The aim of experiments was to assess the efficiency of choline-stabilized orthosilicic acid (ch-OSA; complex of orthosilicic acid with choline and a bioavailable source of silicon) application under increasing manganese (Mn) stress on the micronutritional composition and yielding of tomato (Solanum lycopersicum L. cvs. 'Alboney F1' and 'Emotion F1'). Plants were grown in rockwool with the application of a nutrient solution varied the Mn concentrations (in mg dm(-3)): 9.6 and 19.2 which cause strong oxidative stress of plants comparing with optimal concentration of that microelement in nutrient solution. The effect of ch-OSA application (at Si concentration of 0.3 mg dm(-3) nutrient solution) was investigated at both Mn-levels. Increasing Mn stress modified the concentration of microelements and silicon (Si) in tomato leaves. Application of ch-OSA also influenced the concentration of nutrients, but the determined changes were generally multidirectional and varied depending on Mn-level and cultivar. Under the increasing Mn stress a significant downward trend was observed for the mean concentration of Fe (in both cultivars) in fruits--but changes of Mn, Zn and Cu were varied depend on cultivar. In the case of cv. 'Alboney F1' ch-OSA application caused an increase the mean concentrations of Fe, Zn and Cu, while in the case of cv. 'Emotion F1' the reduction of mean concentrations of Zn and Cu was recorded. Ch-OSA treatment did not influence on the Mn concentrations in fruits. A beneficial role of ch-OSA was also found in photosynthesis activity. This was especially valid for lower levels of Mn. Application of ch-OSA improved significantly the marketable yield of tomato under stress by a low Mn level.

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Key message Zn caused an increase of photosynthesis activity, carbohydrates and chlorophyll at the level 1-2.5 mM, while phenols revealed a continuous increase together with Zn increase in the medium. Abstract The aim of the present study was to determine the effect of various Zn application levels on some physiological, morphological and biochemical parameters of a hybrid Salix purpurea 9 triandra 9 viminalis 2. Plants were cultivated under control conditions with application of Zn in the range 0-5 mM. The effects on net photosynthesis rate (P N ), stomatal conductance (g s ), transpiration rate (E), intercellular CO 2 (C i ), chlorophyll a and b, carotenoids, growth, sugars and phenols were analysed. Our investigations confirmed a dual role of Zn, with benefits at the level 1-2.5 mM, and a decrease of measured photosynthesis activity, carbohydrates and chlorophyll below and above this range. Moreover, the decrease of these parameters at the highest Zn application did not reach the level of control plants. This means that this species may have further potential as an accumulator in polluted areas. However, phenols revealed a continuous increase together with Zn increase in the medium.

Rare earth elements (REEs) are a group of elements whose concentration in numerous environmental matrices continues to increase; therefore, the use of biological methods for their removal from soil would seem to be a safe and reasonable approach. The aim of this study was to estimate the phytoextraction efficiency and distribution of light and heavy (LREEs and HREEs) rare earth elements by three herbaceous plant species: Artemisia vulgaris L., Taraxacum officinale F.H. Wigg. and Trifolium repens L., growing at a distance of 1, 10, and 25 m from the edge of a frequented road in Poland. The concentration of REEs in soil and plants was highly correlated (r > 0.9300), which indicates the high potential of the studied plant species to phytoextraction of these elements. The largest proportion of REEs was from the group of LREEs, whereas HREEs comprised only an inconsiderable portion of the REEs group. The dominant elements in the group of LREEs were Nd and Ce, while Er was dominant in the HREEs group. Differences in the amounts of these elements influenced the total concentration of LREEs, HREEs, and finally REEs and their quantities which decreased with distance from the road. According to the Friedman rank sum test, significant differences in REEs concentration, mainly between A. vulgaris L., and T. repens L. were observed for plants growing at all three distances from the road. The same relation between A. vulgaris L. and T. officinale was observed. The efficiency of LREEs and REEs phytoextraction in the whole biomass of plants growing at all distances from the road was A. vulgaris L. > T. officinale L. > T. repens L. For HREEs, the same relationship was recorded only for plants growing at the distance 1 m from the road. Bioconcentration factor (BCF) values for LREEs and HREEs were respectively higher and lower than 1 for all studied plant species regardless of the distance from the road. The studied herbaceous plant species were able to effectively phytoextract LREEs only (BCF > 1); therefore, these plants, which are commonly present near roads, could be a useful tool for removing this group of REEs from contaminated soil.

The aim of study was to determine the phytoextraction of rare earth elements (REEs) to roots, stems and leaves of five herbaceous plant species (Achillea millefolium L., Artemisia vulgaris L., Papaver rhoeas L., Taraxacum officinale and Tripleurospermum inodorum), growing in four areas located in close proximity to a road with varied traffic intensity. Additionally, the relationship between road traffic intensity, REE concentration in soil and the content of these elements in plant organs was estimated. A. vulgaris and P. rhoeas were able to effectively transport REEs in their leaves, independently of area collection. The highest content of REEs was observed in P. rhoeas leaves and T. inodorum roots. Generally, HREEs were accumulated in P. rhoeas roots and leaves and also in the stems of T. inodorum and T. officinale, whereas LREEs were accumulated in T. inodorum roots and T. officinale stems. It is worth underlining that there was a clear relationship between road traffic intensity and REE, HREE and LREE concentration in soil. No positive correlation was found between the concentration of these elements in soil and their content in plants, with the exception of T. officinale. An effective transport of REEs from the root system to leaves was observed, what points to the possible ability of some of the tested plant species to remove REEs from soils near roads.Electronic supplementary materialThe online version of this article (doi:10.1007/s11356-017-8944-2) contains supplementary material, which is available to authorized users.

Nutrition is one of the most important factors influencing quantitative and qualitative plant yield. This study examined the effect of manganese (Mn) in nutrient solution on photosynthetic activity parameters, and the relations between photosynthetic activity parameters, yield and plant nutrient status in tomato (Solanum lycopersicum L.). Mn supplementation significantly modified the nutrient content of leaves. Macronutrient content varied less than micronutrient content. The optimal Mn concentration differed between the studied cultivars. Both Mn deficit and Mn excess caused a decrease of tomato yield. Gas exchange parameters, relative water content (RWC) and specific leaf area (SLA) were measured in fully expanded tomato leaves. Certain levels of Mn were found to be needed for proper plant function and future yield, and toxic effects of excess Mn were noted. Changes in P N (net photosynthetic rate) were found to be the first signal of plant response to higher Mn supply, while yield was as for optimal Mn concentrations. Under Mn treatment, uptake of some nutrients increased. A higher level of absorbed Mg led to a higher photosynthesis rate and increased stomatal opening. P N and g s (stomatal conductance) also increased, while C i (intercellular CO 2 concentration) decreased, indicating proper CO 2 consumption during the assimilation process.K Ke ey y w wo or rd ds s: : Macroelement, microelement, Solanum lycopersicum L., photosynthetic activity, manganese stress.

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We measured cadmium and lead concentrations in two littoral plants (Phragmites australis Cav. Trin ex. Steudel and Typha angustifolia L.) collected in June and September 2007 from five selected lakes in the Poznan city area, and also in sediment and water samples from the same places. We determined the metal concentrations in rhizomes and leaves, and in sediment and water from the littoral and near the bank zone. Only low levels of the heavy metals were found. Pb and Cd concentrations were higher in water collected from the bank zone than from the littoral zone. Pb and Cd accumulation was noted in sediments. Heavy metal levels were higher in rhizomes than in stems and leaves. The studied aquatic macrophytes may be bioaccumulators and bioindicators of Pb and Cd in freshwater in natural conditions, even when concentrations are low.K Ke ey y w wo or rd ds s: : Cadmium, lead, accumulation, Phragmites australis, Typha angustifolia.ACTA BIOLOGICA CRACOVIENSIA Series Botanica 52