Angiosperm reproduction Flashcards
(80 cards)
1
Q
What is the alternation of generations?
A
Diploid generation (sporophyte), haploid generation (gametophyte)
2
Q
Define: inflorescence
A
- Reproductive shoot bearing one or many flowers
- May arise from apical or axillary bud
- Terminates meristematic activity
3
Q
What are the 4 whorls of a flower?
A
- Calyx (sepals)
- Corolla (petals)
- Androecium (stamens)
- Gynoecium (carpels)
4
Q
Define: pedicel
A
Flower stalk
5
Q
Define: peduncle
A
Main axis from which a pedicel arises
6
Q
Define: receptacle
A
Part to which flower parts are attached
7
Q
Define: perianth
A
Sepals and petals
8
Q
Stamens are made up of:
A
Anther and filament
9
Q
Carpels are made up of:
A
Stigma, style, ovary
10
Q
Define: stigma
A
Where pollen lands
11
Q
Define: style
A
Long structure connecting stigma to ovary
12
Q
What sort of carpel is considered advantageous?
A
Fused carpels (as opposed to free)
13
Q
What are the three flower positions and according ovary positions?
A
Hypogynous, perigynous - superior ovary
Epigynous - inferior ovary
14
Q
Define: complete flower
A
All four whorls present
15
Q
Define: incomplete flower
A
One or more whorls missing
16
Q
Define: perfect flower
A
Carpels and stamens present
17
Q
What is a flower with stamens missing called?
A
Carpellate / pistillate flower
18
Q
What is a flower with carpels missing called?
A
Staminate flower
19
Q
Define: imperfect flower
A
Carpels or stamens missing
20
Q
Define: monoecious plant
A
Male / female flowers on same plant
21
Q
Define: diecious plant
A
Male / female flowers on different plants
22
Q
Gametes are produced inside ____________
A
Gametophytes
23
Q
What is the male gametophyte?
A
Pollen grain
24
Q
What is the female gametophyte?
A
Embryo sac
25
Define: microgamete
Male gamete, sperm
26
Define: microsporangia
Pollen sacs in anthers, contain microsporocytes
27
Define: tapetum
Innermost layer of pollen sac, breaks down to provide material and nutrients to coat the pollen grain
28
Define: microsporocyte
Diploid cells inside immature pollen sacs which divide to produce 4 haploid microspores
29
Define: microspore
Haploid cell that undergoes mitosis to form 2 cells: the generative cell and the tube cell
30
What does a pollen grain consist of?
Two celled male gametophyte (generative cell and tube cell), and the spore wall
31
Generative cell -> ???
2 sperm cells
32
Pollen grains have 2 walls:
Normal plasma membrane, then several coats (intine, exine)
33
Define: exine
- Outer layer of pollen grain, made from sporopollenin from tapetum
- Very resistant, protects from UV, dehydration, insect attack
34
Define: sporopollenin
- Comes from tapetum, forms exine on pollen grain
- Very resistant, protects from UV, dehydration, insect attack
35
Define: megasporangium
Ovule, contains megasporocytes
36
Define: megasporocyte
One cell in the megasporangium/ovule that undergoes meiosis, producing 4 megaspores, only one of which survives
37
How does a megaspore divide?
- Mitosis x3, producing a large cell with 8 nuclei, without properly dividing (8-nucleate embryo sac)
- Cytokinesis then occurs, but not between all cells, resulting in a 7-celled 8-nucleate embryo sac
-6 haploid cells, 1 diploid cell with polar nuclei
38
Define: integument
Outer layer around ovule, develops into seed coat
39
Define: nucellus
Central part of ovule inside integuments, embryo sac develops inside this
40
What are the 7 cells in an embryo sac?
1 egg cell, 1 polar nuclei, 2 synergids, 3 antipodals
41
Egg cell -> ???
Embryo
42
Polar nuclei -> ???
Endosperm
43
Define: protoandry
Male flower parts develop first
44
Define: protogyny
Female flower parts develop first
45
What does cross pollination require?
A vector e.g. animals, wind, water
46
Bird pollinated flowers...
Are often red or yellow, with little odour
47
Animal pollinated flowers...
Produce copious nectar
48
Nectar is produced in...
Nectaries
49
Define: pseudocopulation
Sexual deception, mimicking a female insect
50
Wind pollinated flowers...
Require large quantities of pollen, no colours or nectaries
51
What is unique about angiosperm fertilisation?
Double fertilisation
52
Write out the fertilisation process that leads to the sporophyte
Sperm (n) + egg (n) -> zygote (2n) -> embryo (2n) -> sporophyte
53
Write out the fertilisation process that leads to the endosperm
Sperm (n) + polar nuclei (2n) ->endosperm nucleus (3n) -> endosperm (3n)
54
What happens when pollen lands on the stigma?
- Viable pollen grains (pollen is very dry) take up water from the stigma surface, only if there is recognition between pollen / stigma
- Pollen grain then germinates, a pollen tube arises from a pore on the exine surface by the tube cell elongating
- The sperm cells and tube nucleus move together down the tube
- Pollen tube discharges two sperm cells into the female gametophyte within an ovule, through the micropyle
55
Define: micropyle
Opening in the surface of the ovule, through which the pollen tube penetrates
56
Embryo or endosperm development: which usually comes first?
Endosperm
57
Where are food reserves for the seed stored?
The endosperm, in some species; in others they are exported to the cotyledon
58
Zygote -> ???
Basal cell and terminal cell, eventually embryo
59
Define: basal cell
- One of two daughter cells produced by zygote division
- Forms suspensor which holds embryo to parent plant
60
Define: terminal cell
- One of two daughter cells produced by zygote division
- Gives rise to most of the embryo (at this stage pro-embryo)
61
When does protoderm develop?
Very early in embryo formation
62
What are the stages of embryo formation?
Pro-embryo -> globular stage -> heart stage -> torpedo stage
63
What happens to the suspensor?
Undergoes programmed cell death, ends attachment
64
??? -> seed coat
integuments
65
Define: plumule
The epicotyl, young leaves and shoot apical meristem
66
What happens during dormancy?
Meristematic activity stops, embryo becomes dehydrated
67
Ovary -> ???
Fruit
68
Ovary wall ->
Pericarp
69
Define: pericarp
- Part of fruit derived from ovary wall
- Has different layers ( endocarp, mesocarp, exocarp)
70
Define: simple fruit
Derived from single carpel or fused carpels e.g. pea, nectarine
71
Define: aggregate fruit
Derived from a single flower with multiple carpels, multiple fruitlets produced e.g. raspberry
72
Define: multiple fruit
Where an inflorescence / group of flowers develops appearance of one fruit e.g. pineapple, banksia
73
Define: true fruit
All parts derived from an ovary
74
Define: accessory fruit
Some fruit parts derived from non-ovary parts - this occurs for inferior ovaries where the ovule develops while fused to the receptacle
75
Define: parthenocarpic fruit
Seedless
76
Define: elaiosome
Food body for ant dispersal, full of lipids, proteins, starch, sugars, vitamins that is attached to seed
77
What emerges first during germination?
Radicle (embryonic root)
78
Define: radicle
Embryonic root
79
Define: epigeous
Germination where cotyledon is dragged out of the ground, hypocotyl is the hooked part that emerges from the ground
80
Define: hypogeous
Germination where the cotyledon remains below ground, epicotyl is the hooked part that emerges from the ground
