The aim of the present study was to compare the effect of various salts composed of different cations (Na+, K+) and anions (chloride, nitrate, nitrite) on growth, development and ion accumulation in three Rumex species with accessions from sea coast habitats (Rumex hydrolapathum, Rumex longifolius and Rumex maritimus) and Rumex confertus from an inland habitat. Plants were cultivated in soil in an experimental automated greenhouse during the autumn–winter season. Nitrite salts strongly inhibited growth of all Rumex species, but R. maritimus was the least sensitive. Negative effects of chloride salts were rather little-pronounced, but nitrates resulted in significant growth stimulation, plant growth and development. Effects of Na+ and K+ at the morphological level were relatively similar, but treatment with K+ salts resulted in both higher tissue electrolyte levels and proportion of senescent leaves, especially for chloride salts. Increases in tissue water content in leaves were associated with anion type, and were most pronounced in nitrate-treated plants, resulting in dilution of electrolyte concentration. At the morphological level, salinity responses of R. confertus and R. hydrolapathum were similar, but at the developmental and physiological level, R. hydrolapathum and R. maritimus showed more similar salinity effects. In conclusion, the salinity tolerance of all coastal Rumex species was high, but the inland species R. confertus was the least tolerant to salinity. Similarity in effects between Na+ and K+ could be related to the fact that surplus Na+ and K+ has similar fate (including mechanisms of uptake, translocation and compartmentation) in relatively salt-tolerant species. However, differences between various anions are most likely related to differences in physiological functions and metabolic fate of particular ions.

The aim of the present study was to evaluate tolerance to salinity and different heavy metals as well as the phytoextraction potential of Ranunculus sceleratus plants from a brackish coastal sandy beach habitat. Four separate experiments were performed with R. sceleratus plants in controlled conditions: (1) the effect of NaCl gradient on growth and ion accumulation, (2) the effect of different Na+ and K+ salts on growth and ion accumulation, (3) heavy metal tolerance and metal accumulation potential, (4) the effect of different forms of Pb salts (nitrate and acetate) on plant growth and Pb accumulation. A negative effect of NaCl on plant biomass was evident at 0.5 g L−1 Na+ and growth was inhibited by 44% at 10 g L−1 Na+, and this was associated with changes in biomass allocation. The maximum Na+ accumulation (90.8 g kg−1) was found in the stems of plants treated with 10 g kg−1 Na+. The type of anion determined the salinity tolerance of R. sceleratus plants, as Na+ and K+ salts with an identical anion component had a comparable effect on plant growth: nitrates strongly stimulated plant growth, and chloride treatment resulted in slight but significant growth reduction, but plants treated with nitrites and carbonates died within 4 and 5 weeks after the full treatment, respectively. The shoot growth of R. sceleratus plants was relatively insensitive to treatment with Mn, Cd and Zn in the form of sulphate salts, but Pb nitrate increased it. Hyperaccumulation threshold concentration values in the leaves of R. sceleratus were reached for Cd, Pb and Zn. R. sceleratus can be characterized as a shoot accumulator of heavy metals and a hyperaccumulator of Na+. A relatively short life cycle together with a high biomass accumulation rate makes R. sceleratus useful for dynamic constructed wetland systems aiming for the purification of concentrated wastewaters.

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Minimization of the possible harmful effects of soil pollution on agricultural production and food safety are the major challenges in modern agriculture. There is great scientific interest in the detailed understanding of the physiology of lead uptake and toxicity in Zea mays, together with the search for approaches to minimizing Pb accumulation in tissues. The aim of the present study was to explore the possibility of reducing Pb accumulation in Z. mays plants cultivated in Pb-contaminated soil, by means of vermicompost amendment. Z. mays plants were cultivated at three soil vermicompost amendment rates (10, 20, and 30%), with the addition of 1000 mg L−1 of Pb in the form of Pb(NO3)2 or an equivalent amount of nitrogen in the form of NH4NO3. Additional nitrogen had a significant stimulatory effect on plant growth and physiology, but only for control plants, and at a low vermicompost amendment rate. Independently, Pb had an insignificant negative effect on plant growth and biomass partitioning, but significantly negatively affected the mineral nutrition of Z. mays plants. At a 10 and 20% soil vermicompost amendment rate, the Pb concentration in plant leaves and roots decreased by 65%, while plant biomass increased four to five times in comparison to soil-grown control plants, together with accelerated flowering. It was concluded that vermicompost is one of the most promising soil amendments for reducing heavy metal uptake and accumulation in crop plants, while also being an efficient organic fertilizer.