Chapter 1 : Sexual Reproduction in Flowering Plants Flashcards
(124 cards)
1
Q
Panchanan MAheshwari born in ____________ 1904 in jaipur (Rajasthan)
A
November
2
Q
Panchanan Maheshwari is recognized as the Father of Indian _______________ due to his monumental contributions towards establishing embryology as a distinct discipline of study in India. He is renowned for establishing the technique of “test-tube fertilization of angiosperms” which allowed the creation of new hybrid plants that could not previously be crossbred naturally.
A
Embryology
3
Q
All flowering plants show ________________ reproduction
A
Sexual reproduction
4
Q
To a biologist , flowers are morphological and embryological marvels and the sites of ____________________
A
sexual reproduction
5
Q
In the flower the male and Female reproductive structures, the ________________ and the __________________ differentiate and develop.
A
Androecium
gynoecium
6
Q
The androecium consists of a whorl of Stamens representing the ________________ organ and the gynoecium represents the _______________ organ
A
Male reproductive organ
female reproductive organ
7
Q
The Two parts of a typical Stamen- the long and slender stalk called the ______________, and the terminal generally bilobed structure called the _______________
A
Filament
Anther
8
Q
A typical angiosperm anther is Bilobed with each lobe having two Theca i.e, they are _____________
A
dithecous
9
Q
The Anther is four-sided(tetragonal) structure consisting of four __________________ located at the corners, two in each lobe
A
microsporangia
10
Q
The microsporangia develop further and become _______________
A
Pollen sacs
11
Q
Microsporangium is generally surrounded by four wall layers- the epidermis, _________________ , middle layers and the ______________. It nourishes the developing pollen grains
A
endothecium
tapetum
Note:- Cells of tapetum possess dense cytoplasm and generally have more than one nucleus.
12
Q
When the anther is young, a group of compactly arranged homogenous cells called the ________________ occupies the center of each microsporangium
A
sporogenous tissue
13
Q
As the anther develops, the cells of the sporogenous tissue undergo _____________ divisions to form microspore _____________
A
meiotic division
microspore tetrads
14
Q
Each cell of the sporogenous tissue is capable of giving rise to a ___________________
A
microspore tetrads
15
Q
The process of formation of microspores from a pollen mother cell (PMC) through meiosis is called _______________
A
microsporogenesis
16
Q
As the anthers mature and dehydrate, the microspore tetrad dissociate from each other and develop into ________________
A
pollen grains
17
Q
The pollen grains represent the _________ gametophytes
A
Male gametophyte
18
Q
Pollen grains are generally spherical measuring about ________ micrometers in diameter.
A
25- 50
19
Q
Pollen grains has a prominent two-layered wall, The hard outer layer called the ______________ is made up of _______________ which is one of the most resistant organic material known.
A
Exine
Sporopollenin (one of the most resistant organic material it can tolerate high temperatures and strong acids and alkali)
20
Q
No enzyme that degrades ______________ is so far known.
A
Sporopollenin
21
Q
Pollen grain exine has prominent apertures called _____________ pores where sporopollenin is absent
A
germ pores
22
Q
The inner wall of pollen grain is called the _____________
A
intine
23
Q
Intine is a thin and continuous layer made up of ___________ and ______________
A
cellulose
pectin*
24
Q
When the pollen grain is mature it contains two cells, the ______________ and ___________________
A
vegetative cell
generative cell
25
The **vegetative cell** is **bigger**, has abundant food reserve and a large irregularly shaped **nucleus**. The _______________ is **small** and floats in the cytoplasm of the _________________ cell
**generative cell**
**vegetative cell**
26
In over **60 %** of **Angiosperms**, pollen grains are shed at this **2-celled stage** (i.e generative cell and vegetative cell stage). In remaining species, the ______________ cell divides **mitotically** to give rise to the two male gametes before pollen grains are shed (3-celled stage)
**generative cell**
27
**pollen grains** of many species cause **severe allergies** and bronchial afflictions in some people often leading to chronic respiratory disorders- ___________ and __________ etc
**Asthma**
**Bronchitis**
28
____________ or **Carrot grass** that came into **India** as a contaminant with **imported wheat**, has become ubiquitous in occurrence and causes ***pollen allergy**
**Parthenium**
29
**Pollen** consumption has been claimed to increase the performance of ___________ and ______________
**athletes**
**race horses**
30
In some cereals such as **rice** and **wheat**, pollen grains lose viability within _________ minutes of their release.
**Thirty (30)***
31
In some members of **Rosaceae , Leguminosae and Solanaceae** pollen grains maintain viability for ______________
**months**
32
It is possible to store **pollen grains** of a large number of species for years in ________________
**Liquid nitrogen** (-1960C)
33
The ______________ represents the female **reproductive part** of the flower.
**Gynoecium***
34
A **pistil** consists of the ___________ , _____________ and _____________
**stigma**
**style**
**ovary**
35
The **gynoecium** may consist of a **single pistil** (________________)
**monocarpellary**
36
The **gynoecium** may consist of more than one **pistil**(________________)
**multicarpellary**
37
When there are more than one, pistils may be fused together called _____________ or may be **free** _________________
**syncarpous**
**apocarpous**
Note:- Syncarpous pentacarpellary pistil in **Hibiscus**
Syncarpous multicarpellary pistil in **Papaver**
Apocarpous multicarpellary pistil in **Michelia**
38
The ____________ serves as a landing platform for **pollen grains**
**stigma**
39
The basal bulged part of the pistil is the ____________. Inside the ovary is the **ovarian cavity** (Locule)
**Ovary**
40
The ___________ is located inside the ovarian cavity
**Placenta**
41
Arising from the **placenta** are the __________________, commonly called ______________
**Megasporangia**
**Ovules**
42
The number of ovules in an ovary may be _________ as in (**wheat,paddy, mango**)
and __________ in (**papaya, water melon, orchids**)
**one**
**many**
43
The **ovule** is a small structure attached to the placenta by means of a stalk called _______________
**funicle**
44
The body of the ovule fuses with **funicle** in the region called ___________
**hilum**
45
Each ovule has **one or two** protective envelops called ___________
**integuments**
46
**Integuments** encircle the nucellus except at the top where a small opening called the ___________
**micropyle**
47
Opposite the micropylar end , is the _________ representing the basal part of the ovule
**Chalaza**
48
Enclosed within the **integuments** is a mass of cells called the ______________
**nucellus**
49
Located in the nucellus is the _____________ or **Female gametophyte**
**embryo sac**
50
An ovule generally has a single **embryo sac** formed from a ______________
**megaspore**
51
The process of formation of megaspores from the **megaspore mother cell** is called _______________
**megasporogenesis**
52
**Ovule** generally differentiate a single ___________________ in the micropylar region of the nucellus. It is a large cell containing dense cytoplasm and a prominent nucleus.
**megaspore mother cell (MMC)**
53
The **MMC** ***(megaspore mother cell)*** undergoes meiotic division. Meiosis results in the production of ___________ **megaspores**
**Four**
54
In a majority of flowering plants, one of the **megaspores** is functional while other ____________ degenerate.
**three**
55
Only the **functional megaspore** develops into the female gametophyte (__________________)
**embryo sac**
56
This method of **embryo sac** formation from a **single** megaspore is termed __________________ development.
**monosporic**
57
The nucleus of the **functional** megaspore divides **mitotically** to form two nuclei which move to the opposite poles, forming the __________ nucleate embryo sac.
**2- nucleate**
58
Two more sequential **mitotic** nuclear divisions result in the formation of the _______ nucleate and later the ________ nucleate stages of the embryo sac
**4-nucleate**
**8-nucleate**
Note:- These mitotic divisions are strictly **free nuclear**, that is, nuclear divisions are not followed immediately by cell wall formation.
59
__________ of the **eight** nuclei are surrounded by cell walls and organised into cells; the remaining _________ nuclei, called **polar nuclei** are situated below the **egg apparatus** in the large **central cell**.
**Six**
**two**
60
**Three** cells are grouped together at the **micropylar** end and constitute the _____________________
**egg apparatus**
61
The **egg apparatus**, in turn, consists of **two** ______________ and **one** ____________
**synergids**
**egg cell**
62
The synergids have special cellular thickenings at the **micropylar tip** called _________________ apparatus, which play an important role in guiding the pollen tubes into the synergid.
**filiform apparatus**
63
**Three** cells are at the **chalazal end** and are called the _________________
**antipodals**
64
The large **central cell** has _______ polar nuclei.
**two**
65
A typical angiosperm **embryo sac**, at maturity, though __________ nucleate is ________ celled
**8-nucleate**
**7-celled**
66
Transfer of **pollen grains** to the **Stigma** of a **pistil** is termed ____________________
**Pollination**
67
Depending on the **source of pollen**, pollination can be divided into three parts:-
1.______________
2._____________
3._____________
**Autogamy** (pollination within same flower)
**Geitonogamy**(Pollination from **different flower of Same plant**)
**Xenogamy** (Pollination from **different plant**)
68
Some plants such as **Viola(common pansy)** , ***Oxalis***, and ***Commelina** produce two types of of flowers:-
1._______________
2.______________
**Chasmogamous** (Open flower exposed anther and stigma)
**Cleistogamous** (flowers which do not open at all)
Note:- remember the plant names, which have both types of flowers
69
**Geitonogamy** is genetically similar to **autogamy** since the **pollen grains** come from the ____________ plant.
**same plant**
70
______________ is the only type of **pollination** which during pollination brings **genetically** different types of pollen grains to to the **Stigma**
**Xenogamy**
71
Plants use two **abiotic** (___________ and _____________) and one **biotic** (_______________) agents to achieve pollination.
**wind** and **water** (abiotic)
**animal** (biotic)
72
**Wind pollination** is quite common in _______________
**grasses**
73
Pollination by **water** is quite rare in flowering plants and a _______ genera, mostly **monocotyledons**
**30**
74
water is a regular mode of transport for the **male gametes** among the lower plants groups such as **algae**, **bryophytes** and __________________
**pteridophytes**
75
**Water pollinated** plants are ________________ and _________________ which grow in **fresh water** and several marine sea-grasses such as _________________
**Vallisneria**
**Hydrilla**
**Zostera**
76
**Water hyacinth** and **waterlily** the flowers emerge above the level of water and are pollinated by ______________ or _____________ as in most of the land plants
**insects**
**wind**
77
Both **wind and water** pollinated flowers are not very **colorful** and do not produce _________________
**nectar**
78
Majority of ____________ pollinated flowers are **large, colorful, fragrant** and rich in **nectar**
**Insect**
79
80
A species of **moth** and the plant ________ where both species- moth and the plant cannot complete their life cycles without each other.
***Yucca***
81
Continued **self-pollination** result in _____________ depression.
**Inbreeding depression**
82
If both male and female flowers are present on the same plant is called ______________
**Monoecious**
ex:- castor and maize
Note:- It prevents **autogamy** but not **geitonogamy**.
83
In **papaya**, male and female flowers are present on different plants called ___________, that is each plant is either male or female
**dioecious**
Note:- This condition prevents both **autogamy** and **geitonogamy**
84
**Pollen tube** grows through the tissues of the stigma and style and reaches the _____________
**Ovary**
85
In some plants, pollen grains are shed at ________ celled condition (a vegetative cell and a generative cell). In such plants, the _______________ cell divides and forms the **two** male gametes **during the growth of pollen tube** in the stigma.
**two**
**generative cell**
86
In the **three-celled** condition, pollen tubes carry the two male gametes **from the beginning**. after reaching the ovary, enters the **ovule** through the micropyle and then enters one of the **synergids** through the ____________ apparatus.
**filiform apparatus**
87
A **breeder** is interested in crossing different species and often genera to combine desirable characters to produce **commercially** _____________ varieties.
**superior**
88
___________ **hybridisation** is one of the major approaches of crop improvement programme.
**Artificial hybridisation**
89
Removal of **anthers** from the flower bud before the anther dehisces using a pair of forceps. This step is referred to as ____________________
**emasculation**
90
**Emasculated** flowers have to be covered with bag of suitable size, generally made up of ____________ paper, to prevent contamination of its stigma with unwanted pollen. This process is called _____________
**Butter paper**
**Bagging**
91
After entering one of the synergids, the **pollen tube** releases the **two male gametes** int the cytoplasm of the ______________
**synergid**
92
One of the male gamete moves towards the **egg cell** and fuses with its nucleus thus completing the _____________. This results in the formation of a **diploid cell**, the ________________
**Syngamy**
**Zygote** (2n)
93
The other male gamete moves towards the **two polar nuclei** located in the central cell and fuses with them to produce a **triploid** _____________________ (**PEN**) . As this involves the fusion of **three haploid** nuclei it is termed ______________
**Primary endosperm nucleus** (3n)
**triple fusion**
94
Since two types of fusions, **syngamy** and **triple fusion** take place in an embryo sac the phenomenon is termed ____________________
**double fertilisation**
95
The central cell after **triple fusion** becomes the **Primary endosperm cell (PEC)** and develops into the _________________ while the **zygote** develops into an _____________
**endosperm**
**embryo**
96
Following **double fertilisation**, events of endosperm and embryo development, maturation of **ovules into seeds** and **ovary into fruit**, are collectively termed __________________________
**post-fertilisation events**
97
The **primary endosperm cell** (PEC) divides repeatedly and forms a triploid _______________ tissue.
**endosperm**
98
Endosperm may either be completely consumed by the developing embryo before seed maturation
ex:- __________ , ___________, _____________
It may persist in the mature seed and be used up during seed germination
ex:- ___________ and _______________
**pea , groundnut , beans**
**castor and coconut**
99
**Embryo** develops at the _____________ end of the **embryo sac** where the **zygote** is situated.
**Micropylar end**
100
The early stage of **Embryo** development is known as __________ are similar in both **monocotyledons** and **dicotyledons**
**Embryogeny**
101
The **zygote** gives rise to the **Proembryo** and subsequently to the __________ , ____________ and _____________
**Globular**
**Heart-shaped**
**Mature embryo**
102
A typical **dicotyledons embryo** consists of and **embryonal axis** and two ___________________
**cotyledons**
103
The portion of **embryonal axis** above the level of cotyledons is the ______________ , which terminates with the **plumule** or **stem tip**
**epicotyl**
104
The cylindrical portion below the level of cotyledons is _____________ that terminates at its lower end in the **radicle** or **root tip**. The root tip is covered with a **root cap**.
**Hypocotyl**
105
Embryos of monocotyledons posses only one **cotyledon**, In the **grass family** the cotyledon is called ______________ that is situated towards one side of the embryonal axis.
**Scutellum**
106
At lower end, the **embryonal axis** has the **radical and root cap** enclosed in an undifferentiated sheath called _____________
**Coleorrhiza**
107
The portion of the **embryonal axis** above the level of attachment of **scutellum** is the epicotyl. **Epicotyl** has a shoot apex and a few leaf primordia enclosed in a hollow foliar structure called ________________
**Coleoptile**
108
In **angiosperms**, the **seed** is the final product of _____________ reproduction. It is often described as a **fertilised ovule**.
**Sexual reproduction**
109
A seed typically consists of **seed coat** , **cotyledon** and an _________________ axis
**embryo axis**
110
**Non** _______________ seeds have **no residual endosperm** as it is completely consumed during embryo development
eg:- **pea** and **groundnut**
**Non albuminous**
111
**Albuminous seeds** retain a part of _______________ as it is not completely used up during **embryo development**
eg:- **Wheat , maize , barley , castor**
**endosperm**
112
In some seeds such as **black pepper** and **beet**, remnants of **nucellus** are also persistent . This residual, persistent nucellus is the _______________
**perisperm**
113
As the seed matures, its water content is reduced and seeds become relatively dry ___________ percent moisture by **mass**. The general metabolic activity of the embryo slows down.
**10 - 15 %**
114
The embryo may enter a state of inactivity called ____________, or if favorable condition are available (adequate moisture, oxygen and suitable temperature) they geminate.
**dormancy**
115
As **ovule** mature into **seeds**, the **ovary** develops into a __________
**fruits**
116
The wall of **ovary** develops into the wall of **Fruit** called ________________
**pericarp**
117
In a few species such as **apple, strawberry, cashew** etc., the **thalamus** also contributes to fruit formation. Such fruits are called _______________
**False fruits**
118
Most fruits however develop only from the ovary and are called _____________
**true fruits**
119
In most of the species, fruits are the result of **fertilisation** , there are a few species in which fruits develop **without fertilisation**. Such fruits are called ___________________ fruits.
**Parthenocarpic fruits**
ex:- **banana**
Note:- Parthenocarpy can be induced through the application of **growth hormones** and such fruits are **seedless**
120
There are several records of very old yet **viable seeds**. The oldest is that of a **lupine**,***Lupinus arcticus** excavated from **Arctic Tundra**. The seed germinated and flowered after an estimated record of ____________ years of **dormancy**.
**10,000 years**
121
A recent record of **2000 years** old viable seed is of the ________ palm, ***Phoenix dactylifera** discovered during the archeological excavation at **King Herod's** place near the **Dead sea**
**Date palm** (Phoenix dactylifera)
122
In general seeds are the products of **fertilisation**, a few flowering plants such as some species of ***Asteraceae*** and **grasses**, have evolved a special mechanism, to produce seeds without fertilisation, called ______________
**Apomixis**
123
**Apomixis** is a form of ________________ reproduction that mimics **sexual reproduction**
**asexual reproduction**
124
Occurrence of **more than one embryo** in a seed is referred to as _____________
**polyembryony**
Note:- more often, as in many ***citrus*** and ***mango***
The diploid egg cell is formed without reduction division and develops into the embryo without fertilisation.
