Y'all:
I wonder what effect, if any, that soil temperature and root depth might
have differentially with ambient surface atmospheric temperatures? That is,
soil temperatures can be warmer than surface atmospheric temperatures, and
if active solute transport is going on the temperature differential might be
affected? Also, there is the chemical composition of the protoplasm and
temperature differentials due to sun exposure, wind speed, etc., no?
Just casting about . . .
WT
----- Original Message -----
From: "Martin Meiss" <[email protected]>
To: <[email protected]>
Sent: Tuesday, April 17, 2012 1:56 PM
Subject: Re: [ECOLOG-L] Plant/Gall cooling
Actually, evaporative cooling does not necessarily bring leaf temperature
below ambient temperature. Because the leaf is absorbing light, it may
be,
say, 10 degrees warmer than the surrounding air. Depending on the
details,
the evaporative cooling may be able to bring this down only to perhaps 5
degrees WARMER than the surrounding air, or under other circumstances,
perhaps 5 degrees COOLER than the air. As a generality, all we can say is
that the evaporative cooling makes the leaf cooler than it would be if
there were no evaporative cooling.
Martin M. Meiss
2012/4/17 Don Cipollini <[email protected]>
Malia,
If I am reading your question correctly, any plant that is undergoing
evapotranspiration typically experiences evaporative cooling and will be
below ambient temperatures while this is occurring. Perturbations in
this
effect, such as during drought-induced stomatal closure, can lead to heat
build-up and subsequent negative effects on photosynthesis. Whether
galling induces additional cooling effects beyond what is experienced by
a
"normal" leaf experiencing evaporative cooling is unknown to me, but
would
seemingly require some increase in evapotranspiration in galled leaves.
This might be expected for some gallers, but unexpected for others,
depending on hormonal changes in galled leaves (e.g. whether changes in
hormones like ABA would be expected). It would seemingly be adaptive for
gallers to help "cool" their host leaves, lest they be exposed to high
temperatures, while it might be adaptive for plants to bake their gallers
by locally reducing evaporative cooling in galled leaves.
Don
On 4/17/2012 12:35 PM, 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
--
*************************************
Don Cipollini, Ph.D.
Professor- Plant Physiology/Chemical Ecology
Director- Environmental Sciences PhD Program
Department of Biological Sciences
Wright State University
3640 Colonel Glenn Highway
Dayton, Ohio 45435-0001
(937) 775-3805
FAX (937) 775-3320
email: [email protected]
Lab Page:
http://www.wright.edu/~don.**cipollini<http://www.wright.edu/%7Edon.cipollini>
Env Sci PhD Program:
http://www.wright.edu/**academics/envsci/<http://www.wright.edu/academics/envsci/>
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