Active research is going on in many laboratories around the world to understand the genetics of apomixis. What is the purpose of such active research?
(1) Hybrid plants are directly formed by apomixis
(2) Apomixis is the method to produce seed without fertilization
(3) To transfer apomictic genes into hybrid varieties which will prevent loss of hybrid vigour with successive years
(4) Apomixis produces genetically different individuals
Pollen tube releases the two male gamete into the:
(1) One male gamete in cytoplasm of synergids and other in cytoplasm of central cell
(2) Both in cytoplasm of central cell
(3) Cytoplasm of Antipodal cell
(4) Both in cytoplasm of synergids
Read the statements and select option representing correct statements with respect to stamen.
A. The distal end of filament is attached to thalamus.
B. A typical anther is dithecous and bisporangiate.
C. Connective is sterile vasculated tissue.
D. Microsporangia develop further and become pollen sacs.
1. A & B 2. A & C
3. B & C 4. C & D
Outer three layers of anther wall perform the function of
(1) Nourishment
(2) Protection
(3) Dehiscence
(4) Both 2 & 3
The genetic mechanism, that prevents self pollen (from the same flower or other flowers of the same plant) from fertilising the ovules by inhibiting pollen germination or pollen tube growth in the pistil, is called as
1. Dioecy
2. Dichogamy
3. Monocliny
4. Self incompatibility
Plants pollinated by wind do not show
(1) Light and non-sticky pollen grains
(2) Well-exposed stamens
(3) Large-sized flowers
(4) Presence of single ovule in each ovary
Genetically and functionally self-pollination is cent percent ensured with seed formation even in the absence of pollinators by
Polygonum type embryo sac is
(1) Monosporic
(2) Seven celled with one largest binucleate cell
(3) Eight nucleated with 3 + 2 + 3 arrangement
(4) All are correct
Ovule generally differentiate a single _____ in the ______ region of the nucellus.
(1) Megaspore mother cell, micropylar
(2) Megaspore, micropylar
(3) Megaspore, mother cell, chalazal
(4) Primary
How many statement(s) is/are correct for pollen grains?
a. Parthenium is a cause of bronhial afflictions
b. Intine exhibits fascinating array of patterns and designs
c. Cytoplasm of pollen grain is surrounded by spermoderm
d. Generative cell is present when pollens are shed in 40 percent plants.
1. One 2. Two
3. Three 4. Four