cyanide poisoning in plants?

Question

If you poison a plant with cyanide, I know that it blocks cellular respiration. But how? Does it do something to the stomata or the mitochondria?

Answer 1

Cyanide is an irreversible enzyme inhibitor. Cyanide ions bind to the iron atom of the enzyme cytochrome c oxidase (also known as aa3) in the fourth complex in the mitochondrial membrane in the mitochondria of cells. This denatures the enzyme, and the final transport of electrons from cytochrome c oxidase to oxygen cannot be completed. As a result, the electron transport chain is disrupted, meaning that the cell can no longer aerobically produce ATP for energy.

Tissues that mainly depend on aerobic respiration, such as the central nervous system and the heart, are particularly affected.

Plants contain an alternative pathway for respiration in their mitochondria. The alternate oxidase is not as efficient as the normal pathway, but immune to cyanide. As a result, plants are insensitive to concentrations of cyanide that are lethal to animals, and a few species (e.g. the Giant Bamboo in its shoots) are known to contain cyanides.Interestingly, the Greater Bamboo Lemur is able to consume lethal doses of the Giant Bamboo shoots with no effect. The reason for its immunity is not yet understood.