Efectos del cadmio sobre la germinación y biomasa en variedades de caña de azúcar de la cuenca baja del Guayas
Fecha
2019
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Facultad de Ciencias Naturales. Universidad de Guayaquil
Resumen
Esta investigación tuvo como objetivo evaluar los efectos del cadmio sobre la germinación y
biomasa de cuatro variedades de caña de azúcar de la cuenca baja del Guayas, para proponer
una modificación del límite máximo permisible de cadmio en suelos cultivados con esta especie.
Se expusieron muestras de las variedades Ragnar, ECU-01, CC 85-92 y CC-22 al crecimiento
durante 21 días en un medio contaminado con cinco concentraciones de cadmio (0.5, 1, 2, 4 y
8 mg/L). El cadmio no presentó efectos sobre la germinación. Las radículas de las variedades
Ragnar, ECU-01 y CC-22 fueron significativamente afectadas en todos los tratamientos,
mientras que los hipocótilos presentaron afectación en los tratamientos de 2 y 8 mg/L en ECU-
01 y 2 mg/L en CC-22. La biomasa se vio afectada únicamente en la variedad ECU-01, donde
el tratamiento de 2 mg/L provocó una reducción del 51 % de esta. El índice integral de
fitotoxicidad reveló que este metal resultó tóxico en todos los tratamientos de las cuatro
variedades; por otro lado, el índice de tolerancia mostró que la variedad CC 85-92 fue la más
tolerante, mientras que ECU-01 resultó menos tolerante a los efectos del cadmio. Finalmente,
el índice de tolerancia y la biomasa de plántulas expuestas a experimentación con 0.25 mg/L,
demostraron que a esta concentración ninguna de las variedades de caña de azúcar presentó
afectaciones significativas, por lo que dicha concentración puede ser considerada como límite
máximo permisible en suelos cultivados con la especie Saccharum officinarum.
The aim of this research was to evaluate the effects of cadmium on the germination and biomass of four varieties of sugarcane from the lower basin of the Guayas river, in order to propose a modification in the maximum allowable limit of cadmium in soils cultivated with this specie. Samples of the varieties Ragnar, ECU-01, CC 85-92 and CC-22 were exposed to growth during 21 days in a contaminated environment with five concentrations of cadmium (0.5, 1, 2, 4 y 8 mg/L). Cadmium did not have effects on germination. Radicles of the Ragnar, ECU-01 and CC- 22 varieties were significantly affected in all the treatments, while the hypocotyls showed affectation in the treatments of 2 and 8 mg/L in ECU-01 and 2 mg/L in CC-22. The biomass was affected only in the ECU-01 variety, where the treatment of 2 mg/L caused a reduction of 51 % on it. The phytotoxicity integral index evidenced that the heavy metal was toxic in all the treatments of the four varieties; on the other hand, the tolerance index proved that CC 85-92 variety was the most tolerant, while ECU-01 was less tolerant to the effects of cadmium. Finally, the tolerance index and the biomass of seedlings exposed to experimentation with 0.25 mg/L, showed that to this concentration none of the varieties of sugarcane were affected significantly, so, that concentration can be considered as the maximum allowable limit in soils cultivated with the specie Saccharum officinarum.
The aim of this research was to evaluate the effects of cadmium on the germination and biomass of four varieties of sugarcane from the lower basin of the Guayas river, in order to propose a modification in the maximum allowable limit of cadmium in soils cultivated with this specie. Samples of the varieties Ragnar, ECU-01, CC 85-92 and CC-22 were exposed to growth during 21 days in a contaminated environment with five concentrations of cadmium (0.5, 1, 2, 4 y 8 mg/L). Cadmium did not have effects on germination. Radicles of the Ragnar, ECU-01 and CC- 22 varieties were significantly affected in all the treatments, while the hypocotyls showed affectation in the treatments of 2 and 8 mg/L in ECU-01 and 2 mg/L in CC-22. The biomass was affected only in the ECU-01 variety, where the treatment of 2 mg/L caused a reduction of 51 % on it. The phytotoxicity integral index evidenced that the heavy metal was toxic in all the treatments of the four varieties; on the other hand, the tolerance index proved that CC 85-92 variety was the most tolerant, while ECU-01 was less tolerant to the effects of cadmium. Finally, the tolerance index and the biomass of seedlings exposed to experimentation with 0.25 mg/L, showed that to this concentration none of the varieties of sugarcane were affected significantly, so, that concentration can be considered as the maximum allowable limit in soils cultivated with the specie Saccharum officinarum.
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Palabras clave
ÍNDICE DE TOLERANCIA, ÍNDICE INTEGRAL DE FITOTOXICIDAD, RADÍCULAS, HIPOCÓTILOS