EEB 162L Week 6 - Title Affects of Air Temperature and Light on Transpiration Rate and Differences in Stomata Size and Leaf Venation Trends with Leaf

EEB 162L Week 6 - Title Affects of Air Temperature and...

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Title: Affects of Air Temperature and Light on Transpiration Rate and Differences in Stomata Size and Leaf Venation Trends with Leaf Size and Drought Tolerance Introduction: Water conservation is incredibly important for plants. Within only a few hours, a plant leaf would normally dry out if it were not for features such as the cuticle and stomates that close (Sack 2016). In one experiment, we test how different variables such as air temperature and light affect the transpiration rate of plant leaves. Understanding rates of transpiration provides us with information on how plants are adapted to their different ecologies. It can provide us with information on how temperature and other climate conditions affect a plant’s ability to absorb and maintain ideal water levels (Wullschleger 2000). We hypothesized that blowing hot air on the leaves would yield the highest transpiration rates. We predict this based on trends of boundary layers. Stomata are also important in transpiration. They are the openings on leaves that control the rate of carbon dioxide intake for photosynthesis. However, when they are open, they also cause water to be lost to air in plants. Due to this trade off of photosynthesis, it is important to understand the differences in stomata size and stomatal density among different leaves of species of different habitats. Comparing these differences illustrates the need for various plant adaptations for survival in different ecologies (Mitton 1998). In a second experiment, we measured stomata distribution, frequency, and size in one monocot, dicot, gymnosperm, and fern species. We hypothesized that stomatal density would be highest in dicots but stomatal size would be smallest. We predict this based on monocots being amphistomatic and dicots being hypostomatic (Mitton 1998). Stomata would have to be denser if they are distributed only on the underside of a leaf compared to both sides. To be more dense, stomata have to be smaller in order to fit more in a given area. In a third experiment, we examined leaf venation in small and large leaves from dry and moist habitat species. Leaf venation is important for transporting water throughout the leaf to make up for the water lost due to carbon dioxide capture (Sack 2016). We hypothesized that large leaves from dry habitat species would have the greatest major vein lengths per area. We predict this since a dry habitat would cause the plant to dry out more easily, so it needs larger major vein area to supply water to the leaf. A larger leaf would dry out more easily, so it would also drive the need for more major vein area.
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  • Spring '18
  • LAWREN SACK
  • transpiration rate, adaxial stomata, stomata length

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