2.56: Describe Experiments to Investigate the Role of Environmental Factors in Determining the Rate of Transpiration from a Leafy Shoot

TRANSPIRATION: Evaporation of Water from the Surface of the Plant

POTOMETER: Can be Used to Measure the Volume of Water Absorbed by the Plant

INVESTIGATING ENVIRONMENTAL FACTORS ON RATE OF TRANSPIRATION

Diagram Showing a Plant in a Potometer to Measure Water Uptake of Plant

METHOD: Cut a Shoot Underwater to Prevent Air Entering the Xylem and Place in Tube Set up the Apparatus as Shown in the Diagram and Make Sure it is Airtight Remove Capillary Tube from the Beaker of Water to Allow a Single Air Bubble to Form and Place the Tube Back into the Water Record the Starting Distance of the Air Bubble Set Up the Environmental Factor you are Investigating Allow the Plant to Adapt to the New Environment for 5 Minutes Measure Final Distance of Air Bubble (Volume of Water Absorbed by Plant can be Calculated) Change the Intensity or Level of Environmental Factor being Investigated

RESULTS The More Volume of Water Absorbed, the Higher the Rate of Transpiration as this means that Water Molecules are Pulling Each other Up the Xylem Vessels and through the Spongy Mesophyll Cells by Osmosis Water Molecules will Evaporate and Form Water Vapors and will Diffuse Out of the Stomata of the Leaf The Constant Absorption of Water will Continue this Process

ENVIRONMENTAL FACTORS: Temperature : Temperature of Room (Cold Room and Warm Room) Humidity : Spray Water in Plastic bag and Wrap Around Plant Wind : Distance of Fan to Plant Light Intensity : Distance of Lamp to Plant