-------- Original Message -------- Subject: Re: [ECOLOG-L] Plant/Gall cooling Date: Tue, 17 Apr 2012 17:05:14 -0800 From: Syndonia Bret-Harte <[email protected]> Organization: University of Alaska, Fairbanks To: R. Malia Fincher <[email protected]>
Hi Malia, Leaves cooling below ambient temperature is a well-known phenomenon in plant physiology, and indeed, you can experience it for yourself if you touch the leaves of a well-watered plant in a relatively low light environment (such as a plant growing in a restaurant - real plants feel cool, while plastic plants are the same temperature as the air). Plants can indeed cool their leaves below ambient temperature by evaporation as they transpire. Whether they cool below air temperature, or just below what they would be without evaporative cooling, depends on the radiation load experienced by the leaf. Park Nobel in his textbook Physicochemical and Environmental Plant Physiology has a whole chapter on the temperature and energy budgets of leaves, which explains the factors involved in this response. I would doubt that insect galls would cool themselves, because the cooling depends on transpiration by the leaf, and the galls are unlikely to transpire. Hope this helps, take care, Syndonia On 4/17/12 8:35 AM, R. Malia Fincher wrote:
I have been unsuccessfully (but briefly) searching the literature for incidences of plants and/or galls on plants cooling themselves substantially below ambient temperature. I have run across a fungal gall, with an associated gall midge larva, that is 6-10 degrees C colder than normal leaves and the ambient air temperature. I am aware of the capacity of certain plants to warm themselves, but this is the first time that I have encountered cooling. Is anyone familiar with such a phenomenon? Thank you, Malia R. Malia Fincher, Ph.D. Assistant Professor Samford University Department of Biological and Environmental Science 800 Lakeshore Drive Birmingham, Alabama35229 [email protected] 205-726-2928 Fax 205-726-2479 Office 133 Propst Hall
-- ******************************************************* Dr. M. Syndonia Bret-Harte Associate Professor of Biology and Wildlife Associate Science Director, Toolik Field Station Institute of Arctic Biology University of Alaska, Fairbanks PO Box 757000 Fairbanks, AK 99775-7000 907-474-5434 http://users.iab.uaf.edu/~syndonia_bret-harte/CV.html and http://users.iab.uaf.edu/~syndonia_bret-harte/ email address:<[email protected]>
