Sexual reproduction in flowering plants practice · Mixed difficulty

Option D (All of these) is correct because wind-pollinated pollens are typically non-sticky, light, and produced in large numbers to increase the chances of successful pollination.

Option C (15, 5, 10) is correct because endosperm is triploid (3n), egg cell is haploid (n), and polar nuclei are haploid (n).

Option D (Xenogamy) is correct because xenogamy involves the transfer of pollen grains from one plant to the stigma of another plant, leading to genetically different pollen grains.

Option C (40) is correct because each microspore mother cell produces 4 pollen grains after meiotic division. Therefore, ten microspore mother cells will produce 40 pollen grains.

Option D (Cleistogamy) is correct because Commelina often exhibits cleistogamy, where flowers do not open and self-pollination occurs within the closed flower.

Option C (Endosperm) is correct because endosperm is the product of triple fusion, which occurs during double fertilization.

Option D is correct because germ pores are present on the exine (outer wall) of the pollen grain, not the intine (inner wall).

Option B (Plasmamembrane) is correct because the cytoplasm of any cell, including a pollen grain, is surrounded by the plasma membrane.

Option D (Mitosis) is correct because apomixis is a form of asexual reproduction, and therefore relies on mitosis for cell division to produce genetically identical offspring.

Option A (Male gamete fuses with female gamete) is correct because syngamy is the fusion of the male and female gametes to form a zygote.

Option A (Nucellus or integuments) is correct because adventive embryony involves embryos developing directly from somatic cells of the nucellus or integuments.

Option B (Both A and R are true and R is not the correct explanation of A) is correct because both the assertion (female gametophyte is eight nucleated) and the reason (double fertilization occurs) are true, but double fertilization doesn't explain why the female gametophyte is eight nucleated.

Option A (Cucumber) is correct because cucumber flowers are unisexual, meaning they have either male or female reproductive parts, but not both.

Option A (Haploid plant) is correct because a plant raised from a single germinating pollen grain is haploid, as pollen grains are haploid.

Option B (If both Assertion and Reason are true but Reason is not the correct explanation of Assertion) is correct because both statements are true, but parthenocarpy isn't the reason why ovaries form fruits after fertilization.

The correct answer is C (Both (a) and (b)) because both Castor and Coconut are known to have endospermic seeds, where the endosperm persists in the mature seed.

Option D (Maternal saprophytic tissue in ovule) is correct because apomictic embryos in Citrus often arise from nucellar tissue, which is maternal sporophytic tissue.

Option A (Chemotropism) is correct because the pollen tube's growth towards the ovule is guided by chemical signals.

Option B (Ovule) is correct because the megasporangium with its protective integuments is the ovule.

The correct answer is A (TRUE) because increasing the number of pollen grains enhances the chances of successful pollination in wind and water-pollinated plants due to the randomness of these processes.

Option A (Middle layer) is correct because the middle layer of the anther wall, consisting of 2-3 layers of cells, is ephemeral and degenerates during microspore maturation.

Option C (Unfertilized ovule) is correct because the ovule contains the female gametophyte (embryo sac), which is one generation, and is itself part of the sporophyte (parent plant), which is the other generation.

Option B (Banana) is correct because banana plants are monocarpic, meaning they flower once and then die.

Option C (Double fertilisation) is correct because endosperm formation is a direct result of the fusion of a sperm nucleus with the polar nuclei during double fertilization.

Option B (12) is correct because gametes are haploid, containing half the number of chromosomes as the diploid root cells.

Option D (I and II) is correct because polyembryony is commonly reported in Citrus and Mango.

Option B (Commelina – I) is correct because certain species of Commelina produce both chasmogamous (open) and cleistogamous (closed) flowers.

Option C (Only B&C) is correct because both apomixis and cleistogamy assure seed set without the requirement of pollinators.

Option A (Mitosis) is correct because mitosis is responsible for cell division that produces sperms from microspores, wound healing, and restoration of karyocytoplasmic ratio.

Option D (Fragrance) is correct because nectar, safe place for egg laying, and pollen grains are direct rewards for the insect in entomophily, while fragrance is just an attractant.