Sunday, October 19, 2008

Does a saguaro have a brain?

This one at the Arizona-Sonora Desert Museum looks like it does. The prickly brain, however, is just a result of distorted growth. This “monstrose growth” is caused by damage to the meristem, the plant tissue of undifferentiated cells where division into differentiated plant cells occurs. A panel in the Desert Museum explains this odd Carnegiea gigantea shape as follows:
This unusual young saguaro is just beginning to form a crest, which may eventually grow to more than six feet wide. A crest can develop when the growing point or meristem (which produces new stems and spines or leaves), elongates into a line. In time the growing line may become greatly convoluted, like a brain. This phenomenon has been observed in nearly all plant species; its cause is generally not known.
For example, a giant cardon cactus (Pachycereus pringlei) has been found with monstrose growth.

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