Seed biology: “Recalcitrant seeds” are best described as which of the following with respect to drying and low-temperature storage?

Introduction / Context:
Seeds are often classified as orthodox or recalcitrant based on their tolerance to desiccation and storage conditions. Understanding this distinction is crucial in conservation, genebanking, and nursery operations.

Given Data / Assumptions:

• Orthodox seeds tolerate drying and can be stored at low moisture and temperature for long periods.
• Recalcitrant seeds are typically from tropical or subtropical species.
• Cellular damage in recalcitrant seeds occurs on dehydration and freezing.

Concept / Approach:
Recalcitrant seeds remain metabolically active, have high moisture content, and lack mechanisms to survive desiccation. Ice crystal formation at subzero temperatures and membrane damage during water loss reduce viability, making conventional seed banking unsuitable.

Step-by-Step Solution:

Verification / Alternative check:
Species such as cocoa, mango, and many forest trees exhibit sharp viability declines upon desiccation or low-temperature storage.

Why Other Options Are Wrong:

• A/D: Opposite of the definition; recalcitrant seeds are not resistant and are affected.
• C: While sensitivity varies in degree, the class is defined by sensitivity, not resistance.
• E: Irrelevant to the standard classification.

Common Pitfalls:
Assuming all seeds store like cereals; overlooking moisture content parameters leads to viability loss.

Final Answer:
Killed by drying and freezing temperatures