Question

Dryopteris differs from Funaria in having
(a) An independent gametophyte
(b) An independent sporophyte
(c) Swimming antherozoids
(d) Archegonia

Answer 1

Hint: Haploid plant body produces haploid gametes that fuse to form a diploid plant body. It produces haploid spores to give rise to a haploid plant body. Dryopteris and Funaria differ in the dependency of these plant bodies on each other.

Complete answer:
Dryopteris is a type of fern which is a member of Pteridophyta. The main plant body is a diploid sporophyte represented by a dominant, independent, photosynthetic vascular plant body. It alternates with multicellular and independent but short-lived haploid gametophyte.
Funaria is a moss which is a type of Bryophyte. The main plant body is a dominant, independent, photosynthetic, and haploid gametophyte. It alternates with a short-lived multicellular sporophyte which is totally or partially dependent on the gametophyte.

Additional Information: -The main plant body of Funaria is radially symmetrical with a branched axis, on which the leaves are radially arranged.
-The main axis bears antheridia representing male reproductive structures while the lateral branch bears female reproductive organs or archegonia.
-The antheridium bursts to release antherozoids. They swim in the water and are attracted to the chemotactic factors released by the archegonia.
-The zygote formed by the fusion of antherozoid and egg develops a thick wall around it. The diploid structure so formed is known as oospore that divides and develops into a sporophyte while still being on the gametophytic plant body.
-Dryopteris is a pteridophyte belonging to the class of Pteropsida with the diploid as the parent plant body.
-Their main characteristic feature though is the presence of sporophylls. These are the leaves bearing sporangia.
-The haploid spores are released from the sporangium and dispersed by wind currents to a new substratum.
-After falling on suitable soil, the germination of spores produces a green, thalloid, and free-living gametophyte known as prothallus. It represents the gametophyte stage in its life cycle.
So, the correct answer is ‘An independent sporophyte.’

Note: -In any sexually reproducing plant, there is an alternation of generation between the gametophytic and sporophytic stage.
-Based on which, three life cycles are observed in the plant kingdom- The haplontic life cycle exhibited by algae, the diplontic life cycle by gymnosperms, and angiosperms, haplo-diplontic life cycle in bryophytes and pteridophytes.