Question

What are rhizoids and what is their function?

Answer 1

Hint: Rhizoid is a short, thin filament which is found in fungi and in certain plants and sponges that anchors the growing which means the vegetative body of the organism to a substratum and is capable of absorbing the essential nutrients. In fungi, the rhizoid is found in the thallus and it resembles a root.

Complete answer:
Rhizoids are basically simple, hair-like projections that grow out of the epidermal cells of bryophytes. Bryophytes are an informal division that comprises three groups of nonvascular plants, namely mosses, liverworts, and hornworts. Prominent characteristics of bryophytes are the absence of true roots, stems and leaves.

In land plants, rhizoids are trichomes that help in anchoring the plant to the ground. In the liverworts, they are either absent or unicellular, but multicelled in mosses. In vascular plants, they are called root hairs and can be unicellular or multicellular.

Function of rhizoids are as follows:
- Rhizoids perform the function of roots, essentially in anchoring the plants into the surface.
- It may serve either as a feeding organ as in Rhizopus or to anchor the thallus to its substratum like in Chytridium.
- In plants, such as liverworts and mosses which belongs to the division Bryophyta, rhizoids attach the gametophyte to the substratum and facilitate the absorption of minerals and water

Note: In fungi, rhizoids are small branching hyphae that grows downwards from the stolons that anchor the fungus to the substrate, where they release the digestive enzymes and helps in absorbing the digested organic material. This is why fungí are called heterotrophic by absorption. We must note that rhizoids may be unicellular or multicellular