Sexual reproduction in flowering plants practice · Mixed difficulty

Option B (FALSE) is correct because microspores develop into pollen grains, not ova (eggs).

Option A (Polyembryony) is correct because polyembryony is the occurrence of more than one embryo in a seed.

Option D (Both (1) and (2)) is correct because nucellar and integumentary embryos are derived from maternal tissue and are genetically identical to the female plant.

Option D (Central cell) is correct because the central cell is the largest cell in the embryo sac and contains two polar nuclei.

Option A (Sporopollenin) is correct because sporopollenin is a highly resistant polymer that protects pollen grains from degradation, allowing them to be preserved as fossils.

Option D (All of the above) is correct because a micropyle is a small pore for water entry, a gap where integuments are absent, and necessary for seed existence.

Option D (Has seven celled eight nucleated structure and is monosporic) is correct because the Polygonum type embryo sac is the most common type and has this structure and origin.

Option C (Scutellum) is correct because pollen grain, synergid, and polar nucleus are all haploid (n) structures, while the scutellum is a diploid (2n) structure.

Option C (Both (a) and (b)) is correct because the pollen tube wall is composed of both cellulose and pectin.

Option B (380) is correct because the meiocyte (diploid cell undergoing meiosis) of a butterfly has 380 chromosomes.

Option B (Mango) is correct because mango trees exhibit a distinct recovery phase after fruiting, where they build up resources for the next season.

Option B (Versatile stamens) is the feature NOT of entomophilous flowers because versatile stamens are more commonly associated with anemophilous (wind-pollinated) flowers.

Option B (24) is correct because the endosperm is triploid (3n), and if the leaf (2n) has 16 chromosomes, then the endosperm has (3/2) * 16 = 24 chromosomes.

Option C (Both (a) and (b)) is correct because the pericarp is the mature ovary wall, which forms the fruit wall.

Option D is correct because the transfer of pollen grains to the stigma of the same flower is self-pollination (autogamy), not cross-pollination.

Option C (If Assertion is true but Reason is false) is correct because the assertion about nucellar endosperm formation is correct, but the reason is false as coconut initially has free-nuclear endosperm which later becomes cellular.

Option D (None of the above) is correct because apomixis arises due to specific genetic and developmental factors, not simply rapid or slow reproduction.

Option C (16) is correct because each pollen mother cell produces 4 pollen grains. Therefore, to produce 64 pollen grains, 16 pollen mother cells are required (64 / 4 = 16).

Option C (Vallisneria) is correct because Vallisneria is a classic example of a plant that undergoes hydrophily, or pollination by water.

Option C (ABB, AB) is correct because endosperm is formed by the fusion of two polar nuclei (BB) and one sperm (A), and the embryo is formed by the fusion of one sperm (A) and one egg (B).

Option D is correct because wind-pollinated flowers typically have dry pollen grains, not surrounded by a mucilaginous covering which is more common in insect or water-pollinated flowers.

Option D (Pollen wall has cavities containing proteins) is correct because while pollen walls do contain sporopollenin and are resistant to degradation, the statement that pollen walls have cavities containing proteins is generally true and not wrong.

Option C (Both (a) and (b)) is correct because the intine, the inner layer of the pollen grain wall, is composed of cellulose and pectin.

Option D (None of these) is correct because self-sterility, dichogamy, and heterogamy are all mechanisms that promote allogamy, but none are absolutely essential for it to occur.

Option B (Perform pollination) is correct because bees are crucial pollinators for many agricultural crops.

Option D (Mango) is correct because Neelakuranji, wheat, and radish are monocarpic plants (flowering once in their lifetime), while mango is a polycarpic plant (flowering many times).

Option D (All of these) is correct because polyembryony, the condition of having multiple embryos in a single ovule, is common in Citrus, Orange, and Mango.

Option C (Geitonogamy) is correct because geitonogamy is the transfer of pollen from the anther of one flower to the stigma of another flower on the same plant.

Option B (Capsella) is correct because Capsella exhibits onagrad type embryo development, characterized by specific cell division patterns during embryogenesis.