Lead- and Mercury-Uptake and Genetic Damage Detection in Pechay (Brassica rapa ssp. Pekinensis) Roots

Abstract

Brassica rapa ssp. pekinensis seedlings were exposed to heavy metal (lead and mercury) stress to determine the effect of heavy metal uptake on root elongation and to detect if heavy metal uptake induces genetic damage in root cells. The heavy metal concentrations which resulted in 50% reduction of seed germination (750 ppm for lead and 500 ppm for mercury) were used as basis for the sowing concentrations (500, 750, and 1000 ppm for lead and 250, 500, and 750 ppm for mercury). Five-day old seedlings were observed for root elongation and tissues were assessed for genetic damage. Greater concentrations of either lead or mercury resulted in lower percentage germination and seedlings with shorter roots. Compared to lead, mercury is noted to exert more toxic effects on seedling germination and root elongation. No genetic damage was detected, even with increased amounts of heavy metals.