The limpest lettuce still has a little life left. A new study finds that produce continues to respond to light cues—which enables them to keep protecting themselves from insects and perhaps even enhance their nutritional value to us.

Scientists knew that a favorite test plant called ArabidoIpsis has strong circadian rhythms. Expose Arabidopsis to a set light-dark cycle, and it produces more anti-bug chemicals when it’s lit—which fights off insects living on the same light schedule.

In the new study, researchers tried the light-dark test with store-bought cabbage leaves. The leaves that were on the same light-dark cycle as hungry insects protected themselves more effectively than leaves on cycles out of sync. Other veggies and fruit such as zucchinis and blueberries had similar responses. The study is in the journal Current Biology. [Danielle Goodspeed et al., Postharvest Circadian Entrainment Enhances Crop Pest Resistance and Phytochemical Cycling]

The researchers suggest we try to harvest and preserve produce when its levels of anti-insect chemicals are highest, to help it resist damage. Some of those compounds also reduce cancer risk, so we may enhance our health as well. Circadian appetit!

—Sophie Bushwick

[The above text is a transcript of this podcast.]