Fruits and Vegetables Are Alive

Okay, we knew on one level that fruits and vegetables are still "alive," because we can grow a new plant from just a piece of celery, carrot, or potato from the produce market. But a new study throws a different light on the concept of "life," as far as plants are concerned.

A study published online today in the journal Current Biology found that store-bought cabbage, lettuce, spinach, zucchini, sweet potatoes, carrots, and blueberries respond to light-dark cycles up to about a week after harvest.

And when the produce was kept on the same light-dark cycle as a predator—cabbage looper moth caterpillars (Trichoplusia ni)—it was better able to resist attacks.

Circadian clocks tell plants when the seasons change due to variations in day length, said Janet Braam, a plant biologist at Rice University in Houston, Texas. But the clock is also critical in plant defenses against insects.

"[Plants] know when the insects eat," said Braam, who is a co-author on the recent study, "so they can prepare a defense in advance."

Thinking about this led me to wonder if scientists can take individual cells from fruit and determine whether they are still alive. And when do they really die? Two weeks in the refrigerator? When we cut them? Or when we cook or eat them? Thinking along these lines can lead to nightmares. Read more about the study at NatGeo News.