The purpose of this experiment is to find out if the rate of transpiration in plants can be increased using light and wind. One of the biggest problems that land plants have to deal with is avoiding water loss or desiccation (Whiting, 2011). Transpiration is the loss of water vapor through the stomata (Xu et al. 1995). Transpiration occurs through stomata of leaves and also sometimes occurs in flowers (Vodopich and R. Moore, 2011). During transpiration, the water in the roots is being pulled up through the plant (Xu et al. 1995).
Transpiration serves three important roles in a plant. First, transpiration moves minerals up through the root. It moves minerals in the xylem and the sugars from photosynthesis through the phloem (Whiting, 2011). Water serves as a solvent for moving these vital nutrients through the plant. Second, transpiration helps with the cooling of plants. Most of the cooling effect of plants is caused by the evaporative effect of transpiration (Whiting, 2011). Lastly, transpiration helps with turgor pressure. Water helps maintain the turgor pressure in cells in plants. Turgidity is how plants are able to stay upright and stiff (Whiting, 2011).Turgidity also controls the guard cells, which surround the stomata and regulate water loss and carbon dioxide uptake (Whiting, 2011).
The stomata are epidermal pores in leaves of most plants. They are formed by the separation of a pair of guard cells with a pore in between (Vodopich and R. Moore, 2011). Guard cells in dicots are bean-shaped and are attached to each other at their ends (Vodopich and R. Moore, 2011). The stoma opens depending on by the amount of water between the leaf surface and the air. If the plant is turgid, or filled with water, then the stomata are open which allows gas exchange and loss of water vapor. When the plant loses enough water then the guard cells shrink and close the stomata (Vodopich and R. Moore, 2011).
Transpiration rates are also affected by environmental factors. Temperature and wind velocity will increase transpiration rates because water molecules evaporate quicker (Raven, 2011). Water is conserved when the guard cells are closed. CO2 concentration and light also affect the stomata opening and transpiration rate (Raven, 2011). When CO2 concentrations are high, the guard cells of many plants decrease the stomata opening. Blue light also regulates stomata opening. The blue light triggers proton (H+) transport (Raven, 2011). This signals to begin proton gradient that drives the opening of K+ channels. When K+ pass rapidly out of the guard cells the stomata will close. This is caused by Abscisic acid (ABA) which is a plant hormone (Raven, 2011). When temperatures begin to exceed 30° to 34° C and water conditions are not favorable the stomata will close. Normally, the stomata will open up when it is dark and the temperature has dropped (Raven, 2011).
For this experiment a Creole hybrid tomato plant was used. The experiment...