UNIT VI – REPRODUCTION
CHAPTER : 2 SEXUAL REPRODUCTION IN FLOWERING PLANTS (KEY POINTS)
|
S.No |
Term |
Explanation |
|
1 |
Microsporogenesis |
Formation of microspores from a PMC through
meiosis |
|
2 |
Megasporogenesis |
Formation of megaspores from the mega spore mother cell |
|
3 |
Monosporic development |
Embryo sac formation from a single megaspore |
|
4 |
Pollination |
Transfer of pollen grains from anther to the stigma of a
pistil |
|
5 |
Auto gamy |
Transfer of pollen grains from the anther to the stigma of the same
flower |
|
6 |
Geitonogamy |
Transfer of pollen grains from the anther to the stigma of another flower
of the same plant |
|
7 |
Xenogamy |
Transfer of pollen grains from anther to the stigma of a different plant |
|
8 |
Artificial hybridisation |
Crossing different species to
combine desirable characters to produce superior varieties |
|
9 |
Emasculation |
Removal of anthers from flower bud before the
anther dehisces |
|
10 |
Bagging |
Covering
emasculated flowers with a bag to prevent contamination of its stigma with
unwanted pollen |
|
11 |
Syngamy |
Fusion of male and female gamete |
|
12 |
Triple
fusion |
Fusion of three haploid nuclei |
|
13 |
Double
Fertilisation |
Two types of fusions syngamy
and triple fusion that takes place in an embryo sac |
|
14 |
Post
fertilization events |
Events of endosperm ,embryo development ,maturation of ovule into seed,
ovary into fruit |
|
15 |
Free –nuclear
endosperm |
The stage
of endosperm development wherein PEN undergoes successive nuclear divisions
to give rise to free nuclei |
|
16 |
Dormancy of
seed |
Embryo enter a state of inactivity (Resting
period of seed) |
|
17 |
False fruit |
Thalamus
contributes to fruit formation |
|
18 |
True fruit |
Fruits develop
from the ovary |
|
19 |
Parthenocarpic fruits |
Fruits develop
without fertilisation |
|
20 |
Apomixis |
Production of
seeds without fertilization, in grasses |
|
21 |
Polyembryony |
More than one
embryo in a seed |
|
22 |
Filament |
Long slender
stalk of stamen |
|
23 |
Anther |
Bilobed structure of stamen |
|
24 |
Dithecous |
Two theca in each
lobe |
|
25 |
Tapetum |
Innermost wall layer of micro sporangia |
|
26 |
Sporogenous
tissue |
Compactly
arranged homogenous cells in the centre of microsporangia |
|
27 |
Microspore tetrad |
Cluster of four
microspores |
|
28 |
Pollen grains |
Male gametophyte |
|
29 |
Exine |
Hard outer layer of pollen grain |
|
30 |
Sporopollenin |
Most resistant organic material of exine |
|
31 |
Germ pore |
Apertures in pollen grain |
|
32 |
Intine |
Inner wall of the pollen grain |
|
33 |
Generative
cell |
Cell floats in the cytoplasm of vegetative
cell |
|
34 |
Monocarpellary |
Single pistil |
|
35 |
Multicarpellary |
More than one pistil |
|
36 |
Syncarpous |
Fused pistils |
|
37 |
Apocarpous |
Free pistils |
|
38 |
Stigma |
Landing platform of pollen grains |
|
39 |
Style |
Elongated slender part beneath the stigma |
|
40 |
Ovary |
Basal bulged part of pistil |
|
41 |
Ovule |
Megasporangia |
|
42 |
Funicle |
Stalk of ovule |
|
43 |
Hilum |
Region ,the body of the ovule fuses with
funicle |
|
44 |
Integuments |
Protective envelopes of ovule |
|
45 |
Micropyle |
Small opening in the ovule |
|
46 |
Chalaza |
Basal part of the ovule |
|
47 |
Embryo sac |
Female gametophyte
|
|
48 |
Egg
apparatus |
Three
cells at the micropylar end with two synergids and one egg cell |
|
49 |
Antipodals |
Three cells at the chalazal end |
|
50 |
Cleistogamous
flower |
Flowers which do not open at all |
|
51 |
Zygote |
Diploid cell resulting out of fertilisation |
|
52 |
Primary endosperm
cell |
Central cell after triple fusion becomes PEC |
|
53 |
Embryogeny |
Embryo development |
|
54 |
Epicotyl |
Portion of embryonal axis above the level of cotyledons |
|
55 |
Hypocotyl |
Portion of embrgonic axis below the level of
cotyledons |
|
56 |
Scutellum |
Cotyledon of grass family situated towards one
side of embryonal axis |
|
57 |
Coleorrhiza |
Undifferentiated sheath that encloses radical
and root cap |
|
58 |
Coleoptile |
Hollow foliar structure that encloses a shoot
apex and a few leaf primordia |
|
59 |
Non-albuminous seed or
ex-albuminous |
No residual endosperm as it is completely
consumed during embryo development |
|
60 |
Albuminous |
Retain a part of endosperm as it is not
completely used up during embryo development |
|
61 |
Perisperm |
Residual persistent nucellus |
|
62 |
Pericarp |
Wall of the fruit |