Choose the correct statement about haustorial (Parasitic) roots of Cuscuta.

Options

A. These roots develop contact with xylem of host.
B. These develop contact with phloem of host to get food.
C. These develop contact with pericycle and lateral roots of host
D. Both A and B

Answer

To solve the question regarding the haustorial (parasitic) roots of Cuscuta, we will follow these steps:

### Step-by-Step Solution:

1. **Understand the Nature of Cuscuta**:
- Cuscuta, commonly known as dodder, is a total stem parasite. This means that it relies entirely on its host for both nutrients and water.

2. **Define Haustorial Roots**:
- Haustorial roots are specialized structures that penetrate the host plant's tissues to extract water and nutrients. In the case of Cuscuta, these roots are adapted to connect with the host plant's vascular system.

3. **Types of Parasites**:
- Parasites can be classified into two categories:
- **Semi-parasitic (partial) parasites**: These can photosynthesize and produce some of their own food but still depend on the host for water.
- **Total parasites**: These cannot photosynthesize and rely completely on the host for both food and water.

4. **Identify the Function of Haustoria in Cuscuta**:
- The haustoria of Cuscuta penetrate both the xylem and phloem of the host plant. This allows Cuscuta to extract water from the xylem and nutrients (food) from the phloem.

5. **Evaluate the Given Statements**:
- **Option A**: "These roots develop contact with xylem of host." - This is partially correct, but incomplete since Cuscuta also connects with phloem.
- **Option B**: "These develop contact with phloem host to get food." - This is also partially correct, but again incomplete as it neglects the xylem connection.
- **Option C**: "These develop contact with pericycle and lateral root of host." - This is incorrect as the haustoria do not primarily interact with these structures.
- **Option D**: "A and B." - This is the correct option as it acknowledges that Cuscuta haustoria connect with both xylem and phloem.

6. **Conclusion**:
- The correct answer is **Option D (A and B)**, as Cuscuta's haustorial roots develop contact with both the xylem and phloem of the host plant.