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Karban and his team have found that communication among sagebrush plants is most effective early in the growing season, when the plants are growing actively and have the most access to water. As droughts become more severe and more common, plants may not be able to communicate as effectively and may be less able to defend themselves as a result....
In the past 15 years or so, thanks to advances in plant genetics and a new openness toward plant research once considered fringe, botanists such as Karban have found that plants produce and respond to complex chemical signals. They can detect the slightest touch. They know when they’re shaded by a cloud or a fellow plant, and whether that plant is related to them. Several species can recognize their genetic kin and rearrange their bodies to avoid competing with siblings. They can manipulate predators to do their bidding and transmit electrical signals among their roots. One paper suggests that some may perform arithmetic division to keep from starving at night, when they can’t perform photosynthesis.