Introduction to Biology Lab- Pre-lab for Ecology Lab #8
A.) Hierro, Jose L., and Ragan M. Callaway. "Allelopathy and Exotic Plant Invasion." Plant and Soil 256.1 (2003): 29-39. Springer.com. Kluwer Academic Publishers, 13 May 2003. Web. 7 Mar. 2013. <http://download.springer.com/static/pdf/801/art%253A10.1023%252FA%253A1026208327014.pdf?auth66=1363980296_005e124552dacf48bf5fb9abb2861861&ext=.pdf>. B.) This article documented an experiment done on an invasive forb found in the foothills of the Caucasus Mountains in the Republic of Georgia known as Centaurea diffusa and its allelopathic effects on three native species of bunchgrass, Festuca ovina, Koleria laerssenii, and Agropyron cristatum, as well as its effect on 3 foreign, North American bunchgrass species, F. idahoensis, K. cristata, and Pseudorogeneria spicata. C. diffusa had little to no competitive effect on the native Eurasian bunchgrass species, as the uptake of the phosphorous isotope 32P was not decreased and the biomass of the plants was not reduced. On the other hand, the C. diffusa had a significant competitive effect on the North American bunchgrass species and greatly reduced their biomass and inhibited the uptake of 32P. The presence of the North American bunchgrass species had no effect on the biomass or 32P production by C. diffusa. Evidence for interspecific competition was present between C. diffusa and the Eurasian bunchgrass species K. laernssenii, as C. diffusa had no effect on the biomass or 32P uptake of the K. laerssenii, but the K. laerssenii did reduce the uptake of 32P and decreased the biomass of the C. diffusa. C. diffusa and K. laerssenii engage in “chemical warfare” through the method of allelopathy known as exudation. They both release phytotoxic chemicals into the soil via their roots. C. diffusa produces caryophyllene oxide and linoleic acid, which when mixed with other inactive chemicals produced by the plant create a phytotoxin that is released into the...
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