research.gif (2985 bytes) Dr. Gary Coté, Professor of Biology

Effects of Herbivory and Stress Hormones on Crystal Idioblasts

One major hypothesis about the role of crystal idioblasts is that they deter herbivores from eating the plant.  If this is true, one might expect that plants would make more crystals when something has been chewing on it.  Alternately, hormones that signal stress in a plant might increase the number of crystals, protecting a plant when it is most vulnerable. 
To test this we simulated herbivory by chewing up the plant's leaves with forceps or a paper punch and looking for changes in the number of crystal idioblasts.  We also sprayed the plants with various stress hormones and similarly looked for changes in the number of crystal idioblasts.  Above right, Matt Ryan is posing with plants he has sprayed with a volatile hormone, jasmonic acid, and then sealed into plastic bags to keep the hormone in.

This project involved a tremendous amount of work and the processing of an enormous number of samples (below, samples in process on a rotary shaker).  Chris Gowdy, Natasha Brooks, Matt Ryan, Adam Woodson, Mike deMilt, Jason Crolley, and Andrea McConnachie all contributed to this project.  The results are still in process, but it appears that Dieffenbachia does not regulate its idioblast number in response to herbivory or other stress.

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