Ecology Lab Report
Sampling Stomatal Densities of Various Species of Plants
The importance of stomata is the fact that they control the intake of carbon dioxide and the loss of water in plants. The ratio of intake to loss creates a better picture of which plants adapt would to their environment and which would not. Eight different plant species were sampled the stomatal densities and compared them to their environments. The densities were recorded for each species by painting clear nail polish on the adaxial side of leaf. Clear tape was laid over the nail polish then removed and placed on a microscope slide and placed under a compound microscope. Three sections of each leaf were observed with the highest recorded. The number of stomata obtained was then concerted to stomata per mm2. The hypothesis predicted that hydrophytes would have the highest stomatal density followed by mesophytes with a medium amount and xerophytes with the least. It was shown that Kalinchoe delagoensis, xerophyte, Rhoeo spathacea, mesophyte, and Zebrina sp, hydrophyte. had the lowest stomatal densities. Cyperus papyrus, hydrophyte, and Hibiscus sp. mesophyte, had the highest stomatal densities. Bouganville and Monstera deliciosa both fell in the middle of the spectrum; while Fiscus sp. also had a high stomatal density.
The ecological field is growing everyday with one area of study in particular; stomatal density. This field of study is important because it shows how and when plants are more susceptible to environmental changes and how quickly they will adapt themselves. Stomata control gas exchange in the leaves of vascular plants. Open stomata allow carbon dioxide to enter the leaves and water and oxygen to leave. Stomata are located on the underside of the leaf to decrease descication. If the environment that the plant lives in is too sunny, cytochromes, membranes and pigments can ‘bake under the sun’. As a coping mechanism, the stomata open and release water to lower their temperature; similar to the way humans sweat. When water is scarce, evaporation such as explained above can lead to desiccation of the plant. Xerophytes are plants that are able to survive in areas with very little moisture. Mesophytes are plants that are neither adapted to a dry nor wet environment. Hydrophytes are plants that have adapted to live in a very moist or aquatic environment (Campbell et al. 2008). In the following experiment there will be comparisons drawn upon these different types of plants.
In a study on Spartina (Maricle et al. 2009), thirteen species were studied of Spartina ranging high to low marsh and freshwater habitats. The scientists studying Spartina grasses used light and electron microscopes to measure and record the number of stomata on the adaxial side of the leaf. Thirteen species were collected and examined: Spartina alterniflora, Spartina anglica, Spartina argentineses, Spartina bakeri, Spartina densiflora, Spartina patens, Spartina spartinae, Spartina cynosuriodes, Spartina pectinata, and Spartina gracilis. The species were compared against herbarium specimens and Flora from the North American Keys; but the populations used in the study were grown under greenhouse conditions in Fort Hays State University and Washington State University. The scientists studying Spartina grasses used light and electron microscopes to measure and record the number of stomata on the abaxial and adaxial side of the leaf. Results showed that in freshwater species, there were more stomata on both sides; conversely, in saltwater species, there were more stomata on the adaxial side. Saltwater species were able to better adapt to their climate and water loss due to the number of stomata present (Maricle et al. 2009). Konrad and colleagues (2009) report that stomata changes are shown to be inversely proportional to atmospheric CO2 concentration. The article stated that fossils were used to introduce...
Citations: Cain, M. L., W. D. Bowman, and S. D. Hacker. 2011. Ecology. Sinauer Associates, Sunderland, Massachusetts, USA.
Campbell, Neil A., Reece, Jane B., Urry, Lisa A., Cain, Micheal L., Wasserman, Steven A., Minorsky, Peter V., Jackson, Robert B. Biology. San Francisco: Benjamin Cummings, 2008.
Konrad, W., A. Roth-Nebelsick, and A. Grein. 2007. Modelling of stomatal density response to atmospheric CO2. Journal of Theoretical Biology 253: 638-658.
Maricle, B. R., N. K. Koteyeva, E. V. Voznesenskaya, J. R. Thomasson, and G. E. Edwards. 2009. Diversity in leaf anatomy, and stomatal distribution and conductance, between salt marsh and freshwater species in the C4 genus Spartina (Poaceae). New Phytologist 184: 216-233
The Taxonomicon. N.p., 2011. Web. 9 Mar. 2012.
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