Experiment 1. When there is cool wind blowing over the leaves, the transpirational rate will not change significantly because the temperature remains low. When there is hot wind blowing over the leaves, the transpirational rate will increase because the higher temperature will cause increased loss of water through the stomata. And finally, when there is a higher relative humidity, the transpiration rate will decrease because of the excess moisture in the environment. For Experiment 2, my hypothesis is that dicot plant species will have the highest stomata density because they have a more extensive mechanism of survival, while monocots will have the least. Finally, for Experiment 3, my hypothesis is that small leaves will have more major veins than large leaves which will allow them to better survive under conditions of drought. Methods In Experiment 1, we used California shrub species Heteromeles arbutifolia . We cut the stem underwater to prevent water loss during preparation of this experiment. We used a potometer, a plastic tubing, and connected it to the stem of the plant under water. After equilibrating the potometer for 5 minutes, we marked the water level on the tube with a sharpie every 5 minutes for a total of 15 minutes. These steps were repeated four times for different environmental conditions: control, cool wind, hot wind, and high relative humidity. We used hair dryers and a plastic bag to simulate the conditions. In Experiment 2, we picked bamboo (monocot), Macadamia integrifolia (dicot), Podocarpus (gymnosperm), and Polypodium (fern). We used dried nail polish to make impressions of the leaves of each plant species (abaxial and
adaxial) and observed each impression under a light microscope. We observed the number of stomates and their size and calculated the density. In Experiment 3, we used Platanus racemosa , which is a large leaf, and Phillyrea angustifolia , which is a small leaf. We measured the total length of the secondary veins for each leaf using a ruler and estimated the leaf area. We
You've reached the end of your free preview.
Want to read all 3 pages?
- Spring '18
- LAWREN SACK
- transpiration rate, stomata density, Platanus racemosa, Phillyrea angustifolia