Food in form of i s transported by the vascular tissue phloem from a source to a sink.

Options

A. starch
B. sucrose
C. glucose
D. amino acids

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the form in which food is transported by the vascular tissue phloem from a source to a sink.

2. **Identifying the Source and Sink**:
- The source is typically a photosynthetic organ, such as leaves, where food (sugars) is produced through photosynthesis.
- The sink is a non-photosynthetic organ, such as roots or fruits, where the food is utilized or stored.

3. **Form of Food Transported**:
- The food produced in the leaves is primarily in the form of glucose, which is a simple sugar.
- However, before transport, glucose is converted into sucrose, which is a disaccharide. This conversion is important because sucrose is a non-reducing sugar, making it less reactive and more stable for transport.

4. **Mechanism of Transport**:
- The transport of food in the phloem occurs through a process known as translocation. The accepted mechanism for this process is the Mass Flow Hypothesis (also known as the Pressure Flow Hypothesis).
- In this mechanism, sucrose is actively transported into the phloem, creating a concentration gradient that allows water to follow by osmosis, resulting in a pressure difference that drives the flow of sap from source to sink.

5. **Conclusion**:
- The food is transported in the form of sucrose from the source (leaves) to the sink (roots or other non-photosynthetic tissues) via the phloem.

**Final Answer**: The food in the form of sucrose is transported by the vascular tissue phloem from a source to a sink.

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