Plant Kingdom – Gymnosperms: NEET MCQs with Answers

Explanation: In gymnosperms the microspores develop into pollen grains (male gametophytes) within the microsporangia. All gymnosperms are heterosporous, so none is homosporous, and megasporophylls bearing ovules cluster to form female cones, not male cones. Since only the statement on pollen development is true, 'All of these' cannot be right.

Explanation: Pinus is monoecious, bearing male and female cones on the same plant, so 'Pinus - Dioecious' is wrong. Cycas is dioecious, Salvinia is heterosporous and Equisetum is homosporous.

Explanation: Sequoia (giant redwood) is one of the tallest tree species. Gymnosperms are heterosporous only, Salvinia is a pteridophyte (water fern), and gymnosperm leaves (needle-like, thick cuticle, sunken stomata) are well adapted to extreme climates.

Explanation: Gymnosperm phloem consists of sieve cells and albuminous cells; the more advanced sieve tubes and companion cells found in angiosperms are absent. Similarly, their xylem has tracheids but no vessels.

Explanation: The roots of Pinus form an obligate mycorrhizal association with fungi. The fungal partner greatly increases the absorption of water and minerals, especially phosphorus, without which the seedling cannot establish itself.

Explanation: In gymnosperms the ovules are naked — they are not enclosed by an ovary wall. Both Selaginella and Salvinia are heterosporous, Cedrus has a branched stem while Cycas is unbranched, and horsetails (Equisetum) are pteridophytes.

Explanation: The pollen grains of Pinus bear two lateral bladder-like wings formed by the separation of the exine from the intine. These wings make the pollen buoyant and aid its dispersal by wind.

Explanation: Pinus is MONOECIOUS — the male and female cones are borne on the same tree. Cycas is dioecious, Salvinia is heterosporous and Equisetum is homosporous, so those three matches are correct.

Explanation: Sequoia, the giant redwood, is one of the tallest trees in the world. Gymnosperms are exclusively heterosporous, Salvinia is a pteridophyte, and gymnosperm leaves are very well adapted to extremes of temperature, humidity and wind.

Explanation: In Pinus, as in all gymnosperms, the male gametophyte (pollen grain) and the female gametophyte remain enclosed within the sporangia retained on the sporophyte. Marchantia and Funaria are bryophytes and Pteris is a fern, all of which have free-living gametophytes.

Explanation: Peritrichous flagellation means flagella distributed all over the body surface of a bacterial cell, as in Escherichia coli — A-L. Ginkgo is called a living fossil because it is the single living genus of a large fossil order — B-J. The rhizophore, a leafless, colourless, positively geotropic structure arising at the point of bifurcation of the stem, occurs in Selaginella — C-M. Wolffia is the smallest flowering plant — D-N. Macrocystis, a brown alga about 40–60 m long, is the largest perennial alga — E-K.

Explanation: In conifers (gymnosperms) the endosperm is a haploid tissue formed BEFORE fertilisation, since it is simply the female gametophyte. In angiosperms such as grasses the triploid endosperm is formed after fertilisation as a result of triple fusion. Tracheids, pollen tubes and seeds from ovules are common to both groups.

Explanation: As one proceeds from thallophyta towards angiosperms there is a gradual reduction in the size of the gametophyte and of its sex organs, accompanied by a progressive elaboration of the sporophyte. The gametophytic phase falls from about 90% in thallophytes and 75% in bryophytes to roughly 50% in pteridophytes, 25% in gymnosperms and 10% in angiosperms.

Explanation: In all gymnosperms except the order Gnetales, the xylem consists of xylem parenchyma and tracheids with bordered pits but lacks vessels. Gnetum possesses vessel elements and also lacks archegonia in the female gametophyte — two distinctly angiospermic features that make Gnetales the most advanced gymnosperms and a connecting link between the two groups.

Explanation: In angiosperms the functional megaspore — usually the chalazal one of the four produced by meiosis — enlarges and divides mitotically to give rise to the embryo sac, which is the mature female gametophyte. The other three megaspores degenerate.