Biology Transpiration Practical Essay

Words: 1598
Pages: 7

An experiment proving transpiration in leaves
To see how different environmental conditions affect transpiration of a leaf and which side of the leaf transpires the most.
Background Information
Plants put down roots into the soil to draw water and nutrients up into the stems and leaves. Some of this water is returned to the air by transpiration (when combined with evaporation, the total process is known as evapotranspiration). Transpiration rates vary widely depending on weather conditions, such as temperature, humidity, sunlight availability and intensity, precipitation, soil type and saturation, wind, land slope, and water use and diversion by people. During dry periods, transpiration can contribute to the loss of moisture in the
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4. Use appropriate labels and stick them on thread or on stem of the leaf. 5. Leave the leaves in an undisturbed location. 6. Check the mass of these leaves after a few days.
| Original Masses (g) | Masses after a week (g) | Percentage decrease in mass | Leaf A | 0.41 | 0.30 | 27% | Leaf B | 0.37 | 0.25 | 32% | Leaf C | 0.55 | 0.52 | 5% | Leaf D | 0.44 | 0.40 | 9% |

This is a quantitative experiment.
From the results we gathered, we can conclude that – 1. Leaf B (Top layer covered in Vaseline) – 32% of mass lost 2. Leaf A (Control) – 27% of mass lost 3. Leaf D (Whole plant covered in Vaseline) – 9% of mass lost 4. Leaf C (Bottom layer covered in Vaseline) – 5% of mass lost
Therefore to conclude, we can clearly see that the leaf with the top layer covered in Vaseline lost most water and the leaf with the bottom covered in Vaseline lost the least amount of water.
The ideal ranking of water loss should be – 1. Leaf A (Control) 2. Leaf B (Top layer covered in Vaseline) 3. Leaf C (Bottom layer covered in Vaseline) 4. Leaf D (Whole plant covered in Vaseline)
The control should lose most of its water as none of the stomata on the surface are covered. Even the stalk is not covered. The water should evaporate very easily from the stomata drawing in water from the stalk of the leaf.
The leaf which only has the top layer covered in Vaseline