section 3 - plant nutrition and transport

• Photosynthesis


  1. Carbon dioxide + water

  2. Glucose + oxygen
• Photosynthesis (chemical symbol equation)


  • 6CO2 + H2O
  • C6H12O6 + O2
• Leaf adaptations for photosynthesis


  • Broad so large surface area for light
  • Chloroplasts in the palisade layer where can get most light
  • Upper epidermis is transparent so light can pass through
  • Leaf is thin so quick diffusion of gases
• Factors that affect the rate of photosynthesis


  • Light
  • Carbon dioxide
  • Temperature
• Limiting factor


  Stops photosynthesis
• In photosynthesis plants make glucose that is stored as starch
• If a plant does photosynthesize it will have starch, if it does not photosynthesize it will not as starch is used up
• Test a leaf for starch


  1. Put leaf in boiling water

  2. Put leaf in ethanol

  3. Rinse leaf and place on spotting tile

  4. Add 3 drops of iodine

  5. Repeat 3 times
• Test if chlorophyll is needed for photosynthesis (variegated leaf)


  1. Repeat test leaf for starch method

  2. Green part of leaf will test for starch

  3. White part of leaf has no chlorophyll so will test negative for starch
• Test if CO2 is needed for photosynthesis


  1. Place plant in sealed bell jar with soda lime

  2. Test leaf for starch
• Test if light is needed for photosynthesis


  1. Place plant in dark for 24 hours or cover part of a leaf for 24 hours

  2. Test leaf for starch
• Test the rate of photosynthesis using a water plant

  1. Count the number of bubbles in one minute

  2. Change the distance of the light and count the bubbles produced
• Xylem


  Transports water and minerals up the plant
• Phloem


  Transports glucose and amino acids up and down the plant (translocation)
• Root hair cells


  • Adapted to absorbing water from the soil as they have a large surface area
• Transpiration


  The loss of water from a plant caused by evaporation and diffusion at the leaves
• Factors affecting the rate of transpiration


  • Light intensity (higher, the faster)
  • Temperature (higher, the faster)
  • Wind speed (higher, the faster)
  • Humidity (the lower, the faster)
• Estimate the rate of transpiration

  1. Cut slant shoot underwater

  2. Set up the potometer underwater and insert shoot

  3. Measure the distance covered by the air bubble and time taken

  4. Keep temperature the same

  5. Repeat three times