Effect of Osmosis on Plant Tissue

• Osmosis


  Diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
• Plant cells placed in water


  Water moves into the cell by osmosis, causing the cell to expand
• Plant cells placed in concentrated solution


  Water moves out of the plant cell by osmosis, causing the cell to shrink
• Investigating the effect of osmosis on plant tissue

  1. Peel potato

  2. Use cork board to produce cylinders of equal diameter

  3. Trim cylinders to equal length

  4. Measure length and mass of cylinders

  5. Place cylinders in test tubes with different solutions (0.5M sugar, 2.5M sugar, distilled water)

  6. Leave overnight

  7. Remove cylinders, gently roll on paper towel to remove surface moisture

  8. Measure length and mass of cylinders again
• Percentage change


  Calculated as: (Change in value / Original value) x 100
• Calculating percentage change


  • Potato cylinder starting mass 1.56g, increases by 0.25g - Percentage change = (+16.03%)
  • Potato cylinder starting mass 1.32g, decreases by 0.19g - Percentage change = (-14.39%)
• Concentration of sugar solution


  Affects percentage change in mass/length of potato cylinder
• In water, potato cylinder gains mass as water moves in by osmosis. In concentrated sugar solution, cylinder loses mass as water moves out by osmosis. Where line crosses x-axis, no change in mass as concentration outside cell is same as inside.