Plants exhibit exceptionally intelligent behaviour when it comes to interactions with their environment. They can detect perceived threats, then convey warning signals to other plants via chemical signaling. Forewarned plants will then assemble their defenses against these potential threats, thus, increasing their chance of survival and reproduction. Communication and competition are common occurrences among the plant world. Another brilliantly, almost inconceivable capability plants possess is the ability to recognize coexisting family members within their home range. These intelligent life forms realize that if family members compete less with each other by allocation of their resources, their group will do better overall. This is a strategy utilized by many species, especially plants, to eliminate competition within their community in nature (Mancuso 2006).
Competition can occur between members of the same or different species. The involved individuals are negatively affected by other individuals that have the same living requirements, such as food or space. Inter-specific competition transpires when members of different species compete for a particular resource. Intra-specific competition arises when members of the same species compete with one another for a particular resource (Encyclopedia Britannica 2010). In this experiment we concentrate on inter-specific competition.
We measured the effect of competitor density on the growth of plants in order to observe the outcome of inter-specific competition. In set one (of two), our group utilized allelopathic rye grass (Secale cereal L.) as our competitor species. In set two, we made use of non-allelopathic oats (Avena fatua var. sativa) as our competitor species. The indicator species tested for both sets were red clover (Trifolium pretense).
Our group tested two species of plants that obtain their energy by different means of photosynthesis. One was a legume species that use C3 photosynthesis and are a nitrogen-fixing plant. The other was a non-legume species (ryegrass and oats), that use C3 photosynthesis to obtain energy. In a related study on inter-specific competition, researchers found that rust (a fungus that affects a variety of vegetation) is known to enhance perennial ryegrass (Lolium perenne L.) allelopathy against white clover (Trifolium repens L.). Interference from rusted ryegrass suppressed the yield of neighboring clover plants. This suggests that pathogen manipulated allelopathy, between plants and rust, amplified the ryegrass allelopathy against clover (Mattner 2001). The results suggested strong inter-specific competition between the ryegrass and the clover, as did ours.
Another study involving plant competition indicated that soil and leachate from rusted ryegrass were the reason for suppression of clover development. This experiment, along with the two previously discussed, provided strong evidence that inter-specific competition occurs between...