Seed i.e. positive photoblastic is

Options

A. Tobacco
B. Onion
C. Lily
D. Phlox

Answer

To determine which seed is positive photoblastic, we need to understand the concept of photoblastism in seeds. Here’s a step-by-step solution:

### Step 1: Understand Photoblastism
Photoblastism refers to the response of seeds to light during germination. Seeds can be classified into two categories based on their light requirements:
- **Positive photoblastic seeds**: These seeds require light for germination. Their germination is stimulated by exposure to light.
- **Negative photoblastic seeds**: These seeds do not require light for germination and may even have inhibited germination in light.

### Step 2: Analyze the Options
The options given in the question are:
- A) Tobacco
- B) Onion
- C) Lily
- D) Flax

### Step 3: Identify Positive Photoblastic Seeds
We need to identify which of the options is known to be a positive photoblastic seed.
- **Tobacco**: This is a well-known example of a positive photoblastic seed. It requires light for germination.
- **Onion**: Generally, onion seeds are not classified as positive photoblastic.
- **Lily**: Lilies typically do not require light for germination, making them negative photoblastic.
- **Flax**: Flax seeds also do not have a light requirement for germination.

### Step 4: Conclusion
Based on the analysis, the only seed among the options that is classified as positive photoblastic is **Tobacco** (Option A).

### Final Answer
The seed that is positive photoblastic is **Option A: Tobacco**.

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