Question

Movement of nutrients from soil to root in convective flow of water is _______

• A. Mass flow
• B. Diffusion
• C. Osmosis
• D. Root interception

Hint:

To distinguish nutrient transport mechanisms:
Convective water flow $\rightarrow$ Mass flow (Nitrogen, Calcium).
Concentration gradient $\rightarrow$ Diffusion (Phosphorus, Potassium).
Physical root growth $\rightarrow$ Root interception.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Nutrients in the soil must move from the bulk soil to the root surface to be absorbed.
This movement occurs through three primary mechanisms: mass flow, diffusion, and root interception.

Step 2: Detailed Explanation:
Let us analyze the three mechanisms of nutrient movement to the root surface:
1. Mass flow: This is the convective movement of dissolved nutrients along with the bulk flow of water toward the roots, driven primarily by plant transpiration.
As plants transpire, water is absorbed from the soil, pulling soluble nutrients (such as nitrates, sulfates, calcium, and magnesium) toward the root surface.
The rate of nutrient delivery via mass flow depends on the transpiration rate and the nutrient concentration in the soil solution. Thus, mass flow matches the description.
2. Diffusion: This is the movement of individual ions along a concentration gradient, from areas of high concentration in the bulk soil to lower concentration near the root surface.
This is the primary transport mechanism for highly immobile nutrients like phosphorus and potassium.
3. Root interception: Occurs as plant roots grow through the soil, making direct physical contact with nutrients adsorbed on soil particles.
4. Osmosis: Is the movement of water molecules across a semi-permeable membrane, rather than the transport of mineral nutrient ions to the root surface.

Step 3: Final Answer:
The movement of nutrients in convective flow of water is Mass flow, which corresponds to Option (A).