Transpiration Lab Write-up.
Transpiration is the evaporation of water from plants. It’s not simply a hazard of plant life but it’s the engine that pulls water from the roots to cool the leaf and supply photosynthesis. The concentration of water vapor in the atmosphere is lower than that in the leaf. Because of this difference, water vapor diffuses from the spaces of the leaf, through the stomata in the epidermis. Stomata are in the lower epidermis; the lower surface receives less radiation from the sun that’s why it reduces water loss (Sadava 2010). Each stoma allows carbon dioxide to enter for photosynthesis white water evaporates through each one in transpiration. The plant uses transpiration to pull the water up against gravity. Water can be pulled upward through tiny tubes because of the remarkable cohesion of water so that they form a continuous stream extending from leaves to root. The integrity of the column is also maintained by the adhesion of water to the xylem walls (Pidwirny, 2006). These are important facts because when water is sticking together it means more water is pulled up the stem to replace the water loss. Evaporation is the process of water changing from a liquid into a gas (Pidwirny, 2006). Transpiration is the evaporation of water from a plant’s flowers, stem or leaves back into the atmosphere. That’s how they are linked together. The question is what factors affect transpiration? The environmental factors that affect the rate of transpiration are light, temperature, humidity, wind and soil water (Sadava, 2010). In lab 3b, all of the plants in this experiment will lose a lot of water through transpiration, but those affected by the light and the fan will lose a larger amount of water. Then the hypothesis can be factors that increase evaporation will increase transpiration. Plants transpire actively in the light than in the dark, lights also speeds up transpiration by warming the leaf. When there’s no wind...
Cited: David Sadava & May R. Berenbaum (July 2010). Life the Science of Biology (9th Ed). MA
Plants and Soil Sciences eLibrary (2012) Transpiration-Water movement through plants. Retrieved Sept 14, 2012 from
Pidwirny, M (2006) Physical Geography Evaporation and Transpiration. Retrieved Sept 14, 2012 from
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