Which plant part typically contains the highest cyanide content?

• A. Seeds
• B. Leaves
• C. Bark
• D. Seeds, leaves, and bark (highest)

Answer: (D)

Cyanogenic compounds are concentrated unevenly in plants to defend against herbivores, with tissues that are most likely to be damaged or consumed often carrying the most. Seeds are a key target for protection of the next generation, so they frequently hold high levels of cyanogenic glycosides. Leaves and bark also commonly contain substantial amounts to deter feeding and invasion. When these tissues are damaged, enzymes hydrolyze the glycosides and rapidly release hydrogen cyanide, increasing toxicity risk. Because seeds, leaves, and bark together tend to have the highest levels across many cyanogenic plants, this option best reflects the typical distribution. (Some species can have high cyanide in other parts like roots, but the combination of seeds, leaves, and bark is most often the highest.)