Determinación de las concentraciones elementales mediante ICP-MS

Whilst investigating the mechanism of exotic plant invasion, discrepancies relating to the phytotoxicity of allelochemicals arise. Failure in the reproduction of the results published in one species elsewhere in the world occurs. It must be recalled that the time and place of the soil sampling, the duration between various soil sampling, experimentation and storage conditions of the soil during the transit from the site of collection to the laboratory, techniques used for the bioassay, and environmental conditions all contribute to a completely different set of results (Inderjit et al.2006). The studies performed have to be repeatable, and stringent working conditions need to be established to avoid contradictory theories on the invasion of the same exotic species. Several mechanisms of invasion, soil biota feedbacks have been presented in the past. However only in a very few invasive species have the direct and indirect mechanisms been explained. Lack of identifi- cation of key microbial ingredient exists with most successful invasions. Assimila- tion of a microbial profile of the invasive plant in question both in the invaded and the home range would contribute towards designing templates for formulating bioherbicides. More reliable conclusions regarding invasive plants especially those altering the underground microbial communities need to be made for a better understanding for which an explicit approach of plant-soil biota feedback experi- ments need to be performed. With the soil microbiota in question, the rates of degradation of the allelochemical, the population density of the microbe, and the rates of microbial degradation all come in to the study and have to be evaluated for a more realistic conclusion. Besides the extension and supporting theories of the NWH, the concept of EICA needs to be addressed in plant invasion ecology (Callaway and Ridenour2004). The plant nutrient trade-offs for defense and growth in the new environment would allow us to understand the need for a plant to choose either one in the newly invaded range. Successful failure of some of the invasions with significance in agro-forestry (Scheffer 2003) will also improve our under- standing of the belowground flora and fauna which might mitigate our lack of knowledge in invasions.

Acknowledgements H.P.B. acknowledges the support from University of Delaware and Univer- sity of Delaware Research Foundation (UDRF).

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Volatile Interaction Between Undamaged Plants: