Question

Elater mechanism for seed dispersal is exhibited by
A. Riccia
B. Marchantia
C. Dryopteris
D. Funaria

Answer 1

Hint: Elaters are long spindle shaped structures with the spiral thickening within them. They are hygroscopic in nature. They are complete cells. They are mostly found in liverworts.

Complete Answer:
- Elaters are the cells that develop into sporophyte alongside the spores. Elaters change shape in response to the moisture present in the environment. Thus they are hygroscopic in nature. These elaters function in spore dispersal for the plants that do not seed (non-angiosperm plants).
- For example the elaters are found in liverworts like Marchantia. Here the elaters are unattached. In some species, the elaters remain attached to the inside of the spore capsule.
(I) Riccia- It is a hermaphrodite. Male and female parts are present on the same plant. There is no requirement for elaters.
(II) Dryopteris- It is a fern. So the elaters are absent.
(III) Funaria- It is a hermaphrodite. Male and female parts are present on the same plant. They have paraphysis which is a large number of fine hairs present with antheridia. They help in seed dispersal.

The correct answer is B. Elaters are present in Marchantia.

Additional Information: Marchantia is a gametophyte. It bears both male sex organ called the antheridia and female eggs called the archegonia. The antherozoids are male gametes that swim in water to fertilise with the egg of another marchantia plant. They do not have vascular bundles.

Note: Seed dispersal is the movement of seeds or spread of seeds away from the plant. The angiospermic plants, seeds are propagated by various vectors like birds, animals, and insects. In the aquatic plants, the seeds are dispersed by flowing water.