Stamen, Microsporangium and Pollen Grain

Question 1

constituents of stamen

Answer 1

long and slender stalk called filament and bilobed anther.

Question 2

what is the proximal end of the filament connected to

Answer 2

thalamus

Question 3

an anther is

Answer 3

bilobed and dithecous

Question 4

what separates the thecas

Answer 4

a longitudinal groove

Question 5

how many microsporangia in each lobe

Answer 5

2 in each(total 4)

Question 6

the microsporangia develop further into

Answer 6

pollen sacs containing pollen grains

Question 7

structure of microsporangia

Answer 7

epidermis, endothecium, middle layers and tapetum

Question 8

what do the first three layers of microsporangia do

Answer 8

protect the anther and aid in the dehiscence of the anther to release the pollen.

Question 9

Function of tapetum

Answer 9

to nourish the developing pollen grains

Question 10

how do tapetal cells become bi-nucleate

Answer 10

no cytokinesis after karyokinesis

Question 11

what is at the center of each microsporangium

Answer 11

sporogenous tissue

Question 12

How are microspore tetrads formed

Answer 12

from meiotic division of sporogenous tissue

Question 13

What is microsporogenesis

Answer 13

formation of microspores from PMC(pollen mother cell)

Question 14

outer layer of a pollen grain- name and what is it made of

Answer 14

exine and it is made of sporopollenin

Question 15

why is sporopollenin known as the most resistant organic material

Answer 15

it can withstand high temperatures, strong acids and alkali. no enzyme has been discovered that can degrade sporopollenin.

Question 16

where is sporopollenin absent in the exine

Answer 16

germ pores

Question 17

function of germ pores

Answer 17

formation of pollen tube and helps in release of male gamete

Question 18

inner wall of a pollen grain and what is it made of

Answer 18

intine and it is made of cellulose and pectin

Question 19

what is formed when a pollen grain matures

Answer 19

a vegetative cell which is a large cell that has abundant food reserve. and a generative cell which floats in the cytoplasm and divides mitotically to form 2 male gametes.

Question 20

what cause pollen allergy in india

Answer 20

parthenium or carrot grass

Question 21

when do pollen grains lose their viability in rice and wheat

Answer 21

within 30 mins

Question 22

when do leguminoseae, Solanoceae and Rosaceae pollen grains lose their viability

Answer 22

within months

Question 23

at what temperature are pollen grains stored and in what

Answer 23

-196C in liquid nitrogen