Ethylene
ETH-uh-leen🔬 Anatomy●● Intermediate
Also known as: ripening hormone
Ethylene is the only gaseous plant hormone. Ripening fruits release ethylene, which triggers ripening in nearby fruit (why one bad apple spoils the bunch). Plants also produce ethylene in response to stress, wounding, and flooding. Commercial growers use ethylene gas to ripen tomatoes harvested at the breaker stage.