Leaf and Highest Transpiration Rates

Virtual Lab: Plant Transpiration

Please complete questions below prior to attempting the lab report for this assignment.
Table 1: Total Amount of Water (in mL) Transpired in One Hour
Plant Type Normal Conditions (21oC) With Heater
(27oC) With Fan (21oC) With Lamp (21oC)
Arrowhead 3.6 6.6 7.5 4.0
Coleus 0.9 3.9 6.0 3.0
Devil’s Ivy 2.9 4.1 4.6 3.0
Dieffenbachia 4.1 6.0 7.7 3.9
English Ivy 1.8 3.2 5.1 2.1
Geranium 1.2 5.8 4.7 2.4
Rubber Plant 4.9 6.8 8.4 4.3
Weeping Plant 3.3 4.9 6.1 2.5
Zebra Plant 4.2 6.1 7.6 3.2

1. Define transpiration.

The process by which moisture is carried through plants.

2. Based on the results from your lab, how might your results differ if you direct the air flow onto the upper surface of the leaf versus the lower surface? Why?

3. Did any of the environmental factors (heat, light, or wind) increase the transpiration rate more than the others? Why?

The transportation was increased mostly by the fan: 6.4 As it increased the respiration by transporting water away from plant.

4. Which species of plants that you tested had the highest transpiration rates? Why do you think different species of plants transpire at different rates?

The plant that was observed with the highest rate of transportation is the rubber plant. Also, each plant species has a rate of transportation, good for its domestic environment. As higher transportation rates could be an indicator of a more wet climate. And lower rate of transportation could be used to conserve water in hotter climates.

5. Describe the pathway of water movement from xylem cells in the stem to the air surrounding the leaf.

6. What is the role of the roots and root hairs in transpiration?

7. With intense sunlight, drought, and intense wind a plant’s guard cells may lose turgor pressure and its stoma may close.
a. What is an advantage of a plant’s stoma closing?
b. What is a disadvantage of a plant’s stoma closing?

8. Explain the purpose of each of the following structures with regard to transpiration:
a. Cuticle -
b. Guard cells -
c. Trichomes -

9. Beside each of the following terms, write out whether it describes collenchyma, parenchyma, or sclerenchyma cells.

found in stems - thin-walled, many-sided cells - dead at maturity - contain lignin - thick-walled, irregularly shaped - photosynthetic cells -

10. Are the number of stomata on the underside of a leaf more, less, or the same as on the upper surface of a leaf? 11. When you receive a bouquet of flowers, it is recommended that you cut a couple of inches off of the stems before placing them in a vase. Why do you think this is?

12. Explain why vessel elements would have no need for companion cells.
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13. Identify the properties of water that assist water transport in xylem.

14. Explain the process in which sugars move from source to sink in a plant.

15. Describe the cohesion-tension model in detail.
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