Temi OladejiTanspiration of a Plant LabPartner(s): Suad Musse, Arij Al khafagiDate: 16thJanuary 2016
PURPOSE:The purpose of the transpiration rate of a plant lab is to examine the rates of respirationof plants in various conditions.THEORY: In plants, the xylem is involved in the transport of water, that is absorbed by the roots, and travels up the stems by the xylem vessels. These vessels are in the vascular bundles of the plant,and the loss of water vapour from the leaves and stems of a plant is known as transpiration. Water is often loss due to evaporation through the stomata, which allows for gas exchange in the leaf. Transpiration is controlled by a pair of guard cells surrounding each stomamta, whiich can change shape, and guard cells open when they gain potassium ions and water from the surrounding cells. Water evaporates off a leaf's surface, moving from an area of high water potential to an area of low water potential, however, there are many environmental factors that affect transpiration in plants including;•Light: which controls the opening and closing of the stomata, a large amount of light means that the stomata's will be more open; this will increase the transpiration rate. In this experiment, light will be one of the environmental factors experimented with.•Temperature:high temperatures speed up the reaction rate, therefore as temperature increases , the rate of transpiration also increases. This factor will not be tested in this experiment, however, we can discuss how the temperature of the classroom affected the transpiration of our plants.•Humidity: If the concentration of water outside a plant is higher than inside, the water does not want to go into the plant. Therefore, as humidity increases, the rate of transpiration will actually decrease.•Wind: As the wind blows away air droplets, the plant will attempt to intake more water; therefore as air current increases, the rate of transpiration also increases.APPARATUS: Exacto KnifeA short black rubber tubePlatic BagBean PlantA small white funnelA FanA large funnel clampDistilled WaterA misterA small funnel clampPlastic WrapA TimerA long clear tube200 watt Flood LightTubeing Grease
PROCEDURE:1.Using a sharpened razorblade, cut a branch of the bean plant at a diagonal, and be sure to include some of the stem.2.Determine the surface area of the leaves by tracing each of the leaf outline onto a piece of grid paper. Also, place the branch into water when it is not being used to keep it from drying out.