Also remember that CO2 disolves into water to form H2CO3 (carbonic acid). The
pH change within the leaf tissue might also have an effect. CO2 is known to
be involved in stomatal closure, it may just be involved in trap closure! I
checked my CP books, and found nothing about pH effetcs. It's probably not a
simple one factor one rection relationship, but a chain of reactions leading to
closure.
Just my two U.S. cents worth.
Jeff in ol' East Lansing, where Michigan State U is deserted due to Spring
Break (Fruhjahrreisen)