Reproduction in Plants Flashcards
1
Q
Sexual Reproduction definition
A
a fusion of 2 compatible gametes or sex cells
2
Q
end of vegetative stage =?
A
start of reproductive
3
Q
specialized reproductive structure
A
flower
4
Q
flower function
A
produce haploid gametes
ensure fertilization takes place
5
Q
flower whorls
A
androecium
gynoecium
calyx
corolla
6
Q
2 main events in sexual reproduction
A
meiosis + fusion of gametes
production of dissimilar plants
7
Q
variation is important because?
A
evolution of species
8
Q
3 steps in sexual reproduction
A
1) pre-fertilization - formation of gametes
2) fertilization - formation of zygote
3) post-fertilization - embryogenesis
9
Q
Dithecous meaning
A
Having two lobes
10
Q
Structure of anther
A
Dithecous and Tetrasprorongiate
11
Q
Wall of mature anther consist of
A
- Epidermis
- Endothecium
- Middle layer
- Tapetum
12
Q
Microspore is aka
A
pollen grain
13
Q
Epidermis
A
the outermost, protective layer
tabular cells
14
Q
Endothecium
A
sub-epidermal
radially elongated cells
fibrous thickening
15
Q
The middle layer
A
thin-walled (1-2 layers)
disintegrates in mature anther
16
Q
Tapetum
A
innermost nutritive layers
encloses sporogenous tissue
17
Q
sporogenous tissues
A
made of sporogenous cells
each gives rise to microspore tetrad
18
Q
Microsporogenesis
A
each microspore mother cell divides meiotically to form four haploid microspores or pollen grains.
19
Q
Structure of Microspore
5 points
A
non-motile haploid unicellular single nucleus marks beginning of male gametophyte
20
Q
2 layers of microspore
A
exine
intine
21
Q
intine
A
inner
cellulose and pectin
22
Q
exine
A
outer
sporopollenin
resistant to chemicals
has germ pores
23
Q
sporopollenin
A
complex, nonbiodegradable substance
either smooth or sculpted
24
Q
germ pores
A
are formed when exine is thin
growth of pollen grain during germination
25
development of male gametophyte includes
2 mitotic division
26
1st mitotic division
```
vegetative cell (bigger, naked, nutritive, irregular shaped nucleus)
generative cell (small, thin-walled, floats in the cytoplasm of the vegetative cell)
```
27
2nd mitotic division
the generative cell gives rise to 2 non-motive male gametes
28
the generative cell gives rise to 2 non-motive male gametes in ___?
(place)
either pollen grain or pollen tube
29
where are pollen grain shed from
anther
30
The generative cell gives rise to 2 non-motive male gametes that happen mostly in ___?
angiosperms
31
female whorl
gynoecium
32
gynoecium individual
carpel
33
free carpel
apocarpous
34
fused carpel
syncarpous
35
3 parts of the carpel
style, stigma, ovary
36
uniovulate
1 ovule
37
multi-ovulate
1+ ovules
38
Anatropous ovule definition
the micropyle is bent down
| adjacent to funicle
39
Micropyle
the narrow opening at the apex of the ovule
40
Chalaza
basal part of the ovule.
41
Integuments
protective layers
42
Nucellus
consists of a mass of parenchymatous cells
43
Hilum
point of attachment of the ovule with the funicle
44
Funicle
a small structure that connects the ovule to the placenta.
45
Embryo sac
multicellular structure embedded in the nucellus
46
placenta
the surface of the carpel
47
angiosperm uses ____ & _____ for seeed dispersal
biotic and abiotic agents
48
Pollination
transfer of pollen grain from the anther to the stigma
49
gametes are
non-motile
| produced at different sites
50
Self-pollination definition
pollination that occurs between flowers of the same plant
51
Self-pollination results in
inbreeding or selfing
52
Cross-pollination
pollination that occurs between flowers of the different plant
53
Types of pollination
Autogamy
Geitonogamy
Xenogamy
54
Autogamy
- a bisexual flower is pollinated by its own grain
| - offsprings - genetically similar
55
Geitonogamy
- transfer of pollen grain from one flower to a different flower from the same plant
- includes pollinating agent but can't bring genetic variation, only for ecological significance
56
Xenogamy
- transfer of pollen grain from one flower to a different flower on a different plant of the same species
- using pollinating agents
57
xenogamy types
abiotic
| biotic
58
```
Abiotic type
(inconspicuous
without fragrance
small
light in weight)
```
1) Wind (anemophily)
2) Water (hydrophily)
a) Hypohydrophily
b) Epihydrophily
59
Wind
anemophily
60
Water
hydrophily
61
anemophily
```
colourless
dry
stigma is feathery
pollen-large quantities.
stamen has long filament, veratile anther
stamen and stigma exposed to current
```
62
hydrophily
unwettable
63
Hypohydrophily
below surface of water
PG heavier than water, sinks, gets caught by stigma of female flower
PG are long, without exine
64
Epihydrophily
on surface of water
female flowers reaxh surface temporarily while male flowers float on water
PG specific gravity = water
65
Biotic agent
living organisms
66
Pollination by insects
Entomophily
67
Entomophily
flowers- large showy, bright, sweet odour
stigma - rough (mucilaginous secretion)
PG - spiny, pollen kit
68
Pollination by birds
ornithophily
69
ornithophily
flowers- large showy, bright and profuse, sweet nectar
| PG - spiny, sticky
70
Pollination by bats
chiropteryphily
71
chiropteryphily
several kilometers
flowers- dull colored, abundant nectar
PG - large amount
72
Outbreeding device
discourage self-pollination
| evolution
73
Outbreeding device
```
unisexuality
dichogamy
prepotency
heterostyly
herkogamy
self-incompatibility
```
74
unisexuality
the plant has either a male flower or a female flower
aka dioecism
e.g. maize or papaya
75
dichogamy
anther and stigma matures at a different stage in bisexual flower
protandry - androecium before gynoecium
protogyny- gynoecium before androecium
e.g. sunflower and gloriosa
76
prepotency
a pollen grain of other flowers germinate faster than the pollen of the same flower
e.g. apple
77
heterostyly
stigma and anther at a different level
| prevent pollen from reaching the stigma
78
herkogamy
natural, physical barrier present
79
self-incompatibility
genetic mechanism
| self-pollination not possible
80
Endosperm
triploid primary endosperm nucleus divides repeatedly mitotically to form nutritive tissue
81
What leads to the formation of endosperm?
formation of the endosperm nucleus triggers cell division
82
Type of endosperm on basis of mode of development
Nuclear
Cellular
Helobial
83
Nuclear type
PEN divides repeatedly without wall formation
vacuole pushes nuclei to periphery
wall develops; multicellular endosperm is formed
84
Cellular type
division of PEN immediately followed by wall formation
85
Heloboal type
division of PEN; followed by a transverse wall
which divides cell unequally; 2 cells formed
cells divide; walls formed
86
chalazal cell
smaller
87
micropylar cell
bigger
88
Parthenocarpy coined by
Noll (1902)
89
Parthenocarpy definition
fruit develops without fertilization
90
the unfertilized ovary produces auxin
enlarges ovary to fruit
| and fruit is seedless
91
Polyembryony definition
development of more than one embryo inside the seed
92
Polyembryony noticed by
Leeuwenhoek
93
Polyembryony =
multiple seedlings
94
Polyembryony results from
differentiation and development of various maternal and zygotic tissue associated with ovule of seed
95
Polyembryony true or false
embryo rises from the same embryo sac or different embryo sac in the same ovule
96
Adventive Polyembryony
the embryo develops directly from the diploid cell of the nucellus or integuments
97
Cleavage Polyembryony
proembryo divides into many units
| each unit becomes an embryo
98
Polyembryony advantages
increases chances of survival of new plants
| great in horticulture
