Supply end in solute transport is

Options

A. Root
B. Stem
C. Green leaves and storage organs
D. Xylem and phloem.

Answer

To solve the question regarding the supply end in solute transport, we need to analyze the options provided and understand the role of different plant structures in the transport of solutes, particularly sugars.

### Step-by-Step Solution:

1. **Understanding Solute Transport**:
- In plants, solute transport refers to the movement of substances like sugars and nutrients from one part of the plant to another.

2. **Identifying the Supply End**:
- The "supply end" is defined as the site where solutes, particularly sugars, are present in higher concentrations. This is typically where they are either synthesized or stored.

3. **Evaluating the Options**:
- **Roots**: The roots primarily function in the absorption of water and minerals from the soil. They are not the supply end.
- **Stem**: The stem acts as a support structure and also helps in transporting substances but is not primarily the site of sugar synthesis.
- **Green Leaves and Storage Organs**: The green leaves are the primary sites of photosynthesis where sugars are synthesized. Storage organs, such as certain parts of the stem and roots, store these sugars. Therefore, this option is a strong candidate for the supply end.
- **Xylem and Phloem**: These are the vascular tissues responsible for the transport of water (xylem) and nutrients/sugars (phloem). They are not the supply end but rather the conduits for transport.

4. **Conclusion**:
- Based on the analysis, the correct answer is **green leaves and storage organs** as they are the sites where sugars are synthesized and stored, making them the supply end in solute transport.

### Final Answer:
The supply end in solute transport is **green leaves and storage organs**.