Plant Reproduction Flashcards
Parts of Stamen ?
Filament - long and slender stalk
anther - bilobed structure
The proximal end of filament is attached to ?
Thalamus or petal
Angiosperm anther is _________ with each love having _________ they are dithecous
Bilobed
Two theca
What separates theca ?
Longitudinal groove
Microsporangia ?
Located in anther
They are 4
Located at corners
Microsporangia further develops into which stage
Pollen sacs
Microsporangium
Laters?
Epidermis
Endothecium
Middle layer
These layers perform protection and dehiscence of anther to release the pollen
Tapetum
Nourish the pollen grain
Posses dense cytoplasm
And have more than one nucleus
Sporogenous tissue ?
Occupies centre of microsporangium
Homogeneous cells
Microsporogenesis ?
Sporogenous tissue undergo meiotic divisions and form 4 microspore tetrad
And each give rise to potential pollen or pollen mother cell by the process microsporogenesis
And after anther mature and dehydrate
Microspore develop into pollen grains
Pollen grain size?
25-50 micrometer Diameter
layers of pollen grain ?
exine - sporopollenin
resitance to temperature acids and Alkali
It also has germ pores where this layer is absent
they can be preserved as fossil
intine - cellulose and pectin
two cells when pollen grains get mature ?
vegetative cells - bigger
Contains food reserves and large irregular nucleus
generative cells - Small
float in cytoplasm spindle shaped
% of angiosperms pollen grain shed at 2 celled stage
60
Allergies caused by pollen grains
?
Asthma and bronchitis
Parthenium causes pollen allergy
Pollen grains used as ?
Food supplement
Tablets and syrups
Increase performance of athletes and race horses
