Part 4 — Pollination (types, agents, examples), outbreeding devices, pollen–pistil interaction (25 MCQs)

Q66. Pollination is best defined as:

a) Transfer of pollen from anther to stigma of same or another flower
b) Fusion of male and female gametes
c) Formation of pollen in anther
d) Seed dispersal

Answer: a) Transfer of pollen from anther to stigma of same or another flower

(a) Correct. Pollination = pollen transfer; fertilization = gamete fusion.

Q67. Self-pollination where pollen from an anther falls on stigma of same flower is called:

a) Autogamy
b) Geitonogamy
c) Xenogamy
d) Allogamy

Answer: a) Autogamy

(a) Correct. Autogamy = within same flower.
(b) Geitonogamy = between flowers of same plant (considered selfing genetically but pollination between different flowers).
(c,d) Xenogamy/allogamy = cross-pollination.

Q68. Transfer of pollen from one plant to the stigma of a flower on a different plant of same species is:

a) Autogamy
b) Geitonogamy
c) Xenogamy (cross-pollination)
d) Selfing

Answer: c) Xenogamy (cross-pollination)

(c) Correct. Xenogamy = cross-pollination between different plants, promotes genetic variation.

Q69. Wind-pollinated (anemophilous) flowers typically have:

a) Sticky, aromatic flowers with nectar
b) Small, inconspicuous flowers, abundant light pollen, large feathery stigmas
c) Bright colorful petals and strong scent
d) Deep corolla tube for insect proboscis

Answer: b) Small, inconspicuous flowers, abundant light pollen, large feathery stigmas

(b) Correct. Anemophilous flowers are not showy, produce copious lightweight pollen, and have feathery stigmas for capture.
(a,c,d) Typical of biotic (insect/bird) pollination.

Q70. Insect-pollinated flowers (entomophilous) commonly have:

a) Large exserted stigmas, no scent
b) Bright petals, nectar, scent, sticky pollen
c) Wind-dispersed pollen traits
d) Underwater pollination adaptations

Answer: b) Bright petals, nectar, scent, sticky pollen

(b) Correct. Entomophilous flowers attract insects via color and scent and provide rewards (nectar/pollen).
(a,c,d) Incorrect.

Q71. Which of the following plant pollination is adapted to bird pollinators (ornithophily)?

a) Red tubular flowers with no fragrance and abundant nectar (e.g., Butea)
b) Small green flowers without nectar
c) Wind-pollinated grasses
d) Nocturnal fragrant flowers

Answer: a) Red tubular flowers with no fragrance and abundant nectar (e.g., Butea)

(a) Correct. Birds attracted to bright red, tubular flowers with copious nectar; often scentless (birds have poor sense of smell).
Other options not bird-adapted.

Q72. Hydrophily is pollination by:

a) Wind
b) Water
c) Insects
d) Birds

Answer: b) Water

(b) Correct. Hydrophily = water-mediated pollination (common in some aquatic plants).
(a,c,d) Wrong agents.

Q73. Which of these is an outbreeding device that prevents self-pollination?

a) Protandry (anther matures first) or protogyny (stigma first)
b) Cleistogamy
c) Self-compatibility
d) Homogamy

Answer: a) Protandry (anther matures first) or protogyny (stigma first)

(a) Correct. Dichogamy (protandry/protogyny) prevents selfing by temporal separation.
(b) Cleistogamy promotes selfing.
(c) Self-compatibility allows selfing.
(d) Homogamy = same timing, may encourage selfing.

Q74. Self-incompatibility mechanism in plants achieves:

a) Promotes autogamy
b) Prevents self-fertilization genetically (rejects own pollen)
c) Attracts insects more strongly
d) Encourages apomixis

Answer: b) Prevents self-fertilization genetically (rejects own pollen)

(b) Correct. SI is genetic recognition preventing self-pollen germination/pollen tube growth.
Others incorrect.

Q75. Pollen–pistil incompatibility leading to pollen tube arrest in style is an example of:

a) Pre-zygotic barrier (post-pollination)
b) Post-zygotic barrier
c) Mechanical barrier only
d) Fertilization success

Answer: a) Pre-zygotic barrier (post-pollination)

(a) Correct. It prevents fertilization before zygote formation; classified as pre-zygotic (after pollination).
(b) Post-zygotic occurs after zygote formation.

Q76. Pollen-pistil interaction includes recognition of compatible pollen by:

a) Stomata only
b) Stigma and style tissues via biochemical signaling (adhesion, hydration, germination, tube growth)
c) Petals only
d) Anther only

Answer: b) Stigma and style tissues via biochemical signaling (adhesion, hydration, germination, tube growth)

(b) Correct. Pollen adhesion, hydration, germination on stigma, and guided tube growth in style rely on molecular signals.

Q77. Geitonogamy is pollination between:

a) Flowers of same plant (different flowers) — functionally selfing but mediated by pollinators
b) Flowers of different plants
c) Within same flower only
d) Fossil pollen transport

Answer: a) Flowers of same plant (different flowers)

(a) Correct. Geitonogamy genetically similar to autogamy (selfing) though pollen transfer is via pollinator.

Q78. Cleistogamous flowers are:

a) Always cross-pollinated
b) Do not open; self-pollinated leading to guaranteed seed set
c) Open widely to attract pollinators
d) Found only in aquatic plants

Answer: b) Do not open; self-pollinated leading to guaranteed seed set

(b) Correct. Cleistogamous flowers remain closed and self-pollinate (e.g., Viola).
(a,c,d) Wrong.

Q79. In wind pollination, pollen grains are typically:

a) Large and sticky
b) Small, light, and smooth
c) Flagellated
d) Encased in nectar

Answer: b) Small, light, and smooth

(b) Correct. Anemophilous pollen is lightweight and produced in abundance.
(a) Sticky/ornamented typical for insect pollination.

Q80. A pollen grain germinates on stigma, producing pollen tube which grows through:

a) Style and transmits sperms to embryo sac via micropyle or other entry point
b) Directly through integuments always via chalaza
c) Through anthers back to ovary
d) Through petals only

Answer: a) Style and transmits sperms to embryo sac via micropyle or other entry point

(a) Correct. Pollen tube usually enters ovule through micropyle (porogamy) but variations exist (chalazogamy).

Q81. Pollen grains of insect-pollinated species are often:

a) Smooth and tiny
b) Sticky, sculptured, heavier and nutrient-rich
c) Contain hooks for wind dispersal
d) Motile by flagella

Answer: b) Sticky, sculptured, heavier and nutrient-rich

(b) Correct. Adaptations attract insects and adhere to their bodies.

Q82. Porogamy describes pollen tube entering the ovule via:

a) Micropyle
b) Chalaza
c) Funiculus
d) None

Answer: a) Micropyle

(a) Correct. Porogamy = through micropyle; chalazogamy = through chalaza.

Q83. Outbreeding devices in plants include all EXCEPT:

a) Dichogamy
b) Heterostyly (different style lengths)
c) Self-incompatibility
d) Cleistogamy

Answer: d) Cleistogamy

(d) Correct. Cleistogamy promotes selfing, not outbreeding. Others favor outbreeding.

Q84. Heterostyly, like in Primula, ensures:

a) Selfing
b) Cross-pollination by ensuring reciprocal placement of stigma & anthers between morphs
c) Asexual reproduction
d) Male sterility only

Answer: b) Cross-pollination by ensuring reciprocal placement of stigma & anthers between morphs

(b) Correct. Heterostyly (pin/thrum) reduces self-pollination, promotes cross.

Q85. A pollen grain that germinates in the anther and produces tube which penetrates through anther wall leading to fertilization of ovules in same flower is an example of:

a) Autogamy
b) Hypogyny
c) Cleistogamy
d) Porogamy

Answer: a) Autogamy (or intramolecular selfing; more specifically, autogamy within flower)

(a) Correct. Pollen germinating within flower leads to selfing; cleistogamy are closed flowers — similar but not the same.

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Part 4 — Pollination (types, agents, examples), outbreeding devices, pollen–pistil interaction (25 MCQs)