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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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