Key Terms and its Meaning | Sexual Reproduction in Flowering Plants | Class-12 Biology


TermExplanation
MicrosporogenesisFormation of microspores from a PMC through meiosis
MegasporogenesisFormation of megaspores from the mega spore mother cell
Monosporic developmentEmbryo sac formation from a single megaspore
PollinationTransfer of pollen grains from anther to the stigma of a pistil
AutogamyTransfer of pollen grains from the anther to the stigma of the same flower.
GeitonogamyTransfer of pollen grains from the anther to the stigma of another flower of the same plant.
XenogamyTransfer of pollen grains from anther to the stigma of a different plant.
Artificial hybridisationCrossing different species to combine desirable characters to produce superior varieties.
EmasculationRemoval of anthers from flower bud before the anther dehisces.
BaggingCovering emasculated flowers with a bag to prevent contamination of its stigma with unwanted pollen.
SyngamyFusion of male and female gamete
Triple fusionFusion of three haploid nuclei
Double FertilisationTwo types of fusions syngamy and triple fusion that takes place in an embryo sac.
Post fertilization eventsEvents of endosperm ,embryo development ,maturation of ovule into seed, ovary into fruit.
Free –nuclear endospermThe stage of endosperm development wherein PEN undergoes successive nuclear divisions to give rise to free nuclei.
Dormancy of seedEmbryo enter a state of inactivity (Resting period of seed)
False fruitThalamus contributes to fruit formation
True fruitFruits develop from the ovary
Parthenocarpic fruitsFruits develop without fertilisation
ApomixisProduction of seeds without fertilisation of grasses
PolyembryonyMore than one embryo in a seed
FilamentLong slender stalk of stamen
AntherBilobed structure of stamen
DithecousTwo theca in each lobe
TapetumInnermost wall layer of microsporangia
Sporogenous tissueCompactly arranged homogenous cells in the centre of microsporangia.
Microspore tetradCluster of four microspores
Pollen grainsMale gametophyte
ExineHard outer layer of pollen grain
SporopolleninMost resistant organic material of exine
Germ poreApertures in pollen grain
IntineInner wall of the pollen grain
Generative cellCell floats in the cytoplasm of vegetative cell
MonocarpellarySingle pistil
MulticarpellaryMore than one pistil
SyncarpousFused pistils
ApocarpousFree pistils
StigmaLanding platform of pollen grains
StyleElongated slender part beneath the stigma
OvaryBasal bulged part of pistil
OvuleMegasporangia
FunicleStalk of ovule
HilumRegion ,the body of the ovule fuses with funicle
IntegumentsProtective envelopes of ovule
MicropyleSmall opening in the ovule
ChalazaBasal part of the ovule
Embryo sacFemale gametophyte
Egg apparatusThree cells at the micropylar end with two synergids and one egg cell.
AntipodalsThree cells at the chalazal end
Cleistogamous flowerFlowers which do not open at all
ZygoteDiploid cell resulting out of fertilisation
Primary endosperm cellCentral cell after triple fusion becomes PEC
EmbryogenyEmbryo development
EpicotylPortion of embryonal axis above the level of cotyledons
HypocotylPortion below the level of cotyledons
ScutellumCotyledon of grass family situated towards one side of embryonal axis.
ColeorrhizaUndifferentiated sheath that encloses radical and root cap
ColeoptileHollow foliar structure that encloses a shoot apex and a few leaf primordia.
Non-albuminous seed or ex-No residual endosperm as it is completely consumed during embryo development.
AlbuminousRetain a part of endosperm as it is not completely used up during embryo development.
PerispermResidual persistent nucellus
PericarpWall of the fruit

Post a Comment

0 Comments