Question

The greatest difference in health between two groups of plants of the same species, one group with mycorrhizae and one group without mycorrhizae, would be in an environment

(A) where nitrogen-fixing bacteria are abundant.

(B) that has soil with poor drainage.

(C) that has hot summers and cold winters.

(D) in which the soil is relatively deficient in mineral nutrients.

Short answer

1. The option “where nitrogen-fixing bacteria are abundant” is false.

2. The option “that has soil with poor drainage” isfalse.

3. The option “that has hot summers and cold winters” is false.

4. The option “in which the soil is relatively deficient in mineral nutrients” is true.

Step-by-step solution

Symbiosis in plants

Plants are autotrophic and obtain glucose directly from photosynthesis. However, many plants show symbiosis with microorganisms to get the nutrients. For example, mycorrhiza is the mutualism of plants and fungi. Rhizobacteria are present in the roots of legumes.

Explanation of option (A)

Mycorrhiza is the association present between fungi and plants. The hyphae of the fungi assist in absorbing nutrients and water by increasing the surface area.

Therefore, a group of plants with mycorrhiza and without mycorrhiza is not dependent on nitrogen-fixing bacteria.

Thus, the given option is false.

Explanation of option (B)

Plants that present in soil with poor drainage do not show symbiosis with fungi. Plants might die from the poor drainage in soil due to the rotting of the roots.

Therefore, no microorganism exhibits symbiosis with plants that are present in poor drainage due to unhealthy roots.

Thus, the given option is false.

Explanation of option (C)

The weather or climate does not entirely affect the symbiosis between plants and fungi. The reserved food of the plants is available for fungi, and they continue to help the roots in absorption.

Therefore, hot summers and cold winters cannot show the difference between plants with and without mycorrhiza.

Thus, the given option is false.

Explanation of option (D)

The plant with mycorrhiza association would be present in the environment with poor nutrients because hyphae of the fungus in the plants increase the efficiency of roots in absorbing nutrients from the soil.

Therefore, plants without mycorrhiza would be found in nutrient-rich environments.

Thus, the given option is true.