Question

Rhizoids of hepaticopsida and anthocerotopsida are
a. Multicellular and branched
b. Unicellular and unbranched
c. Unicellular and branched
d. Multicellular and unbranched

Answer 1

Rhizoids are a structure in plants and fungi that functions like a root for support or absorption. In fungi, they are small branching hyphae growing downwards from stolons anchoring fungus. In land plants, rhizoids are trichomes that anchor plants to the ground.

Complete answer:
To answer this question we need to have knowledge about rhizoids and bryophytes.
Bryophytes are group consisting of three divisions of non-vascular land plants-
- Liverworts,
- Hornworts,
- Mosses

Bryophytes produce enclosed reproductive structures, and thus reproduce through spores.
Some features of bryophytes:
- Life cycle is dominated by gametophyte stage
- Sporophytes are unbranched
- Lack true vascular tissue

Rhizoids are filamentous outgrowth extending from lower epidermal cells in bryophytes and algae and functions like roots providing support and absorption. The rhizoids attach gametophyte to the substratum and facilitate absorption of water and minerals.

Hepaticopsida (Liverworts):
General Characters:
- Hepaticopsida is derived from a latin word Hepatica which means liver. Hence commonly known as liverworts.
- Plant body is gametophytic and the gametophyte may either be thalloid or foliose.
- Rhizoids are unicellular and branched.
- Members may be monoecious or dioecious.
- Sporophyte is either simple or may be differentiated into foot, seta and capsule.
- Elaters are unicellular, hygroscopic with spiral thickenings.
- Capsule wall is several layers thick and lacks a stomata.

Anthocerotopsida (Hornworts):
General Characters:
- Plant body is flat, dorsiventral, thalloid, gametophytic.
- Smooth walled rhizoids are present.
- Sporophyte is differentiated into a foot, meristematic zone and capsule therefore it continues to grow indefinitely.
- Capsule wall is thick and the epidermis has a stomata.

Therefore, the answer is b, unicellular and unbranched.

Additional information:
The term "Bryophyta" was first suggested by Braun (1964). G.M. Smith placed this between Algae and Pteridophytes.

Note: Economic importance of bryophytes:
Environmental: Soil conditioning, bioindicators, pesticides

Certain bryophytes are useful to the environment. They have shown to help improve water retention. They are used in pollution studies to indicate soil pollution, air pollution, and UV-B radiation. Some bryophytes produce natural pesticides and few other produce chemicals, which protect them from being eaten by slugs.
Commercial: Fuel, packaging, wound dressing
Peat is a fuel produced from dried bryophytes, (Sphagnum).
The antibiotic properties of Bryophytes and their ability to retain water make them useful packaging material for vegetables etc.
Also, because of antibiotic properties, Sphagnum was used as a surgical dressing in World War I.