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Biology (NCERT) - Class XII > XII Chap 2 Sexual Reprod Flowering Plants > Flashcards

XII Chap 2 Sexual Reprod Flowering Plants Flashcards

1
Q

All flowering plants engage in sexual reproduction. T or F?

A

True

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2
Q

Angiosperms only engage in asexual reproduction. T or F?

A

False, they’re flowering plants => only engage in sexual reproduction

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3
Q

Define floriculture

A

branch of horticulture;
multi-billion dollar industry;
ornamental flowers and plant cultivation

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4
Q

What are the parts of the flower? (looking for 7 parts)

A

Ovary, sepal, stigma, style, anther, filament and petals

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5
Q

Floral primadorium?

A

Formation of little buds at end of stems from which flowers will develop

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6
Q

Inflorescence bears ________ and then flowers

A

floral buds

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7
Q

Male reproductive structure in plant is called _______?

Female?

A

Androecium;

Gynoecium

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8
Q

Two parts of the stamen?

A

Anther and filament

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9
Q

What is the filament?

A

Long and slender stalk;

Proximal end attached to the thalamus or petal

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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

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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

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12
Q

4 wall layers of microsporangia?

A

epidermis (outer most), endothecium, middle layers, tapetum (inner most)

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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

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14
Q

2 features of tapetum?

A

bi/multi-nucleate and dense cytoplasm

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15
Q

What is sporogenous tissue?

A

group of compact, homogenous cells;
diploid cells;
occupies center of microsporangium when anther is young

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16
Q

Microsporogenesis?

A

sporogenous tissue forms into microspores (tetrad) from a pollen mother cell (PMC) through meiosis

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17
Q

Sporogenous tissue consists of haploid or diploid cells?

Microspores?

A

Sporogenous tissue - Diploid

Microspores - Haploid

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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

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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
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20
Q

What is the size of a pollen grain?

A

25-50 micrometer in diameter

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21
Q

What is the general shape, color and texture of a pollen grain?

A

Spherical, yellowish and powdery

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22
Q

Pollen grain is the male gamete. True or False?

A

False, it’s the male gametophyte

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23
Q

Pollen has __-layered walls: _____-

A

2-layered

  1. Exine
  2. Intine
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24
Q

Exine?

A

Hard, outer layer;
Made of sporopollenin;
Many patterns and designs on it;
Indestructible by temperature, alkali, acid or enzyme;

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25
Q

What is the unique quality of sporopollenin?

A

cannot be destroyed; no enzyme found yet that can degrade it

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26
Q

Exine has pores where sporopllenin is absent. True or False?

A

True, called “germ pores”

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27
Q

What are germ pores?

A

Prominent apertures on the exine where sporopollenin is absent

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28
Q

What is the intine?

A

Thin, continuous layer;

made of cellulose and pectin

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29
Q

The cytoplasm of a young pollen grain is unbound and free. True or False?

A

False, surrounded by plasma membrane

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30
Q

Pollen grains mature into how many cells?

A

2 cells

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31
Q

What are the 2 cells in a mature pollen grain?

A

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

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32
Q

60% of angiosperms shed pollen at the 3-cell stage. True or False?

A

False.

40% do.

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33
Q

In 40% of angiosperms. the generative cell divides meiotically into 2 male gametes before shedding. T or F?

A

False. Mitotically.

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34
Q

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?

A

True

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35
Q

What effect do pollen grains have on humans?

A

allergies and bronchial ailments / respiratory disorders

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36
Q

_________ came into India with imported wheat as a contaminant that now causes pollen allergy

A

Parthenium - carrot grass

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37
Q

Pollen is consumed by athletes and race horses as it is rich in nutrients. T or F?

A

True

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38
Q

How long are pollen grains viable and what factors affect viability?

A

30 minutes to months;

factors: based on specific grain, temperature and humidity

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39
Q

How does one increase pollen viability to years?

A

store in liquid nitrogen (-196° C), pollen banks

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40
Q

Examples of pollen grains with short viability (30 mins)

A

Cereals - rice (paddy) and wheat

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41
Q

Examples of pollen grains with long viability (in months)

A

Rosaceae, Leguminoseae, Solanaceae

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42
Q

Where is the pistil located?

Another name for pistil?

A

In the gynoceium (female reproductive part)

aka carpel

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43
Q

Monocarpellary v Multicarpellary

A

Monocarpellary - single pistil

Multicarpellary - many pistils

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44
Q

Syncarpous vs apocarpous?

A 
Syncarpous = fused multicarpellary; 
Apocarpous = free multicarpellary
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45
Q

Example of multicarpellary, apocarpous ?

A

Michelia

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46
Q

Example of multicarpellary, syncarpous ?

A

Papaver

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47
Q

What are the 3 parts of the pistil?

A

Stigma, style and ovary

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48
Q

What is inside the ovary?

A

Cavity called locule (ovarian cavity) with placenta and megasporangia (ovules)

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49
Q

Another name for ovules?

A

Megasporangia

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50
Q

There is only one ovule in every ovary. T or F?

A

False, can be many (e.g. papaya)

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51
Q

One ovule plants?

A

Wheat, paddy, mango

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52
Q

Multi-ovule plants?

A

Watermelon, papaya, orchids

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53
Q

Ovule is attached to the _________

A

placenta

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54
Q

What is the point of attachment of the ovule called?

A

hilum

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55
Q

What is the funicle?

A

Stalk with which the ovule is attached to the placenta in the ovary

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56
Q

Integument?

A

Protective envelope of the ovule

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57
Q

Ovules may have 1 or 2 integuments. T or F?

A

True, in case of 2 - inner & outer

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58
Q

Integuments enclose the ovule entirely as a protective envelope. T or F?

A

False, they encircle it except at tip where there is a micropyle (small opening)

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59
Q

What is the nucellus?

A

Mass of diploid cells inclosed within integument; abundant with food reserve and contains the female gametophyte (i.e. embryo sac)

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60
Q

Micropyle lies at the basal end and chalaza lies at the other. T or F?

A

False, chalaza at the basal end, micropyle at the tip

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61
Q

Female gametophyte is called the ________

A

embryo sac

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62
Q

Ovules generally have only single embryo sac from a megaspore. T or F?

A

True

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63
Q

Define megasporogenesis

A

formation of megaspores from the MMC (mother cell) in micropylar region of nucellus

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64
Q

MMC undergoes meiotic division to product 4 megaspores. T or F?

A

True

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65
Q

In most flowering plants, 1 megaspore is functional and 3 are generate. T or F?

A

True

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66
Q

What happens to the functional megaspore?

A

Develops into embryo sac

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67
Q

What is monosporic development?

A

When SINGLE megaspore develops into the embryo sac

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68
Q

Describe steps in process of formation of embryo sac

A

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

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69
Q

Why are the mitotic divisions in formation of embryo sac called “free-nuclear”?

A

Not followed immediately by a cell wall formation (cytokinesis)

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70
Q

Embryo does not have cell walls since the mitosis divisions are “free-nuclear”. T or F?

A

False, cell wall forms just AFTER the mitosis reactions which leads to embryo sac forming

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71
Q

What are the 3 parts of the embryo sac?

A

Egg apparatus, Antipodals and Central Cell

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72
Q

Egg apparatus is at the chalazal end and antipodals at the micropylar. T or F?

A

False; reverse (egg at micropylar; antipodals at chalazal)

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73
Q

Egg apparatus has ____ cells; antipodals has _____ cells and central cell has _____

A

3, 3, 1

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74
Q

Egg apparatus has ____ nuclei; antipodals has _____ nuclei and central cell has _____ nuclei

A

3, 3, 2

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75
Q

Embryo sac is 8-celled and 7-nucleate. T or F?

A

False, reverse. 8-nucleate and 7-celled

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76
Q

What does egg apparatus consist of?

A

3 cells, 3 nuclei;
2 synergids and 1 egg;
Synergids have special cellular thickening called filliform apparatus which guide pollen tube into synergid

77
Q

What is the filiform apparatus?

A

Cellular thickening of the synergid (finger-like projections) that guides pollen tubes into the synergid

78
Q

What is in the central cell after the embryo sac is formed?

A

2 “polar” nuclei

79
Q

Describe pollination

A

Transfer of pollen grains shed from the anther to the stigma of the pistil

80
Q

Male and female gametes in flowering plants are motile. T or F?

A

False, they’re non-motile

81
Q

What are the 3 kinds of pollination and how do they differ?

A

Autogamy; Geitonogamy and Xenogamy
Autogamy - same flower / same plant
Geitonogamy - different flower / same plant
Xenogamy - different flower / different plant

82
Q

Which is the only type of pollination that brings about genetic variation?

83
Q

Is geitonogamy (same plant pollination) considered as cross-pollination?

A

Yes because they use agents that pollinate from one flower to another (even if on the same plant)

84
Q

Autogamy and geitonogamy both do not involve genetical variation. T or F?

85
Q

Chasmogamous vs cleistogamous flowers?

A

Chasmo - open and expose anthers; requires synchrony (often doesn’t happen)
Cleisto - never open, invariably autonomous

86
Q

Cleistogamous flowers do not require pollinators. T or F?

A

True, assured seed set

87
Q

Complete autogamy never happens in chasmogamous flowers. T or F?

A

False, can happen => but it’s rare because requires synchrony and to avoid in-breeding

88
Q

Two types of pollinators?

A 
Biotic agents (animals);
Abiotic agents (wind and water)
89
Q

What are the most common pollinating agents?

A

Animals, and among them bees

90
Q

Most common ABIOTIC pollinator?

91
Q

Abiotic pollination is a chance occurrence. T or F?

92
Q

Describe the conditions of wind pollination

A
  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
Q

Examples of wind pollinating plants

A

Corn cob

Grasses

94
Q

Describe the conditions of water pollinating plants

A
  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
Q

How does Vallisneria pollinate?

A

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
Q

How does Zostera pollinate?

A

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
Q

Most aquatic plants pollinate via wind or insects. T or F?

98
Q

Water lily and water hyacinth pollinate via water. T or F?

A

False, they’re above the surface of water and pollinated by wind or insects

99
Q

Wind and water pollinating flowers are not color nor do they release nectar. Why?

A

Don’t need to attract animals/insects

100
Q

Hydrilla is pollinated by wind or water?

101
Q

What are the animal pollinating agents?

A

Bess, butterflies, beetles, wasps, ants, moths bats, hummingbirds, sunbirds

Less common:
lemurs, arboreal rodents, garden / gecko lizards

102
Q

Flowers are often adapted for a specific species of animal pollinators. T or F?

103
Q

Difference between flowers when pollinated by wind vs. animals?

A

Wind - no fragrant / nectar / colorful petals;
pollen is non-sticky;

Animals - fragrant / nectar / colorful petals;
pollen is sticky;

104
Q

When flowers are small how does the plant ensure pollination by animals?

A

Many clustered together to be noticeable and promise of rewards

105
Q

What are the rewards for biotic agents?

A

Nectar,
Pollen,
Safe spaces to lay eggs

106
Q

_____ (plant) and ______ (pollinator) cannot complete their life cycles on their own.

A

Yucca and moth

107
Q

Amorphophallus is among the smallest flower pollinated by biotic agents. T or F?

A

False, flower itself is 6-feet tall - safe place for pollinators to lay eggs

108
Q

What are the plant outbreeding devices?

A
  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
Q

Self-incompatibility is a _______ kind of mechanism.

110
Q

Which outbreeding mechanisms prevent geitonogamy?

A

Unisexual flowers;

Sometimes self-incompatibility

111
Q

What are the outbreeding devices that prevent autogamy?

A

All of them

Pollen and stigma receptivity not synced;
Anther and stigma in different positions;
Self-incompatibility;
Unisexual flowers

112
Q

Describe pollen-pistil interaction (acceptance)

A

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
Q

Describe pollen-pistil interaction (rejection)

A

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
Q

What is the commercial significant of pollen-pistil interaction?

A

Artificial hybridization, crop improvement

115
Q

What are the 2 aspects of artificial hybridisation?

A

Emasculation - remove anther using forceps
Bagging - cover with butter paper until stigma receptive

Once stigma receptive => dust desired pollen grain and then rebag

116
Q

Emasculating unisexual female flowers needs to be done BEFORE dehiscence of anther. T or F?

A

False, female flowers have no anthers => don’t require emasculation

117
Q

What is double fertilization

A

ONE gamete fuses with egg cell to form zygote (syngamy), then embryo
ONE gamete fuses with central cell to form endosperm (triple fusion)

118
Q

Gymnosperms and angiosperms exhibit double fertilization. T or F?

A

False, only angiosperms (flowering plants)

119
Q

Describe syngamy in a flowering plant

A

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
Q

Describe triple fusion during fertilization in a flowering plant

A

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
Q

After fertilization, zygote develops into _______ and PEC into ______

A

False, zygote -> embryo

PEC -> endosperm

122
Q

What re the 3 post-fertilization events?

A
  1. Development of endosperm and embryo
  2. Maturation of ovule into seed
  3. Maturation of ovary into fruit
123
Q

Which develops first - endosperm OR embryo and why?

A

Endosperm to provide sufficient nutrition to embryo during its development

124
Q

Zygote divides only after certain amount of endosperm is produced. T or F?

A

True, to ensure sufficient nutrition for the embryo

125
Q

Describe endosperm development?

A

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
Q

Tender coconut is a great example of endosperm. Elaborate?

A

Coconut water = free-nuclear endosperm

White kernel/flesh = cellular endosperm

127
Q

What could endosperm look like at the end of the embryo and seed development?

A

Completely consumed by embryo (peas, groundnut, beans)
OR completed consumed in seed germination
OR persists in mature seed (castor, coconut)

128
Q

Embryo develops at chalazal or micropylar end?

A

Micropylar where the zygote also is

129
Q

Early stages of embryogeny are different in monocots and dicots. True or False?

A

False, they’re similar

130
Q

Differentiate between dicot & monocot embryogeny

A

dicot:
2 cotyledons

monocot:
1 cotelydon (called scutellum in grasses)
coleorrhiza

131
Q

Describe the shapes the zygote goes through in dicot seeds

A

Zygote -> proembryo -> globular -> heart -> mature

132
Q

Describe embyrogeny in dicot seed

A

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
Q

Describe embryogeny in monot seed

A

(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
Q

_________ is the final product of sexual reproduction

135
Q

Seed is nothing but a fertilized ovule. True or False?

136
Q

Seeds develop from ovules, after which the fruit develops from the ovary. True or False?

A

False, they develop simultaneously

137
Q

3 parts of a seed?

A 
Seed coat(s)
Cotelydons
Embryo axis
138
Q

Describe cotyledons in a seed

A

Thick, swollen - food reserves

e.g. legumes

139
Q

Non-albuminous vs. albuminous (w/ examples)

A

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
Q

Perisperm?

A

residual of nucellus that persists in seed

e.g. black pepper, beet

141
Q

Describe how the different parts of flower transform in seed/fruit development

A

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
Q

As seed matures, what happens to water content and metabolism?

A

Water content reduces. Only 10-15% of seed is moisture by mass.

General metabolic activity slows down

143
Q

Dormancy?

A

State of inactivity for embryo;

unfavorable conditions for germination

144
Q

What are the conditions required for germination?

A

Adequate moisture, oxygen and the right temperature (LIGHT IS NOT REQUIRED)

145
Q

Pericarp?

A

Wall of fruit that comes from the wall of the overy

146
Q

2 types of fruits

A

Fleshy & dry (groundnut, mustard)

147
Q

False vs. true fruits?

A

False - includes thalamus e.g. apple, strawberry and cashew

True - JUST ovary - most fruits fall into this category

148
Q

Parthenocarpic fruits?

A

Fruits that develop without fertilization e.g. banana

149
Q

Parthenocarpy can be induced using hormones and results in the fruit having artificial seeds. T or F?

A

False, can be induced with hormones but is seedless e.g. banana

150
Q

What are the advantages of seed formation?

A
  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
Q

_________ is the basis of our agriculture.

Options: Seeds; Artificial Hybridization; Pollination by bees

152
Q

What helps store seeds for long periods for agriculture?

A

Dormancy and dehydration

153
Q

What is the viability of a seed?

A

Mostly several years, in some species just few months; in some species 100s or even 1000s of years

154
Q

Example of the oldest known seed

A

10,000 years of dormancy;
Lupinus articus;
Discovered in Arctic Tundra

155
Q

Recently, we’ve found a seed that has lived for 2000 years in dormancy. Which one is it and where was it found?

A 
Date palm (Phoenix dactylifera); 
found in archaeological excavation of King Herod's palace near the Dead Sea
156
Q

3 examples of fruits that have thousands of tiny seeds

A

Orchid fruits
Orobanche
Striga

157
Q

Orobance and Striga are parasitic species that produce a small number of seeds in their fruit. T or F?

A

False, large number of seeds

158
Q

Apoximis?

A

Seeds without fertilization

e.g. Asteraceae, grasses, Citrus, mango

159
Q

________ seed is a seed without fertilization

________ fruit is a fruit without fertilization

A

Apomictic seed;

Parthenocarpic fruit

160
Q

Apoximis is the result of a form of sexual reproduction since it involves the formation of a seed. T or F?

A

False, it’s a form of asexual reprod that mirrors sexual reprod

161
Q

What are the different ways to produce apomictic fruits?

A
  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
Q

What is polyembryony and where do we see it occur?

A

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
Q

Mango and citrus are examples of apoximis where the diploid egg cell produces an embryo without reduction division or fertilization. T or F?

A

False, definition of diploid cell apoximis is accurate but this is an example of nucellar apoximis

164
Q

Once a hybrid seed is developed we never have to worry about producing it again for agriculture. T or F?

A

Hybrid seeds have to be produced every year

165
Q

Once sown, a hybrid seed tends to the natural separation of the species as progeny separates. T or F?

166
Q

Hybridization is a one-time process that has made reproducing those specific species of plants extremely cheap. T or F?

A

False, it’s expensive because it has to be done every year

167
Q

Why is a lot of research underway into apoximis?

A

Because it can make hybridization and crop production much cheaper

168
Q

__________ are the seat of sexual reproduction in angiosperms

169
Q

The central tissue in an ovule is nucellus in which the ______ differentiates

A

archesporium

170
Q

Angiosperms exhibit double fertilisation two fusion events occur in each embryo sac. T or F?

A

True, syngamy and triple fusion

171
Q

Seed coat is aka ______

172
Q

Integument and testa are made of living cells. T or F?

A

False, testa are made of dead cells

173
Q

Why is zygote dormant for sometime in a fertilised ovule?

A

Waiting for enough endosperm to form, so that endosperm can provide sufficient nutrition

174
Q

What is the role of tapetum in pollen-grain wall formation?

A
  • provide nutrition to maturing pollen grains
  • amino acides, enzymes and hormones
  • forms exine
175
Q

What is dichogamy?

A

Production of M and F reproductive organs at different times in plants to prevent self-pollination

176
Q

Cells of which of the layers of the anther wall are multinucleated due to to endomitosis?
epidermis - endomecium - middle layer - tapetum

177
Q

Pollen grain lose their viability in 30 minutes in ________

178
Q

Ovule of an angiosperm is technically equivalent to:

megasporangium - megaspore mother cell - megaspore - megasporophyll

A

megasporangium

179
Q

Flowers which have a single ovule in the ovary and are packed into inflorescence are usually pollinated by:
bat - wind - bee - water

180
Q

Non-albuminous seed is produced in:

pea - maize - castor - wheat

181
Q

Nucellar polyembrony is reported in:

Gossypium - Brassica - Citrus - Triticum

182
Q

Apomictic embryos in citrus arise from:

synergids - maternal sporophytic tissue in ovule - antipodal cells - diploid egg

A

maternal sporophytic tissue in ovule

183
Q

Unisexuality of flowers prevents which type(s) of pollination (autogamy, geitonogamy, xenogamy)

A

autogamy but not geitonogamy

184
Q 
Male gametophyte in angiosperms produce: 
one sperm + vegetative cell
two sperms + vegetative cell
one sperm + 2 vegetative cells
3 sperms
A

two sperms + vegetative cell

185
Q 
Seed of castor is:
non-endospermic, exalbuminous
endospermic albuminous
endospermic exalbuminous
non-endospermic albuminous
A

endospermic albuminous

186
Q

Sporopollenin can withstand high pressures. T or F?

A

False, high temperatures

187
Q

Sporopollenin is one of the most resistant organic OR inorganic materials known?

188
Q

In angiosperms, embryo sac is ___-sporic with _____ sequential mitotic divisions

Biology (NCERT) - Class XII (18 decks)

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