Carol Puls, age 11, of Jackson, Missouri, for her question:

Do plants sleep?

Sometime ago Andy explained that all plants take rest periods. We cannot spy that trees shed .their leaves and hibernate through the winter because the word hibernation belongs to the animal world. We say that they go through a dormant period of rest. True, we say that the winter woods are sleeping, but this is merely a poetic expression. In order to go to sleep, a creature must be able to wake up. And so far as we know, the plants do not have alert conscious minds.

All through the sunlight hours, green plants are very busy manufacturing their basic, sugary plant food. The activity stops when the sun goes down. But at night the green plants don't even rest. Instead, they change their chemical activities and get busy with other chores. During the night, they convert their basic sugary food into the dozens of complex chemicals needed to build new growth. Through the summer growing season plants never rest day or night    but they do shut down operations and take a long rest during the winter.