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

摘要

In order to evaluate the effect of cadmium (Cd~(2+)) 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 Cd~(2+) (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 Cd~(2+), for the in vitro and hydroponic experiment, respectively, the plantlets were separated into roots and shoot, which were analyzed for biomass as well as Cd~(2+), and macro (Ca~(2+), K~+ and Mg~(2+)) and micronutrient (Cu~(2+), Fe~(2+), Mn~(2+) and Zn~(2+)) contents. In the hydroponic experiment, there was no reduction in shoot and root dry weight for any Cd~(2+) level, regardless of the potato cultivar. In contrast, in the in vitro experiment, there was an increase in biomass at low Cd~(2+) levels, while higher Cd~(2+) levels caused a decrease. In general, Cd~(2+) 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 hydro_ponically grown plantlets were generally not affected by Cd~(2+). Our data suggest that the influence of Cd~(2+) on nutrient content in potato was related to the level of Cd~(2+) in the substrate, potato cultivar, plant organ, essential element, growth medium and exposure time.