Resumen

RIVERA-CRUZ, María del Carmen  y  TRUJILLO-NARCIA, Antonio. Estudio de toxicidad vegetal en suelos con petróleos nuevo e intemperizado. INCI [online]. 2004, vol.29, n.7, pp.369-376. ISSN 0378-1844.

The study of plant behavior in petroleum contaminated soils allows the identification and selection of oil pollution indicator species. The effect of soil petroleum on the diversity, canopy and productivity of a prairie in Southeastern Mexico was studied. Different and tempered petroleum concentrations were evaluated on the germination, growth, aerial, root and total biomasses, and number of nodules. The praire was divided in four areas according to the total petroleum hydrocarbons (THP) concentration: 150, 2791, 9035 and 79457mg·kg^-1. The largest diversity was found in the two most contaminated soils but biomass production was 50% lower than in the soil with less THP. Three sequential experiments were carried out, on sprouts for a 32 day exposure to oil, and on plants for a 150 day exposure, using a random factorial analysis and the species Echinochloa polystachya, Brachiaria mutica, Cyperus articulatus, Cyperus sp. and Mimosa pigra. Three concentrations (50000, 100000 y 150000 mg·kg^-1) were prepared for comparison with tempered petroleum (79457mg·kg^-1). OECD Protocol Nº208 was applied to evaluate the toxic effects on sprouts and a protocol was designed for plants. Germination, height, root length, biomass and number of nodules were evaluated. Significant differences were found in all variables in sprouts and plants of the five species. Germination was positively associated with the largest tempered petroleum concentrations but growth, root length, biomass and number of nodules were reduced in sprouts. In plants all the variables were reduced. The most sensitive species, best phytoindicators of toxic levels were E. polystachya and B. mutica in sprouts and M. pigra in plants

Palabras clave : Brachiaria; Cyperus ; Echinochloa; Fitotoxicidad; Hidrocarburos; Mimosa.