A characteristic feature of plant parasites is the

Analyze the question: It asks for a feature that is characteristic of parasitic plants, such as Cuscuta (dodder) and Striga (witchweed), and of parasitic fungi.

Explain the concept: A parasite lives on or in a host and takes food from it. To do this, many plant parasites have specialized structures that penetrate the host tissues and absorb nutrients and water. These structures are called haustoria.

Go through the options:

• A. Holdfast: This is an anchoring structure found in algae such as seaweeds. It attaches them to rocks and has nothing to do with parasitism.
• B. Rhizoids: These are root-like anchoring structures in mosses, liverworts, ferns' gametophytes, and fungi such as Rhizopus. They are not specific to parasites.
• C. Hanging roots: These are aerial or adventitious roots, such as the prop or hanging roots of epiphytes and banyan trees. They are not a feature of parasites.
• D. Haustoria: These are modified roots or hyphae that penetrate the host and absorb nutrients. Cuscuta and mistletoe (Loranthus) both use them. This is the characteristic feature of plant parasites.

Answer: The correct option is D, development of haustoria.

Exam tip: Link the words: Haustoria = Host. Whenever you see "parasite" in a plant question, think "haustoria" (suckers that tap the host).