Heavy Metal Allocation to Pea Plant Organs (Pisum sativum L.) from Soil during Different Development Stages and Years

Abstract

The incorporation of heavy metals contained in soils into the food chain is mediated by plants. Plants show varying abilities to take up and accumulate these elements during vegetative growth. In this study, changes in the content, rate of uptake, accumulation, and translocation of heavy metals during six stages of development of pea plants were determined. In field experiments, two pea cultivars were cultivated in two consecutive growing seasons. The harvested plants were divided into the roots and aerial parts, and at full maturity the seeds were separated additionally. Significant changes in the content of the heavy metals in the separated parts and on average in the entire plant, as well as their bioaccumulation factors (BAFs), were most often noted up to the flowering stage of pea plants, after which these values usually did not change significantly. The highest rate of uptake of heavy metals per day of growth was noted between the full flowering stage and the stage when 50% of pods were of typical length. Their translocation factor (TF) was most often highest between the three-internode stage and the full flowering stage. The content, uptake, BAF, and TF of the heavy metals most often varied between years of the study, but did not significantly depend on the pea cultivar. The BAF indicates the potential of pea plants to hyperaccumulate lead and zinc and moderate accumulation of other heavy metals in their aerial parts. Excessive concentrations of lead and cadmium disqualified pea’s seeds to be used as human food, whereas excessive concentrations of lead prevented their use as fodder. Green mass of pea plants can be used as animal fodder according to the EU directives.