Cadmium and mineral nutrient accumulation in potato plantlets grown under cadmium stress in two different experimental culture conditions

In order to evaluate the effect of cadmium (Cd2+) toxicity on mineral nutrient accumulation in potato (Solanum tuberosum L.), two cultivars named Asterix and Macaca were cultivated both in vitro and in hydroponic experiments under increasing levels of Cd2+ (0, 100, 200, 300, 400 and 500 μM in vitro and 0, 50, 100, 150 and 200 μM in hydroponic culture). At 22 and 7 days of exposure to Cd2+, for the in vitro and hydroponic experiment, respectively, the plantlets were separated into roots and shoot, which were analyzed for biomass as well as Cd2+, and macro (Ca2+, K+ and Mg2+) and micronutrient (Cu2+, Fe2+, Mn2+ and Zn2+) contents. In the hydroponic experiment, there was no reduction in shoot and root dry weight for any Cd2+ level, regardless of the potato cultivar. In contrast, in the in vitro experiment, there was an increase in biomass at low Cd2+ levels, while higher Cd2+ levels caused a decrease. In general, Cd2+ decreased the macronutrient and micronutrient contents in the in vitro cultured plantlets in both roots and shoot of cultivars. In contrast, the macronutrient and micronutrient contents in the hydroponically grown plantlets were generally not affected by Cd2+. Our data suggest that the influence of Cd2+ on nutrient content in potato was related to the level of Cd2+ in the substrate, potato cultivar, plant organ, essential element, growth medium and exposure time.