XII Chap 2 Sexual Reprod Flowering Plants Flashcards
(188 cards)
1
Q
All flowering plants engage in sexual reproduction. T or F?
A
True
2
Q
Angiosperms only engage in asexual reproduction. T or F?
A
False, they’re flowering plants => only engage in sexual reproduction
3
Q
Define floriculture
A
branch of horticulture;
multi-billion dollar industry;
ornamental flowers and plant cultivation
4
Q
What are the parts of the flower? (looking for 7 parts)
A
Ovary, sepal, stigma, style, anther, filament and petals
5
Q
Floral primadorium?
A
Formation of little buds at end of stems from which flowers will develop
6
Q
Inflorescence bears ________ and then flowers
A
floral buds
7
Q
Male reproductive structure in plant is called _______?
Female?
A
Androecium;
Gynoecium
8
Q
Two parts of the stamen?
A
Anther and filament
9
Q
What is the filament?
A
Long and slender stalk;
Proximal end attached to the thalamus or petal
10
Q
Describe anther and its components
A
Terminal end of the filament;
bilobed;
each lob has 2 theca (sheath or covering) separated by longitudinal grooves;
4-sided or tetragonal microsporangia
11
Q
What is microsporangium?
A
structure where development of pollen takes place;
4 of them in four corners of anther;
extends longitudinally thru the length of the anther;
becomes pollen sacs;
packed with thousands of pollen grains
12
Q
4 wall layers of microsporangia?
A
epidermis (outer most), endothecium, middle layers, tapetum (inner most)
13
Q
What are the functions of the 4 walls of the microsporangia?
A
outer and next 2 perform function of protection and splitting open;
inner most - tapetum - nourishes
14
Q
2 features of tapetum?
A
bi/multi-nucleate and dense cytoplasm
15
Q
What is sporogenous tissue?
A
group of compact, homogenous cells;
diploid cells;
occupies center of microsporangium when anther is young
16
Q
Microsporogenesis?
A
sporogenous tissue forms into microspores (tetrad) from a pollen mother cell (PMC) through meiosis
17
Q
Sporogenous tissue consists of haploid or diploid cells?
Microspores?
A
Sporogenous tissue - Diploid
Microspores - Haploid
18
Q
Each cell of the sporogenous tissue is capable of microsporogenesis i.e. each is a potential mother cell or pollen grain. True or False?
A
True
19
Q
What are the events leading up to pollen grains release?
A
Anther matures / dehydrates
- > micropores separate
- > develop into pollen grains
- > dehiscence of anther
- > pollen grains released
20
Q
What is the size of a pollen grain?
A
25-50 micrometer in diameter
21
Q
What is the general shape, color and texture of a pollen grain?
A
Spherical, yellowish and powdery
22
Q
Pollen grain is the male gamete. True or False?
A
False, it’s the male gametophyte
23
Q
Pollen has __-layered walls: _____-
A
2-layered
- Exine
- Intine
24
Q
Exine?
A
Hard, outer layer;
Made of sporopollenin;
Many patterns and designs on it;
Indestructible by temperature, alkali, acid or enzyme;
25
What is the unique quality of sporopollenin?
cannot be destroyed; no enzyme found yet that can degrade it
26
Exine has pores where sporopllenin is absent. True or False?
True, called "germ pores"
27
What are germ pores?
Prominent apertures on the exine where sporopollenin is absent
28
What is the intine?
Thin, continuous layer;
| made of cellulose and pectin
29
The cytoplasm of a young pollen grain is unbound and free. True or False?
False, surrounded by plasma membrane
30
Pollen grains mature into how many cells?
2 cells
31
What are the 2 cells in a mature pollen grain?
VEGETATIVE - bigger; food reserve; large, irregular nucleus; formation of pollen tube
GENERATIVE - small; floats in cytoplasm of vegetative cell; asymmetrical spindle shape, dense cytoplasm; has nucleus; formation of male gamete
32
60% of angiosperms shed pollen at the 3-cell stage. True or False?
False.
| 40% do.
33
In 40% of angiosperms. the generative cell divides meiotically into 2 male gametes before shedding. T or F?
False. Mitotically.
34
In 40% of angiosperms the generative cell divides into 2 male gametes before shedding and this is called the 3-celled stage. T or F?
True
35
What effect do pollen grains have on humans?
allergies and bronchial ailments / respiratory disorders
36
_________ came into India with imported wheat as a contaminant that now causes pollen allergy
Parthenium - carrot grass
37
Pollen is consumed by athletes and race horses as it is rich in nutrients. T or F?
True
38
How long are pollen grains viable and what factors affect viability?
30 minutes to months;
| factors: based on specific grain, temperature and humidity
39
How does one increase pollen viability to years?
store in liquid nitrogen (-196° C), pollen banks
40
Examples of pollen grains with short viability (30 mins)
Cereals - rice (paddy) and wheat
41
Examples of pollen grains with long viability (in months)
Rosaceae, Leguminoseae, Solanaceae
42
Where is the pistil located?
| Another name for pistil?
In the gynoceium (female reproductive part)
| aka carpel
43
Monocarpellary v Multicarpellary
Monocarpellary - single pistil
| Multicarpellary - many pistils
44
Syncarpous vs apocarpous?
```
Syncarpous = fused multicarpellary;
Apocarpous = free multicarpellary
```
45
Example of multicarpellary, apocarpous ?
Michelia
46
Example of multicarpellary, syncarpous ?
Papaver
47
What are the 3 parts of the pistil?
Stigma, style and ovary
48
What is inside the ovary?
Cavity called locule (ovarian cavity) with placenta and megasporangia (ovules)
49
Another name for ovules?
Megasporangia
50
There is only one ovule in every ovary. T or F?
False, can be many (e.g. papaya)
51
One ovule plants?
Wheat, paddy, mango
52
Multi-ovule plants?
Watermelon, papaya, orchids
53
Ovule is attached to the _________
placenta
54
What is the point of attachment of the ovule called?
hilum
55
What is the funicle?
Stalk with which the ovule is attached to the placenta in the ovary
56
Integument?
Protective envelope of the ovule
57
Ovules may have 1 or 2 integuments. T or F?
True, in case of 2 - inner & outer
58
Integuments enclose the ovule entirely as a protective envelope. T or F?
False, they encircle it except at tip where there is a micropyle (small opening)
59
What is the nucellus?
Mass of diploid cells inclosed within integument; abundant with food reserve and contains the female gametophyte (i.e. embryo sac)
60
Micropyle lies at the basal end and chalaza lies at the other. T or F?
False, chalaza at the basal end, micropyle at the tip
61
Female gametophyte is called the ________
embryo sac
62
Ovules generally have only single embryo sac from a megaspore. T or F?
True
63
Define megasporogenesis
formation of megaspores from the MMC (mother cell) in micropylar region of nucellus
64
MMC undergoes meiotic division to product 4 megaspores. T or F?
True
65
In most flowering plants, 1 megaspore is functional and 3 are generate. T or F?
True
66
What happens to the functional megaspore?
Develops into embryo sac
67
What is monosporic development?
When SINGLE megaspore develops into the embryo sac
68
Describe steps in process of formation of embryo sac
Nucleus of functional megaspore divides (mitosis) into 2-nucleate sac; both nuclei move to opposite poles and under mitosis again -> 4-nucleate -> mitosis -> 8-nucleate -> cell wall forms -> embryo sac developed
69
Why are the mitotic divisions in formation of embryo sac called "free-nuclear"?
Not followed immediately by a cell wall formation (cytokinesis)
70
Embryo does not have cell walls since the mitosis divisions are "free-nuclear". T or F?
False, cell wall forms just AFTER the mitosis reactions which leads to embryo sac forming
71
What are the 3 parts of the embryo sac?
Egg apparatus, Antipodals and Central Cell
72
Egg apparatus is at the chalazal end and antipodals at the micropylar. T or F?
False; reverse (egg at micropylar; antipodals at chalazal)
73
Egg apparatus has ____ cells; antipodals has _____ cells and central cell has _____
3, 3, 1
74
Egg apparatus has ____ nuclei; antipodals has _____ nuclei and central cell has _____ nuclei
3, 3, 2
75
Embryo sac is 8-celled and 7-nucleate. T or F?
False, reverse. 8-nucleate and 7-celled
76
What does egg apparatus consist of?
3 cells, 3 nuclei;
2 synergids and 1 egg;
Synergids have special cellular thickening called filliform apparatus which guide pollen tube into synergid
77
What is the filiform apparatus?
Cellular thickening of the synergid (finger-like projections) that guides pollen tubes into the synergid
78
What is in the central cell after the embryo sac is formed?
2 "polar" nuclei
79
Describe pollination
Transfer of pollen grains shed from the anther to the stigma of the pistil
80
Male and female gametes in flowering plants are motile. T or F?
False, they're non-motile
81
What are the 3 kinds of pollination and how do they differ?
Autogamy; Geitonogamy and Xenogamy
Autogamy - same flower / same plant
Geitonogamy - different flower / same plant
Xenogamy - different flower / different plant
82
Which is the only type of pollination that brings about genetic variation?
Xenogamy
83
Is geitonogamy (same plant pollination) considered as cross-pollination?
Yes because they use agents that pollinate from one flower to another (even if on the same plant)
84
Autogamy and geitonogamy both do not involve genetical variation. T or F?
True
85
Chasmogamous vs cleistogamous flowers?
Chasmo - open and expose anthers; requires synchrony (often doesn't happen)
Cleisto - never open, invariably autonomous
86
Cleistogamous flowers do not require pollinators. T or F?
True, assured seed set
87
Complete autogamy never happens in chasmogamous flowers. T or F?
False, can happen => but it's rare because requires synchrony and to avoid in-breeding
88
Two types of pollinators?
```
Biotic agents (animals);
Abiotic agents (wind and water)
```
89
What are the most common pollinating agents?
Animals, and among them bees
90
Most common ABIOTIC pollinator?
Wind
91
Abiotic pollination is a chance occurrence. T or F?
True
92
Describe the conditions of wind pollination
1. light and non-sticky grains
2. well-exposed stamens
3. large, feathery stigma
4. often single ovule in ovary
5. many flowers packed into inflorescence
93
Examples of wind pollinating plants
Corn cob
| Grasses
94
Describe the conditions of water pollinating plants
1. limited, only 30 genera in total
2. few different ways, on surface or within surface carried by water currents (e.g. Vallisneria)
3. if WITHIN water, pollen-grains are LONG, ribbon-like and covered in mucilagous covering to protect from wetness (e.g. seagrasses)
95
How does Vallisneria pollinate?
Female flower on a long stalk that reaches surface;
Male flower/pollen grains released on the surface;
Carried by water currents eventually reaches the female flower
96
How does Zostera pollinate?
Female is in water;
male pollen grains are long, ribbon-like and carried in the water passively, covered in mucilagous covering to protect from wetness until they reach the female flowers
97
Most aquatic plants pollinate via wind or insects. T or F?
True
98
Water lily and water hyacinth pollinate via water. T or F?
False, they're above the surface of water and pollinated by wind or insects
99
Wind and water pollinating flowers are not color nor do they release nectar. Why?
Don't need to attract animals/insects
100
Hydrilla is pollinated by wind or water?
Water
101
What are the animal pollinating agents?
Bess, butterflies, beetles, wasps, ants, moths bats, hummingbirds, sunbirds
Less common:
lemurs, arboreal rodents, garden / gecko lizards
102
Flowers are often adapted for a specific species of animal pollinators. T or F?
True
103
Difference between flowers when pollinated by wind vs. animals?
Wind - no fragrant / nectar / colorful petals;
pollen is non-sticky;
Animals - fragrant / nectar / colorful petals;
pollen is sticky;
104
When flowers are small how does the plant ensure pollination by animals?
Many clustered together to be noticeable and promise of rewards
105
What are the rewards for biotic agents?
Nectar,
Pollen,
Safe spaces to lay eggs
106
_____ (plant) and ______ (pollinator) cannot complete their life cycles on their own.
Yucca and moth
107
Amorphophallus is among the smallest flower pollinated by biotic agents. T or F?
False, flower itself is 6-feet tall - safe place for pollinators to lay eggs
108
What are the plant outbreeding devices?
1. Pollen & stigma receptivity not synchronized
2. Anther and stigma placement away from each other
3. Self-incompatibility (rejection of pollen grain - germination or tube growth)
4. Unisexual flowers e.g. papaya
109
Self-incompatibility is a _______ kind of mechanism.
Genetic
110
Which outbreeding mechanisms prevent geitonogamy?
Unisexual flowers;
| Sometimes self-incompatibility
111
What are the outbreeding devices that prevent autogamy?
All of them
Pollen and stigma receptivity not synced;
Anther and stigma in different positions;
Self-incompatibility;
Unisexual flowers
112
Describe pollen-pistil interaction (acceptance)
Continuous dialogue involving chemical components of pistil and pollen grain
If pollen accepted, tubes grow down to ovary
(If 2-celled, generative cell divides into 2 male gametes during tube growth)
Tube enters ovule through micropyle
Enters one of the synergids through filiform apparatus
113
Describe pollen-pistil interaction (rejection)
Continuous dialogue involving chemical components of pistil and pollen grain
If wrong pollen grain (wrong species OR self-incompatible);
Pistil inhibits germination / tube growth
114
What is the commercial significant of pollen-pistil interaction?
Artificial hybridization, crop improvement
115
What are the 2 aspects of artificial hybridisation?
Emasculation - remove anther using forceps
Bagging - cover with butter paper until stigma receptive
Once stigma receptive => dust *desired* pollen grain and then rebag
116
Emasculating unisexual female flowers needs to be done BEFORE dehiscence of anther. T or F?
False, female flowers have no anthers => don't require emasculation
117
What is double fertilization
ONE gamete fuses with egg cell to form zygote (syngamy), then embryo
ONE gamete fuses with central cell to form endosperm (triple fusion)
118
Gymnosperms and angiosperms exhibit double fertilization. T or F?
False, only angiosperms (flowering plants)
119
Describe syngamy in a flowering plant
Pollen tube releases 2 male gametes in synergid's cytoplasm, one of them goes to the egg cell and fuses with the nucleus producing a diploid cell (zygote)
120
Describe triple fusion during fertilization in a flowering plant
Pollen tube releases 2 male gametes into synergid's cytoplasm; one goes to the polar nuclei in central cell and fuses to produce a triploid primary endosperm nucleus (PEN) make the central cell a primary endosperm cell (PEC)
121
After fertilization, zygote develops into _______ and PEC into ______
False, zygote -> embryo
| PEC -> endosperm
122
What re the 3 post-fertilization events?
1. Development of endosperm and embryo
2. Maturation of ovule into seed
3. Maturation of ovary into fruit
123
Which develops first - endosperm OR embryo and why?
Endosperm to provide sufficient nutrition to embryo during its development
124
Zygote divides only after certain amount of endosperm is produced. T or F?
True, to ensure sufficient nutrition for the embryo
125
Describe endosperm development?
PEC divides repeatedly into triploid endosperm tissue (reserve food materials); this is free-nuclei division => free-nuclear endosperm)
after then cell wall formation => cellular endosperm
126
Tender coconut is a great example of endosperm. Elaborate?
Coconut water = free-nuclear endosperm
| White kernel/flesh = cellular endosperm
127
What could endosperm look like at the end of the embryo and seed development?
Completely consumed by embryo (peas, groundnut, beans)
OR completed consumed in seed germination
OR persists in mature seed (castor, coconut)
128
Embryo develops at chalazal or micropylar end?
Micropylar where the zygote also is
129
Early stages of embryogeny are different in monocots and dicots. True or False?
False, they're similar
130
Differentiate between dicot & monocot embryogeny
dicot:
2 cotyledons
monocot:
1 cotelydon (called scutellum in grasses)
coleorrhiza
131
Describe the shapes the zygote goes through in dicot seeds
Zygote -> proembryo -> globular -> heart -> mature
132
Describe embyrogeny in dicot seed
Zygote -> proembryo -> globular -> heart -> mature;
embryonal axis + 2 cotyledons;
above cotyledon => epicotyl which ends in plumule or stem tip
below cotyledon => hypocotyl which ends in radical or root tip covered in root cap
133
Describe embryogeny in monot seed
(In grass)
1 Cotyledon aka scutellum on one side of the embryonal axis;
epicotyl: shoot apex + leaf primadoria enclosed in *coleoptile*
radical & root cap in 'undifferentiated sheath' called 'coleorrhiza'
134
_________ is the final product of sexual reproduction
Seed
135
Seed is nothing but a fertilized ovule. True or False?
True
136
Seeds develop from ovules, after which the fruit develops from the ovary. True or False?
False, they develop simultaneously
137
3 parts of a seed?
```
Seed coat(s)
Cotelydons
Embryo axis
```
138
Describe cotyledons in a seed
Thick, swollen - food reserves
| e.g. legumes
139
Non-albuminous vs. albuminous (w/ examples)
Non-albuminous - no residual endosperm, completely consumed in embryo dev. (e.g. pea, groundnut, beans)
Albuminous - retains part of the endosperm (e.g. wheat, maize, barley, castor)
140
Perisperm?
residual of nucellus that persists in seed
| e.g. black pepper, beet
141
Describe how the different parts of flower transform in seed/fruit development
Ovule -> seed; ovary -> fruit
Integuments -> hard, protective coats
Micropyle -> remains as small pore on seed coat for oxygen and water entry during germination
Wall of ovary -> wall of fruit
Endosperm -> may or may not be consumed
Thalamus -> becomes part of fruit IF false fruit
In SOME cases, nucellus -> perisperm
Other parts of flower degenerate and fall off
142
As seed matures, what happens to water content and metabolism?
Water content reduces. Only 10-15% of seed is moisture by mass.
General metabolic activity slows down
143
Dormancy?
State of inactivity for embryo;
| unfavorable conditions for germination
144
What are the conditions required for germination?
Adequate moisture, oxygen and the right temperature (LIGHT IS NOT REQUIRED)
145
Pericarp?
Wall of fruit that comes from the wall of the overy
146
2 types of fruits
Fleshy & dry (groundnut, mustard)
147
False vs. true fruits?
False - includes thalamus e.g. apple, strawberry and cashew
| True - JUST ovary - most fruits fall into this category
148
Parthenocarpic fruits?
Fruits that develop without fertilization e.g. banana
149
Parthenocarpy can be induced using hormones and results in the fruit having artificial seeds. T or F?
False, can be induced with hormones but is seedless e.g. banana
150
What are the advantages of seed formation?
1. Processes like pollination and fertilization are independent of water
2. Better adaptive strategies for dispersal and colonizing new areas
3. Sufficient food reserves before plant is capable of photosynthesis
4. Seed coat is a protective layer
5. Formed due to sexual reproduction hence new genetic variations
151
_________ is the basis of our agriculture.
| Options: Seeds; Artificial Hybridization; Pollination by bees
Seeds
152
What helps store seeds for long periods for agriculture?
Dormancy and dehydration
153
What is the viability of a seed?
Mostly several years, in some species just few months; in some species 100s or even 1000s of years
154
Example of the oldest known seed
10,000 years of dormancy;
Lupinus articus;
Discovered in Arctic Tundra
155
Recently, we've found a seed that has lived for 2000 years in dormancy. Which one is it and where was it found?
```
Date palm (Phoenix dactylifera);
found in archaeological excavation of King Herod's palace near the Dead Sea
```
156
3 examples of fruits that have thousands of tiny seeds
Orchid fruits
Orobanche
Striga
157
Orobance and Striga are parasitic species that produce a small number of seeds in their fruit. T or F?
False, large number of seeds
158
Apoximis?
Seeds without fertilization
| e.g. Asteraceae, grasses, Citrus, mango
159
________ seed is a seed without fertilization
| ________ fruit is a fruit without fertilization
Apomictic seed;
| Parthenocarpic fruit
160
Apoximis is the result of a form of sexual reproduction since it involves the formation of a seed. T or F?
False, it's a form of asexual reprod that mirrors sexual reprod
161
What are the different ways to produce apomictic fruits?
1. Diploid egg cell without reduction division produces embryo without fertilization
2. Nucellar cells start to divide and protrude into the embryo sac and develop into embryo
162
What is polyembryony and where do we see it occur?
When one ovule has many embryos
We see it in apoximis of the type where nucellar cells start to divide and protrude into embryo sac
e.g. Mango, citrus
163
Mango and citrus are examples of apoximis where the diploid egg cell produces an embryo without reduction division or fertilization. T or F?
False, definition of diploid cell apoximis is accurate but this is an example of nucellar apoximis
164
Once a hybrid seed is developed we never have to worry about producing it again for agriculture. T or F?
Hybrid seeds have to be produced every year
165
Once sown, a hybrid seed tends to the natural separation of the species as progeny separates. T or F?
True
166
Hybridization is a one-time process that has made reproducing those specific species of plants extremely cheap. T or F?
False, it's expensive because it has to be done every year
167
Why is a lot of research underway into apoximis?
Because it can make hybridization and crop production much cheaper
168
__________ are the seat of sexual reproduction in angiosperms
Flowers
169
The central tissue in an ovule is nucellus in which the ______ differentiates
archesporium
170
Angiosperms exhibit double fertilisation two fusion events occur in each embryo sac. T or F?
True, syngamy and triple fusion
171
Seed coat is aka ______
testa
172
Integument and testa are made of living cells. T or F?
False, testa are made of dead cells
173
Why is zygote dormant for sometime in a fertilised ovule?
Waiting for enough endosperm to form, so that endosperm can provide sufficient nutrition
174
What is the role of tapetum in pollen-grain wall formation?
- provide nutrition to maturing pollen grains
- amino acides, enzymes and hormones
- forms exine
175
What is dichogamy?
Production of M and F reproductive organs at different times in plants to prevent self-pollination
176
Cells of which of the layers of the anther wall are multinucleated due to to endomitosis?
epidermis - endomecium - middle layer - tapetum
tapetum
177
Pollen grain lose their viability in 30 minutes in ________
wheat
178
Ovule of an angiosperm is technically equivalent to:
| megasporangium - megaspore mother cell - megaspore - megasporophyll
megasporangium
179
Flowers which have a single ovule in the ovary and are packed into inflorescence are usually pollinated by:
bat - wind - bee - water
wind
180
Non-albuminous seed is produced in:
| pea - maize - castor - wheat
pea
181
Nucellar polyembrony is reported in:
| Gossypium - Brassica - Citrus - Triticum
Citrus
182
Apomictic embryos in citrus arise from:
| synergids - maternal sporophytic tissue in ovule - antipodal cells - diploid egg
maternal sporophytic tissue in ovule
183
Unisexuality of flowers prevents which type(s) of pollination (autogamy, geitonogamy, xenogamy)
autogamy but not geitonogamy
184
```
Male gametophyte in angiosperms produce:
one sperm + vegetative cell
two sperms + vegetative cell
one sperm + 2 vegetative cells
3 sperms
```
two sperms + vegetative cell
185
```
Seed of castor is:
non-endospermic, exalbuminous
endospermic albuminous
endospermic exalbuminous
non-endospermic albuminous
```
endospermic albuminous
186
Sporopollenin can withstand high pressures. T or F?
False, high temperatures
187
Sporopollenin is one of the most resistant organic OR inorganic materials known?
organic
188
In angiosperms, embryo sac is ___-sporic with _____ sequential mitotic divisions
mono, 3
