length of the secondary veins for each leaf using a ruler and estimated the leaf area. We calculated secondary vein length per area. The detailed steps of each experiment can be found in the lab manual. Results The results from Experiment 1 as shown in the attached table showed that hot wind led to a significant increase in transpiration rate while cold wind led to a slight decrease in transpiration rate. Higher relative humidity, on the other hand, led to a significant decrease in transpiration rate. The results from Experiment 2 as shown in the attached table showed that Macadamia integrifolia had the highest abaxial stomata density with a relatively large stomata size. On the other hand, Polypodium (fern) had the lowest abaxial stomata density along with the largest stomata size. None of the plant species had an adaxial stomata density. The results from Experiment 3 as shown in the attached table showed that Platanus racemosa had the larger leaf size, but with significantly smaller secondary vein length density compared to Phillyrea angustifolia . Discussion The results of Experiment 1 supported my hypotheses. The environmental condition with hot air led to a significant increase in transpiration rate compared to the control condition, while the higher relative humidity condition led to a significant decrease. The condition with cold air led to only a slight increase in transpiration rate. This implied that an environment with high wind can lead to an increase in boundary layer; and with the addition of higher temperature, the leaf boundary layer became thinner than normal, leading to an increase in transpiration rate. The same occurred in the cold wind condition, however its temperature prevented significant increase. A higher relative humidity led to a decrease in transpiration rate because there is less driving source for water diffusing out of the stomata (Yocum, 1935). The results of Experiment 2 supported my hypothesis. While none of the plant species had any adaxial stomata density, Macadamia integrifolia (dicot) had the highest abaxial stomata density. While
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- Spring '18
- LAWREN SACK
- transpiration rate, stomata density, Platanus racemosa, Phillyrea angustifolia