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Measure Transpiration
Name: Catherine
Status: other
Age: 50s
Location: N/A
Country: N/A
Date: 12/7/2004
Question:
In an experiment attempting to measure leaf
transpiration, we are looking at how leaf texture effects
transpiration - waxy as opposed to fuzzy leaves. Do we need to try to
make the
total surface area of leaves from the different plants equal to each
other?
Replies:
This is an excellent experiment. You don't necessarily need to
make total leaf surface areas equal but you do need to measure those
surface areas, because transpiration should be expressed per surface
area (typically in mg m-2 s-1 or g m-2 h-1). The numbers in those last
parentheses should be superscripts.
Also, you should be mindful of the fact that many other factors
besides leaf texture have strong effects on transpiration. These
include leaf morphology factors such as stomatal density, leaf size, and
leaf shape; leaf physiology factors such as stomatal responses to light,
temperature, and humidity; and environmental conditions such as light,
temp, humidity, and wind speed. You should try to control these
variables. You also will find that time of day has a very strong effect
on transpiration, as many plants have their stomata open only in the
morning - this is especially true of plants adapted to very dry
conditions.
Christopher Perkins
Leaf texture usually refers to leathery, papery, or membranous; while
"fuzzy" leaves refers to the indumentum, i.e., the hairs on the leaf, and
other structures, e.g., glands. Can refer to a plant physiology text for both.
Possibly helpful:
http://users.gsat.net.au/wildog/rhodotree.html
http://www.amjbot.org/cgi/content/full/88/8/1371
http://www.botany.org/ajb/00029122_di001816.html
Anthony Brach PhD.
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Update: June 2012
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