Which of the following is not correct regarding translocation of food in plants?

Options

A. In food transport the source - sink the relationship is variable depending on the season or the plant's need.
B. Phloem sap consists of mainly water and sucrose, but other sugers, hormones and amino acids are also translocated through the phloem.
C. In sugar utilising sink cells, the osmotic pressure must be very high so that they can get water along with sugar from the phloem
D. Active transport is required for the process of loading and unloading of sugar.

Answer

To determine which statement is not correct regarding the translocation of food in plants, let's analyze each option step by step.

### Step 1: Understanding Translocation of Food
Translocation in plants refers to the movement of nutrients, particularly sugars, from the source (where they are produced, typically in the leaves) to the sink (where they are used or stored, such as roots, fruits, and seeds). This process primarily occurs through the phloem.

### Step 2: Evaluating the Statements
1. **Statement 1**: "In food transport, the sourcing relationship is variable depending on the season or the plant's need."
- This statement is **correct**. The source and sink can change based on the plant's growth stage and seasonal changes.

2. **Statement 2**: "Phloem sap consists mainly of water and sucrose, but other sugars like hormones or amino acids are also translocated through the phloem."
- This statement is **incorrect** as it implies that phloem sap only consists of water and sucrose. In reality, phloem sap contains not just sucrose but also amino acids, organic acids, and other solutes. Therefore, this statement is misleading.

3. **Statement 3**: "In sugar-utilizing sink cells, the osmotic pressure must be very high so they can get water along with the sugar from the phloem."
- This statement is **correct**. High osmotic pressure in sink cells helps draw water from the phloem, facilitating the movement of sugars into these cells.

4. **Statement 4**: "Active transport is required for the process of loading and unloading of sugar."
- This statement is **correct**. The loading of sugars into the phloem and unloading at the sink often requires active transport mechanisms.

### Conclusion
The statement that is not correct regarding translocation of food in plants is **Statement 2**.

### Final Answer
The incorrect statement regarding translocation of food in plants is **Option 2**.

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