Question

The plant body having holdfast, stipe and frond is a characteristic of

• A. Laminaria
• B. Volvox
• C. Gelidium
• D. Porphyra

Answer 1

The Correct Option is A

The question asks to identify the organism whose plant body is typically differentiated into three distinct parts: a holdfast, a stipe, and a frond.

• Holdfast: A root-like structure that anchors the alga to a substrate (like rocks).
• Stipe: A stalk-like structure, analogous to a stem, that supports the fronds.
• Frond: A leaf-like, flattened blade, which is the primary photosynthetic part of the alga.

This type of body organization is characteristic of larger, more complex algae, particularly certain members of the Phaeophyceae (Brown Algae).

Let's analyze the options: 

• Laminaria: This is a genus of large brown algae, commonly known as kelp. Kelps are well-known for having a well-differentiated thallus consisting of a strong holdfast, a distinct stipe (which can be quite long in some species), and large, blade-like fronds. This matches the description perfectly.
• Volvox: This is a genus of colonial green algae (Chlorophyceae). It forms spherical colonies of individual cells embedded in a gelatinous matrix. It lacks differentiation into holdfast, stipe, and frond.
• Gelidium: This is a genus of red algae (Rhodophyceae). While it has a macroscopic thallus, its structure is typically branched and filamentous or somewhat flattened, and it does not exhibit the clear division into holdfast, stipe, and frond characteristic of kelps.
• Porphyra: This is a genus of red algae (Rhodophyceae), commonly known as nori. Its thallus is typically a thin, sheet-like blade (frond) attached by a small holdfast, but it lacks a distinct stipe.

Therefore, the plant body having a holdfast, stipe, and frond is a characteristic feature of Laminaria.

Answer 2

The plant body having holdfast, stipe, and frond is characteristic of Laminaria.

Laminaria is a type of brown algae (a member of the class Phaeophyceae). It has a well-developed structure consisting of:
Holdfast: Anchors the plant to rocks or the sea floor.
Stipe: The stem-like structure that supports the fronds.
Fronds: The leaf-like structures that are responsible for photosynthesis.

Other options:

• Volvox is a colonial green alga and does not have the same structure of holdfast, stipe, and frond.
• Gelidium is a red alga that typically has a different morphology.
• Porphyra is a type of red algae, and its structure also differs from that of Laminaria.

Thus, the correct answer is (A) : Laminaria.