Orthodox seeds can be preserved for long periods at a temperature of

Options

A. `-196^@C`
B. `-10^@ " to " -20^@C`
C. `0^@ - 4^@C`
D. `10^@ " to " 15^@C`

Answer

To solve the question about the preservation of orthodox seeds, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Orthodox Seeds**:
- Orthodox seeds are seeds that can survive drying and freezing. They are capable of being preserved for long periods under suitable conditions.

2. **Comparison with Recalcitrant Seeds**:
- Unlike orthodox seeds, recalcitrant seeds cannot withstand desiccation and have a shorter shelf life. This distinction is important when discussing preservation methods.

3. **Temperature Range for Preservation**:
- Orthodox seeds can be preserved at low temperatures. The ideal temperature range for long-term preservation of these seeds is between -10°C to -20°C.

4. **Optimal Temperature**:
- The optimal temperature for maintaining the vigor and viability of orthodox seeds is approximately -18°C. This temperature helps in increasing the storage life of the seeds.

5. **Evaluating Options**:
- Given the options provided:
- -196°C (too low)
- -10°C to -20°C (includes -18°C)
- 0°C to 4°C (too high)
- 10°C to 15°C (too high)
- The correct answer would be the range that includes -18°C, which is -10°C to -20°C.

6. **Conclusion**:
- Therefore, the correct answer to the question is that orthodox seeds can be preserved for long periods at a temperature of **-10°C to -20°C**.