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  • Potometer
    • Procedure
      • Used to estimate transpiration rates
      • 1) Cut shoot underwater to prevent air from entering xylem. Cut at slant to increase SA available for water uptake
      • 2) Assemble potometer in water and insert shoot underwater so no air can enter
      • 3) Remove apparatus from water, keep end of capillary tube submerged
      • 4) Check apparatus is watertight/ airtight
      • 5) Dry leaves, allow shoot to acclimatise then shut the tap
      • 6) Remove end of capillary tube from beaker of water until one air bubble has formed. Put end of tube back into water
      • 7) Record starting position of air bubble
      • 8) Start stopwatch and record distance moved by bubble per unit time e.g hour. Rate of air bubble movement is an estimate of transpiration rate
      • 9) Only change one variable e.g temp. All other must be kept constant
    • Dissecting plants
      • 1) Use a scalpel to cut cross section of stem. Cut sections as thinly as possible- better for viewing under microscope
      • 2) Use tweezers to gently place cross sections in water until you use them- stops them from drying out
      • 3) Transfer each section into dish containing stain, leave for one minute. Stains lignin in walls of xylem vessels blue-green. Lets you see position of xylem vessels/examine their structure
      • 4) Rinse off sections in water, mount each one onto a slide


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