Alexander Templet

Transpiration Rate in Tomato
Solanum lycopersicum

Biology 156
Summer 2008
Mr. Leith Adams, Instructor

Lab Partners:
Michael Adams
Andrew Scalist

Experiments Conducted:
23 June 2008
Abstract
Plants draw water up through their roots and out through their leaves. This process is known as transpiration. The transpiration rate is a major determining factor in how quickly plants absorb water, and is thus critically important to understand for agriculture. In order to study how varying weather conditions affect the rate of transpiration, we conducted experiments using stems of the tomato Solenum lycopersicum. Our results showed increased transpiration when the plants were subjected to wind and also when subjected to light. Interestingly, wind and light combined did not increase transpiration as greatly as light acting alone.

Introduction Plants draw water in through their roots, and then transport it through the xylem up to the branches and leaves. Water exits the leaves through the stomata in the form of water vapor. Polarity causes the water exiting through the stomata to draw after it the water in the xylem, which then pulls in more water through the roots. This process is known as transpiration (Raven et al., 2002). Transpiration is a vitally important process in plants, and to study it further we designed and conducted an experiment to measure the rate of transpiration in the tomato plant, Solenum lycopersicum. In order to study the effects of varying weather conditions on the process, we studied how the transpiration rate would be affected by light, wind, and both light and wind (Vodopich et al., 2002). We hypothesized that these variables would increase the rate of transpiration. Wind can blow water vapor away faster than it would escape normally, and light can increase the plant’s temperature and thus