Question

From the anatomical point of view meristeles in a dictyostele are

• A. Collateral bundles
• B. Amphicribral bundles
• C. Bicolateral bundles
• D. Amphivasal bundles

Hint:

In dictyostele, vascular bundles are arranged in a way that allows for efficient nutrient and water transport with both xylem and phloem present in a particular arrangement.

Answer 1

The Correct Option is D

Step 1: Understanding the terms.
In dictyostele, the vascular bundles are arranged in such a way that they have both xylem and phloem tissues arranged in a circular manner. In dictyostele, the vascular bundles are amphivasal. This means that the xylem is located in the center and phloem is located at the periphery. Step 2: Conclusion.
The correct answer is (4) Amphivasal bundles.

Answer 2

A dictyostele is a type of siphonostele (common in fern rhizomes) that is broken up into a ring of separate vascular strands called meristeles. The question asks about the internal tissue arrangement within each of these meristeles. Let's go through each option.

1. Collateral bundles: In a collateral arrangement, xylem and phloem sit side by side on the same radius, with xylem usually to the inside and phloem to the outside - this is the typical arrangement in most dicot stems, not the concentric arrangement seen in fern meristeles.
2. Amphicribral bundles: Here phloem completely surrounds a central xylem core. While this concentric pattern is seen in some fern vascular strands, it is not the specific arrangement associated with dictyostelic meristeles in this context.
3. Bicolateral bundles: This type has phloem on both the outer and inner faces of the xylem, a pattern typical of families like Cucurbitaceae and Solanaceae, unrelated to fern stelar anatomy.
4. Amphivasal bundles: Here xylem completely surrounds a central phloem strand - the reverse of the amphicribral pattern. This concentric, xylem-surrounding arrangement is the one associated with the meristeles of a dictyostele.

Among the tissue arrangements listed, the concentric xylem-surrounding-phloem pattern is the one that matches dictyostelic meristeles.

Therefore, the correct answer is Amphivasal bundles.