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 transiocated 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 solve the question regarding which statement is not correct about the translocation of food in plants, we can follow these steps:

### Step 1: Understand Translocation
Translocation in plants refers to the movement of food (mainly in the form of sucrose) and other nutrients from the leaves, where they are produced during photosynthesis, to other parts of the plant, such as stems and roots.

**Hint:** Recall that translocation is primarily associated with the movement of sugars and nutrients from the source (leaves) to the sink (other parts of the plant).

### Step 2: Analyze Each Statement
We need to evaluate each of the four statements provided in the question to determine which one is incorrect.

1. **Statement 1:** "In food transport, the source-sink relationship varies depending upon the season or the plant's need."
- This statement is correct. The source-sink relationship changes based on the plant's growth stage and environmental conditions.

**Hint:** Think about how plants allocate resources based on their developmental needs and environmental factors.

2. **Statement 2:** "Phloem sap consists of mainly water and sucrose, but other sugars, hormones, and amino acids are also translocated through the phloem."
- This statement is incorrect. Phloem sap primarily consists of sugars (like sucrose), hormones, and amino acids, but it does not contain a significant amount of water. Water is mainly transported through xylem.

**Hint:** Remember the composition of phloem sap versus xylem sap.

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

**Hint:** Consider the role of osmotic pressure in the movement of water and nutrients in plants.

4. **Statement 4:** "Active transport is required for the process of loading and unloading of sugar."
- This statement is also correct. Active transport mechanisms are indeed involved in loading sugars into the phloem and unloading them at the sink.

**Hint:** Recall the role of active transport in moving substances against their concentration gradient.

### Step 3: Identify the Incorrect Statement
After analyzing all the statements, we can conclude that the second statement is the one that is not correct regarding translocation of food in plants.

**Final Answer:** The incorrect statement is **B**: "Phloem sap consists of mainly water and sucrose but other sugars, hormones, and amino acids are also translocated through the phloem."