is dormancy applied in agriculture and horticulture?
Some seeds require a cold period before germination, which can be simulated by placing them in a fridge before planting.
69
What is germination?
Germination is the re-growth of the embryo after dormancy when the conditions are suitable.
70
What factors are necessary for germination?
• Water: Activates enzymes, aids digestion, helps break the testa.
• Oxygen: Needed for respiration.
• Suitable temperature: Allows for optimal enzyme activity.
71
What are the events in Germination
- Water is absorbed
- Food reserves are digested
- Digested food is moved to the embryo
- Glucose is turned into ATP/energy by respiration for cell division
- New cells are produced
- Radicle breaks through the testa
- Plumule emerges above ground
- New leaves begin to photosynthesise
72
Q: What is asexual reproduction in plants?
A: It involves only one parent, and the offspring are genetically identical to the parent.
73
What is vegetative propagation?
A form of asexual reproduction in plants that does not involve gametes, flowers, seeds, or fruits, and produces genetically identical offspring.
74
How many natural types of asexual reproduction are there in plants, and what are they?
There are four natural types: runners, tubers, plantlets, and bulbs.
75
How does a new plant form during vegetative propagation?
Part of the plant becomes separated from the parent and divides by mitosis to grow into a genetically identical new plant.
76
What parts of the parent plant are specially modified for vegetative propagation?
Stem, root, leaf, and bud.
77
What are runners in vegetative propagation?
Runners are horizontal stems running over the soil surface; their terminal buds send up new shoots (e.g., strawberry, creeping buttercup).
78
What are stem tubers and how do they function in vegetative propagation?
Stem tubers are swollen underground stem tips; buds (eyes) on the tuber produce new shoots (e.g., potato).
79
What is a root tuber in vegetative propagation?
A root tuber is a swollen fibrous root that stores food, and new plants develop from a side bud at the base of the old stem (e.g., dahlia, lesser celandine).
80
How do plantlets contribute to vegetative propagation?
Some plants produce plantlets along the edges of their leaves; once the plantlets reach a certain size, they fall off and grow into new plants (e.g., Lily, Kalanchoe).
81
What are bulbs in vegetative propagation?
Bulbs contain an underground bud with leaves swollen with stored food. The apical bud grows into a new shoot, while side buds (lateral buds) may also develop into new shoots (e.g., onion, daffodil, tulip).
82
Q: What are the advantages of sexual seed formation in plants?
Cross-pollination ensures variation (allowing evolution), plants are more resistant to disease, dispersal reduces competition, and seeds can remain dormant to survive unfavorable conditions.
83
What are the disadvantages of asexual seed formation (vegetative reproduction)?
No variations, all plants are susceptible to disease, overcrowding and competition occur, and no seeds are formed, meaning no dormancy.
84
What are the disadvantages of sexual seed formation in plants?
It is a complex process, depends on outside agents for seed dispersal, has slow growth to maturity, and can be wasteful (e.g., petals, pollen, fruit).
85
What are the advantages of asexual vegetative propagation?
It is a simple process, no outside agents are needed, rapid growth occurs, and it is not wasteful.
86
What are the four types of artificial vegetative propagation?
Cuttings, grafting, layering, and micropropagation (tissue culture).
87
What are cuttings in artificial vegetative propagation?
Parts of a plant, usually shoots, are removed and allowed to form new roots and leaves (e.g., busy lizzie, geranium).
88
What is grafting in artificial vegetative propagation?
Part of one plant (scion) is attached to a rooted part of another plant (stock) to combine useful qualities from both (e.g., apple trees).
89
What is layering in artificial vegetative propagation?
A branch is bent over and pinned to the earth at a node. When roots develop, the branch is separated from the parent plant (e.g., blackberry, gooseberry).
90
What is micropropagation (tissue culture) in plants?
Cells are removed from a plant, grown in a special medium with nutrients and growth regulators, forming a callus that develops into a plantlet. It is used for mass production of house plants and crops like bananas and strawberries.
91
What is cloning in plant reproduction?
Cloning is the production of genetically identical offspring through asexual reproduction. All offspring are produced by mitosis and are examples of clones.
