tube, and knocking out any gas bubbles before taking note of the calibrated mark on the pipette. ii. iii. Set up the lamp 7 cm away from the potometer. iv. Turn the lamp on and begin recording the reading of the pipette every 5 minutes, taking note of the difference between each reading. v. Clean up. c. Data Table i. Time (mins) Reading (mL) Difference in Readings (mL) 0 0.10 N/A 5 0.10 0 10 0.10 0 15 0.11 0.01 20 0.12 0.01 25 0.15 0.03 d. Analysis [see Calculations ] e. Conclusion [see Evaluating Results ] ● Hypothesis: a. The rate of transpiration will be greater when the plant is exposed to concentrated light than when it is in a controlled environment.
Calculations 1. Total surface area of leaves: 113.75 cm 2 2. Rate of transpiration: .12 ml in 20 min—->0.006mL/min 3. Adjusted rate of transpiration:  4. Graph of class results:  Analyzing results ● Answers to questions 1. The rate of transpiration remained the same as compared to the control. 2. Transpiration can be affected by temperature, light, humidity, wind, etc, which in turn can speed up or slow down transpiration rates. 3. Based on the data collected from different lab groups, decreasing the temperature by adding ice around the plant resulted in the greatest rate of water loss through transpiration. This is likely the case because as it gets colder in the environment, the plants close up their stomata and absorb more water. 4. We needed to calculate leaf surface area to determine the rate(s) of transpiration because the leaf surface area helps estimate the number of stomata, which could slow down or speed up the rate of transpiration. The more surface area of the leaf is present, the more transpiration occurs. 5. Structural and physiological adaptations that enable plants to control water loss include stomata, cuticles, foliage, leaves which affect transpiration by decreasing the number of stomata to reduce water loss, thickening cuticles to slow transpiration, light/grey foliage to reflect light and lower temperature inside the leaf, thicker leaves to store water and conserve it.
You've reached the end of your free preview.
Want to read all 7 pages?
- Fall '18
- Photosynthesis, lab, AP Biology, Transpiration, 5 minutes, 1 mm, 0.006mL