Stamen, Microsporangium and Pollen Grain
Call Kai
Learn
Practice Test
Spaced Repetition
Match
Flashcards
Knowt Play1/57
There's no tags or description
Looks like no tags are added yet.
Name | Mastery | Learn | Test | Matching | Spaced | Call with Kai |
|---|
No analytics yet
Send a link to your students to track their progress
58 Terms
filment + anther =
stamen
A typical angiosperm anther is
bilobed
each lobe of anther have two theca, i.e., they are
dithecous
In anther longitudinal groove runs lengthwise _________ the theca.
separating
anther is a four-sided (tetragonal) structure consisting of four ________ located at the corners, two in each lobe.
microsporangia
The microsporangia develop further and become _______ _____.
pollen sacs
pollen sacs are packed with ______ _____.
pollen grains
microsporangium is surrounded by _____ wall layers.
four layers
which of the following perform function of protection and helping dehiscence of anther ?
epidermis, endothecium, middle layers and the tapetum.
epidermis, endothecium, middle layers.
which of the following perform function of nourishment the developing pollen grains?
epidermis, endothecium, middle layers and the tapetum.
only tapetum
When the anther is young, a group of compactly arranged homogenous cells called the ___________ ______ occupies the centre of each microsporangium.
sporogenous tissue.
the cells of the sporogenous tissue undergo meiotic divisions to form _____________ _________.
microspore tetrads.
each cell of the sporogenous tissue act as
pollen mother cell (PMC)
The process of formation of microspores from a pollen mother cell (PMC) through meiosis is called _________________.
microsporogenesis
As the anthers mature and dehydrate, the microspores dissociate from each other and develop _________________.
into pollen grains
Pollen grains are generally spherical measuring about
25-50 micrometers in diameter.
The hard outer layer of pollen grain is called the _______.
exine.
exine is made up of __________ which is extremely resistant to heat , acid and alkalis.
sporopollenin
No ______ can degrade sporopollenin.
enzyme
exine is made up of sporopollenin which is extremely resistant to ______ , ______ and _______.
heat , acid and alkalis.
Pollen grain exine has prominent apertures called ____ ____ where sporopollenin is absent.
germ pores
Pollen grains are well-preserved as _____ because of the presence of sporopollenin.
fossils
The inner wall of the pollen grain is called the _____.
intine.
Intine is a thin and continuous layer made up of
cellulose and pectin.
Intine lies ______ the exine.
beneath
The cytoplasm of pollen grain is surrounded by a _________ _____________.
plasma membrane.
hen the pollen grain is mature it contains two cells, the vegetative cell and ___________ ___.
generative cell
vegetative cell is larger in
Size
vegetative cell has abundant ____ __________.
food reserves.
The vegetative cell is bigger, has abundant food reserve and a large irregularly shaped ________.
nucleus
generative cell is small and floats in the cytoplasm of ___ ____________ ____.
the vegetative cell.
vegetative cell is _____ ______ with dense cytoplasm and a nucleus.
spindle shaped
In over 60 per cent of angiosperms, pollen grains are shed at this _____ ________.
2-celled stage
in over 40 per cent of angiosperms , the generative cell divides mitotically to give rise to the two male gametes before pollen grains are shed
(3-celled stage)
Pollen allergy