🌿 Concept - Pollen Pistil Interaction 🌿
1. Pollen–pistil interaction mainly involves
A. Formation of pollen grains
B. Growth of pollen tube
C. Germination of ovule
D. Formation of embryo
Answer: B
Explanation: Pollen–pistil interaction refers to recognition, acceptance/rejection, and growth of pollen tube on pistil.
2. The compatible pollen grain on stigma
A. Bursts immediately
B. Fails to germinate
C. Germinates to form pollen tube
D. Forms embryo directly
Answer: C
Explanation: Compatible pollen germinates and forms a pollen tube for fertilization.
3. Incompatible pollen grain is
A. Accepted and nourished
B. Rejected by pistil
C. Always from same species
D. Always diploid
Answer: B
Explanation: Pistil has mechanisms to reject incompatible pollen.
4. The stigma surface is adapted for
A. Protection
B. Absorption of water
C. Pollen germination
D. Embryo formation
Answer: C
Explanation: Stigma provides suitable conditions for pollen hydration and germination.
5. Pollen tube enters ovule through
A. Chalaza
B. Funiculus
C. Micropyle
D. Integument
Answer: C
Explanation: Entry through micropyle is called porogamy (most common).
6. Recognition of compatible pollen occurs at
A. Ovary
B. Ovule
C. Stigma
D. Embryo sac
Answer: C
Explanation: Recognition happens at stigma surface.
7. The pollen tube grows through
A. Xylem
B. Phloem
C. Style tissue
D. Cortex
Answer: C
Explanation: Pollen tube grows through transmitting tissue of style.
8. Which chemical helps pollen tube growth?
A. Auxin
B. Gibberellin
C. Sugars and boron
D. Cytokinins
Answer: C
Explanation: Sugars and boron promote pollen tube growth.
9. Pollen tube carries
A. One male gamete
B. Two male gametes
C. One female gamete
D. Zygote
Answer: B
Explanation: Two male gametes are present in pollen tube.
10. In angiosperms, pollen grain is
A. Multicellular
B. 3-celled at shedding
C. 2-celled at shedding
D. Unicellular
Answer: C
Explanation: Usually 2-celled (vegetative + generative cell).
11. Which cell forms pollen tube?
A. Generative cell
B. Male gamete
C. Vegetative cell
D. Synergid
Answer: C
Explanation: Vegetative cell forms pollen tube.
12. Generative cell divides to form
A. Synergids
B. Two male gametes
C. Zygote
D. Endosperm
Answer: B
Explanation: It divides mitotically into two male gametes.
13. Self-incompatibility prevents
A. Cross-pollination
B. Self-pollination
C. Fertilization
D. Germination
Answer: B
Explanation: It prevents pollen from same plant/species.
14. Self-incompatibility is controlled by
A. Environment
B. Hormones
C. Genetic mechanism
D. Enzymes only
Answer: C
Explanation: It is genetically controlled.
15. Entry of pollen tube through chalaza is
A. Porogamy
B. Chalazogamy
C. Mesogamy
D. Autogamy
Answer: B
Explanation: Chalazogamy = entry through chalaza.
16. Entry through integuments is
A. Porogamy
B. Chalazogamy
C. Mesogamy
D. Xenogamy
Answer: C
Explanation: Mesogamy = entry through integuments.
17. Synergids help in
A. Endosperm formation
B. Attracting pollen tube
C. Nutrition to embryo
D. Protection of ovule
Answer: B
Explanation: Filiform apparatus guides pollen tube.
18. Filiform apparatus is present in
A. Egg cell
B. Antipodal cells
C. Synergids
D. Central cell
Answer: C
Explanation: It guides pollen tube entry.
19. Pollen tube releases male gametes into
A. Central cell
B. Synergid
C. Egg cell
D. Antipodal cell
Answer: B
Explanation: Pollen tube bursts in one synergid.
20. Pollen-pistil interaction ensures
A. Fertilization always
B. Species specificity
C. Seed dispersal
D. Germination of seed
Answer: B
Explanation: Prevents interspecific fertilization.
21. Which structure nourishes pollen tube?
A. Ovary
B. Style
C. Stigma
D. Ovule
Answer: B
Explanation: Transmitting tissue of style provides nutrition.
22. Incompatibility reaction can occur at
A. Stigma only
B. Style only
C. Ovary only
D. Any level of pistil
Answer: D
Explanation: Rejection may occur at stigma, style, or ovary.
23. Pollen tube growth is
A. Random
B. Chemotropic
C. Geotropic
D. Phototropic
Answer: B
Explanation: Guided by chemical signals.
24. A compatible pollen grain will
A. Shrink
B. Burst
C. Germinate
D. Degenerate
Answer: C
Explanation: Germination indicates compatibility.
25. Male gametes are formed by
A. Meiosis
B. Mitosis
C. Fusion
D. Reduction
Answer: B
Explanation: Generative cell divides mitotically.
26. Pollen tube is absent in
A. Gymnosperms
B. Angiosperms
C. Bryophytes
D. Both A and C
Answer: C
Explanation: Bryophytes lack pollen tube.
27. The stigma is usually
A. Dry or wet
B. Always dry
C. Always wet
D. Hard
Answer: A
Explanation: Can be dry or wet depending on species.
28. In dry stigma, pollen recognition is mediated by
A. Sugars
B. Lipids and proteins
C. Water
D. Hormones
Answer: B
Explanation: Protein–protein interaction helps recognition.
29. Pollen tube nucleus is
A. Haploid
B. Diploid
C. Triploid
D. Tetraploid
Answer: A
Explanation: Vegetative nucleus is haploid.
30. Pollen tube growth stops when
A. It reaches stigma
B. It reaches style
C. Male gametes are released
D. Endosperm forms
Answer: C
Explanation: Function completes after gamete release.
31. Which is NOT part of pollen-pistil interaction?
A. Recognition
B. Acceptance
C. Rejection
D. Seed dispersal
Answer: D
Explanation: Seed dispersal occurs after fertilization.
32. Self-incompatibility promotes
A. Inbreeding
B. Hybridization
C. Cross-pollination
D. Self-fertilization
Answer: C
Explanation: It encourages genetic diversity.
33. Pollen grains of same species but different plant are
A. Incompatible
B. Compatible
C. Always rejected
D. Sterile
Answer: B
Explanation: They are usually compatible.
34. Pollen tube enters embryo sac near
A. Antipodal cells
B. Central cell
C. Egg apparatus
D. Chalaza
Answer: C
Explanation: Egg apparatus = egg + synergids.
35. In pollen tube, the leading nucleus is
A. Male nucleus
B. Egg nucleus
C. Vegetative nucleus
D. Zygote nucleus
Answer: C
Explanation: Vegetative nucleus leads tube growth.
36. Pollen tube grows faster in
A. Incompatible pistil
B. Compatible pistil
C. Dry stigma
D. Damaged stigma
Answer: B
Explanation: Nutrients and signals are optimal.
37. The main role of pistil is
A. Seed formation
B. Pollination
C. Fertilization support
D. Photosynthesis
Answer: C
Explanation: Pistil supports fertilization process.
38. Pollen tube growth is essential for
A. Pollination
B. Double fertilization
C. Meiosis
D. Embryo sac formation
Answer: B
Explanation: Required to deliver male gametes.
39. Which hormone promotes pollen tube growth?
A. ABA
B. Ethylene
C. Auxin
D. Boron (not hormone)
Answer: D
Explanation: Boron aids tube elongation (not a hormone).
40. Pollen tube wall is made of
A. Cellulose
B. Pectin and callose
C. Lignin
D. Suberin
Answer: B
Explanation: Flexible wall supports growth.
41. Pollen–pistil interaction is species-specific because of
A. Size of pollen
B. Genetic compatibility
C. Shape of pistil
D. Environment
Answer: B
Explanation: Controlled genetically.
42. The egg apparatus consists of
A. Egg + 2 synergids
B. Egg + antipodals
C. Central cell + egg
D. Synergids only
Answer: A
Explanation: Egg apparatus = egg + 2 synergids.
43. Failure of pollen germination indicates
A. Fertilization
B. Compatibility
C. Incompatibility
D. Pollination
Answer: C
Explanation: Incompatible pollen fails to germinate.
44. Pollen tube guidance is controlled by
A. Mechanical force
B. Chemical attractants
C. Gravity
D. Light
Answer: B
Explanation: Chemotropic growth.
45. Which tissue transmits pollen tube?
A. Cortex
B. Vascular tissue
C. Transmitting tissue
D. Epidermis
Answer: C
Explanation: Specialized transmitting tissue.
46. Self-incompatibility was first discovered in
A. Wheat
B. Brassica
C. Maize
D. Rice
Answer: B
Explanation: Classic example from Brassica.
47. Pollen tube releases enzymes to
A. Digest embryo sac
B. Digest style tissue
C. Digest synergid wall
D. Digest ovule
Answer: C
Explanation: Helps entry into synergid.
48. Pollen grain germinates only when
A. It is viable
B. It lands on stigma
C. It is compatible
D. All of the above
Answer: D
Explanation: All conditions are required.
49. Rejection of pollen is an example of
A. Immune response
B. Mechanical response
C. Genetic control
D. Hormonal control
Answer: C
Explanation: Genetically regulated incompatibility.
50. The ultimate goal of pollen–pistil interaction is
A. Pollination
B. Pollen germination
C. Fertilization
D. Seed dispersal
Answer: C
Explanation: Entire process ensures successful fertilization.
