Ripening bananas emit the gas ethylene, known as the “aging hormone,” reports

In plants, research has shown that environmental cues like temperature and sunlight regulate circadian cycles. However, put a plant in a dark cupboard, and many of these day-night processes continue. But how? Researchers like Dr Haydon are fascinated by this mystery.

“The earliest reported experiments demonstrating circadian rhythms in complete darkness were done in plants in the 18th century,” he says.

“These biological rhythms have evolved multiple times, in plants, animals and other organisms, so they are clearly important.”