Imagine a live twig from a tree and examine the cut surface of the twig with a magnifying glass. You locate a vascular tissue and observe a growing droplet of fluid exuding from the cut surface This fluid is probably

Options

A. Phloem sap
B. Xylem sap
C. guttation fluid
D. Only water

Answer

To solve the question regarding the fluid exuding from the cut surface of a live twig, we can follow these steps:

### Step-by-Step Solution:

1. **Examine the Cut Surface**: Start by observing the cut surface of the twig with a magnifying glass. This will allow you to see the vascular tissues clearly.

2. **Identify Vascular Tissue**: Locate the vascular tissues in the twig. Vascular tissues include xylem and phloem, which are responsible for the transport of water, nutrients, and food.

3. **Observe the Fluid Droplet**: Notice the droplet of fluid that is forming at the cut surface. This is an important observation as it indicates that some fluid is exuding from the vascular tissue.

4. **Consider the Source of the Fluid**: Since the twig has been separated from the plant, we need to consider the physiological processes at play. The root system, which typically contributes to water uptake and root pressure, is absent.

5. **Eliminate Guttation**: Guttation is the process where water is exuded from the leaves due to root pressure. Since the twig is cut and lacks roots, guttation cannot occur in this scenario.

6. **Distinguish Between Phloem and Xylem**:
- **Xylem** is responsible for transporting water and minerals from the roots to the leaves. However, in this case, since the twig is cut, the xylem cannot transport water effectively.
- **Phloem** is responsible for transporting sugars and other organic nutrients from the leaves down to other parts of the plant. Since the twig is still connected to the leaves, it is likely that phloem sap is being exuded.

7. **Conclude the Type of Fluid**: Given the absence of root pressure and the fact that the twig is still connected to the leaves, the fluid exuding from the cut surface is most likely phloem sap, which contains sugars (like sucrose), some hormones, and water.

### Final Answer:
The fluid exuding from the cut surface of the twig is probably **phloem sap**.

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