Resumen

PERNIA, Beatriz et al. Effects of cadmium on the germination and initial growth of five varieties of Oryza sativa cultivated in Ecuador. Acta Agron. [online]. 2021, vol.70, n.1, pp.82-92.  Epub 17-Nov-2021. ISSN 0120-2812.  https://doi.org/10.15446/acag.v70n1.87636.

Cadmium is a heavy toxic metal that affects the growth and productivity of plants. In Ecuador, it has been demonstrated that there is contaminated by this metal in agricultural soils. The objective of the present research was to evaluate the effects of cadmium on the germination and initial growth of five varieties of Oryza sativa L. cultivated in Ecuador, with the final purpose of identifying the general tolerance to Cd of the different cultivars. The varieties of seeds of ‘INIAP-11’, ‘INIAP-14’, ‘INIAP-FL-Arenillas’, ‘INIAP-FL-Cristalino’, and ‘SFL-011’ were exposed to different concentrations of cadmium (0, 0.25, 0.5, 1, 2, 4 y 8 mg L-1 Cd) during eight days, through which it was determined the mortality percentage, the germination percentage (PG), the time and average speed germination (TMG-VMG), and the length of the radicle and hypocotyl. The effect of the metal was evaluated by calculating the tolerance index (TI), the integral phytotoxicity index (IIF), and the mean inhibitory concentration (CI50). The Cd didn't affect the PG, TMG, nor the VMG. There was an inversely proportional correlation between the cadmium concentration and the length of the radicles (P < 0.05). The most tolerant variety was the ‘SFL-011’ with an IC50 of 4.02 mg L and it was observed initial growth stimulation at low concentrations of Cd, reflected in a negative IIF and in an IT superior to 1. The variety ‘SFL-011’ was the most tolerant one to Cd, followed by ‘INIAP-FL Arenillas’. The length of the radicles is a parameter that could be used as a bio-indicator of the contamination of cadmium on rice varieties.

Palabras clave : integral phytotoxicity index; ‘INIAP-FL-Arenillas’; heavy metals; ‘SFL-011’; tolerance.

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