DAVIS--Ecologist Rick Karban, professor in the UC Davis Department of Entomology and Nematology, is featured in the Dec. 23-30 edition of The New Yorker in Michael Pollan’s piece, “The Intelligent Plant: Scientists Debate a New Way of Understanding Plants.”

Karban studies volatile (chemical) communication between plants that affect their defenses against herbivores. Pollan wrote that he met Karban in Vancouver, British Columbia, last July when Karban was presenting a paper on “Plant Communication and Kin Recognition in Sagebrush” at the sixth annual meeting of Society for Plant Neurobiology, now the Society for Plant Signalling and Behavior. 

For The New Yorker feature, Pollan interviewed scientists on a number of plant intelligence topics, including decision-making. “Plants perceive competitors and grow away from them,” Karban told Pollan. “They are more leery of actual vegetation than they are of inanimate objects, and they respond to potential competitors before actually being shaded by them.”

Pollan wrote that “Plants speak in a chemical vocabulary we can’t directly perceive or comprehend. The first important discoveries in plant communication were made in the lab in the nineteen-eighties, by isolating plants and their chemical emissions in Plexiglas chambers, but Rick Karban, the U.C. Davis ecologist, and others have set themselves the messier task of studying how plants exchange chemical signals outdoors, in a natural setting.”

Pollan toured Karban’s sagebrush study plot at the UC Sagehen Creek Field Station, near Truckee. Karban has been researching the plant/herbivore interactions since 1999. 

Karban recently drew widespread scientific and media attention with research that he and four colleagues published in February 2013 in the Proceedings of the Royal Society B: Biological Sciences. Their research showed that kin have 
distinct advantages when it comes to plant communication, just as “the ability of many animals to recognize kin has allowed them to evolve diverse cooperative behaviors,” he said in a news release published by the UC Davis Department 
of Entomology and Nematology.

“When sagebrush plants are damaged by their herbivores, they emit volatiles that cause their neighbors to adjust their defenses,” Karban said in the news release. “These adjustments reduce rates of damage and increase growth and survival of the neighbors.”

“Why would plants emit these volatiles which become public information?” he asked. “Our results indicate that the volatile cues are not completely public, that related individuals responded more effectively to the volatiles than did strangers. This bias makes it less likely that emitters will aid strangers and more likely that receivers will respond to relatives.”

The research, “Kin Recognition Affects Plant Communication and Defense,” was co-authored by two scientists from Japan and two from UC Davis: Kaori Shiojiri of the Hakubi Center for Advanced Research, Kyoto University, and Satomi Ishizaki of the Graduate School of Science and Technology, Niigata University; and William Wetzel of the UC Davis Center for Population Biology, and Richard Evans of the UC Davis Department of Plant Sciences. 

To simulate predator damage, the researchers “wounded” the plants by clipping them and then studied the responses to the volatile cues. They found that the plants that received cues from experimentally clipped close relatives experienced less leaf damage over the growing season that those that received cues from clipped neighbors that were more 
distantly related.

“More effective defense adds to a growing list of favorable consequences of kin recognition for plants,” they wrote.

Karban is a fellow of the American Association for the Advancement of Science (AAAS) and has published more than 100 journal articles and two books.

Links:
Kin Recognition Affects Plant Communication and Defense