Suppose a plant has tuberous roots and rhizomes both as underground structures. How can you distinguish a root from rhizome ?

Options

A. Root has no scale leaves and nodes and internodes.
B. Root is thicker and rhizome is thinner.
C. Root remains non-green and rhizome becomes green on exposure to sunlight.
D. Root bear root hairs and rhizome does not bear any hairs

Answer

To distinguish between a root and a rhizome in a plant that has both tuberous roots and rhizomes, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Structure**:
- First, observe the underground structure you are examining. Determine if it is a root or a rhizome.

2. **Check for Scale Leaves**:
- Roots do not have scale leaves, while rhizomes do. Scale leaves are small, modified leaves that can be found on rhizomes.

3. **Examine Nodes and Internodes**:
- Roots lack nodes and internodes, whereas rhizomes have distinct nodes (points where leaves or branches can grow) and internodes (the segments between nodes).

4. **Thickness Comparison**:
- Generally, roots are thicker compared to rhizomes, which tend to be thinner and more elongated.

5. **Color and Exposure**:
- Roots remain non-green regardless of exposure to sunlight, while rhizomes can become green when exposed to light due to chlorophyll.

6. **Presence of Root Hairs**:
- Roots bear root hairs that help in the absorption of water and nutrients, while rhizomes do not have root hairs.

7. **Functionality**:
- While both structures can serve as storage organs, roots are modified lateral roots for storage, and rhizomes are modified stems that grow horizontally and also serve as storage.

### Summary:
- **Roots**: No scale leaves, no nodes/internodes, thicker, non-green, bear root hairs.
- **Rhizomes**: Have scale leaves, possess nodes/internodes, thinner, can be green, do not bear root hairs.