Q30. Which statement about cleistogamous flowers is correct?
[NEET 2022, Phase 1]
(A) They are invariably cross-pollinated
(B) They remain closed and are invariably autogamous
(C) They never form viable seeds
(D) They depend on insect pollinators for seed set
Answer: (B) They remain closed and are invariably autogamous
Explanation: Cleistogamous flowers remain closed, bringing the anther and stigma into close contact within the same flower. Consequently self-pollination is assured without an external pollinating agent. This promotes reliable seed set but generally restricts outcrossing and associated genetic variation.
Q29. After a compatible pollen grain reaches the stigma, what sequence leads most directly to fertilisation?
[CGPSC Mains 2022, General Science — MCQ adapted from descriptive PYQ]
(A) Seed dispersal, embryo formation, pollen growth
(B) Pollen germination, pollen-tube growth, male-gamete delivery
(C) Fruit ripening, meiosis, anther dehiscence
(D) Petal abscission, germination of seed, pollination
Answer: (B) Pollen germination, pollen-tube growth, male-gamete delivery
Explanation: Compatible pollen hydrates and germinates on the stigma, producing a pollen tube that traverses the style. It approaches an ovule and discharges two male gametes into the embryo sac. One fuses with the egg and the other participates in triple fusion.
Q28. The commercial spice clove consists of which plant structure?
[UPPSC Combined State Exam, General Studies, 24 October 2021]
(A) Terminal vegetative bud
(B) Accessory bud
(C) Dried flower bud
(D) Underground root bud
Answer: (C) Dried flower bud
Explanation: Cloves are the dried, unopened aromatic flower buds of Syzygium aromaticum. A flower bud contains structures that would develop into the reproductive flower. This makes clove an example of a commercially used floral part rather than a root or vegetative bud.
Q27. A typical mature angiosperm embryo sac is usually described as which of the following?
[NEET 2021]
(A) Four-nucleate and four-celled
(B) Eight-nucleate and seven-celled
(C) Eight-nucleate and eight-celled
(D) Six-nucleate and seven-celled
Answer: (B) Eight-nucleate and seven-celled
Explanation: The common Polygonum-type embryo sac contains an egg, two synergids, three antipodal cells and one central cell. The central cell houses two polar nuclei, resulting in seven cells but eight nuclei before the fusion of polar nuclei.
Q26. Which sequence correctly shows events from pollination to seedling formation?
[UPSC CDS I 2020, General Knowledge]
(A) Seedling → embryo → pollination → fertilisation
(B) Embryo → seedling → pollination → fertilisation
(C) Pollination → fertilisation → zygote division → embryo → seedling
(D) Seedling → zygote division → pollination → fertilisation
Answer: (C) Pollination → fertilisation → zygote division → embryo → seedling
Explanation: Pollination first places pollen on the stigma. Following pollen-tube growth, fertilisation produces a zygote, which divides and develops into an embryo inside a seed. Under favourable conditions the mature seed germinates to produce a young seedling.
Q25. Which order correctly lists these floral structures roughly from innermost to outermost: ovule (1), ovary (2), stigma (3), petal (4)?
[SSC CHSL, 20 October 2020, Shift 2]
(A) 1, 2, 3, 4
(B) 4, 3, 2, 1
(C) 3, 2, 4, 1
(D) 1, 3, 2, 4
Answer: (A) 1, 2, 3, 4
Explanation: Ovules are enclosed inside the ovary, which is part of the pistil. The stigma is positioned at the upper end of the pistil, while petals occur in a surrounding floral whorl. Therefore the requested inside-to-outside conceptual order is ovule, ovary, stigma, petal.
Q24. Transfer of pollen from a flower to another flower on the same plant is called what?
[MPPSC State Service, General Studies 2019]
(A) Autogamy
(B) Geitonogamy
(C) Xenogamy
(D) Apomixis
Answer: (B) Geitonogamy
Explanation: Geitonogamy takes place between different flowers belonging to a single plant. It may require a pollinating agent, resembling cross-pollination functionally. However, its pollen originates from the same individual, making it genetically comparable to self-pollination.
Q23. Double fertilisation is a characteristic reproductive feature of which group?
[RRB JE CBT I, 28 June 2019, Shift 3]
(A) Bryophytes
(B) Gymnosperms
(C) Ferns
(D) Angiosperms
Answer: (D) Angiosperms
Explanation: In flowering plants one male gamete unites with the egg to form a diploid zygote, while the other fuses with the two polar nuclei to make the triploid primary endosperm nucleus. Together these events constitute double fertilisation.
Q22. What is the name of the persistent nucellus that remains in some mature seeds?
[NEET 2019]
(A) Perisperm
(B) Pericarp
(C) Endosperm
(D) Coleoptile
Answer: (A) Perisperm
Explanation: Perisperm is residual nucellar tissue retained in a mature seed, such as black pepper or beet. Unlike endosperm, which forms after triple fusion, perisperm comes from the maternal sporophytic tissue already present in the ovule before fertilisation.
Q21. What is the swollen basal portion of a flower’s carpel called?
[SSC CHSL, 26 March 2018, Shift 2]
(A) Ovary
(B) Style
(C) Stigma
(D) Anther
Answer: (A) Ovary
Explanation: The carpel generally consists of stigma, style and ovary. The ovary is its swollen basal region and encloses ovules attached to the placenta. It commonly enlarges into the fruit after fertilisation, whereas its ovules become seeds.
