A b s t r a c tThe main aim of the present study was to evaluate the influence of the chemical composition of a nutrient solution (NS I, NS II), seed inoculation with Effective Microorganisms (EM), and assimilation illumination (AI) of plants on the growth, development and nutritional status of lettuce (Lactuca sativa L.) in hydroponic cultivation and microbiological changes in the medium. The measurements were as follows: quantity of leaves per plant (LQ), surface area of the biggest leaves of plants (SBL), relative chlorophyll content (SPAD units), total fresh weight (TFW), total dry weight (TDW), percentage (%) of dry matter (% DM), chemical composition of leaves, nutrient uptake (N, P, K, Ca, Mg, Na) of the aboveground parts of the plant. It was shown that the simultaneous inoculation of seeds with EM and application of NS II had an effect on improving seed germination (1 st -5 th day after sowing), but a significantly positive influence of NS I on seed germination was found from the 5 th to 9 th day. The application of NS II and EM-A had a positive influence on the development of leaves on the plant. The chemical composition of the nutrient solution was found to have a significant effect on the biometrical parameters of plants. The use of supplemental lighting in cultivation of lettuce affected positively both the growth and development of plants. The chemical composition of the nutrient solution significantly modified the macronutrient nutrition status of plants, while the illumination of plants only in case of phosphorus -but at the same time it had a significant influence on the uptake of all nutrients by the plant. The influence of EM was not proved. The microbiological analysis showed a significant influence of the chemical composition of nutrient solutions on the changes in the numbers of the analyzed groups of microorganisms, showing an increase in their numbers in nutrient solutions with higher contents of chemical elements. However, there were no significant changes in the number of microorganisms relative to the treatment with assimilation illumination and to that of seed inoculation with EM solutions.

Copper, zinc, iron and manganese contents were determined in edible parts of some fresh vegetables sold on markets in Poznañ. The copper and zinc contents in vegetables obtained in the present study were compared to the ones reported from an analogous study carried out in the Department of Horticultural Plant Fertilization in Poznañ fifteen years ago. Samples of vegetables were collected from six points distributed in the area of Poznañ from March to July at monthly intervals. For the study, vegetables were divided into three groups according to edible parts: leaves (lettuce, cabbage, parsley, leek), roots (carrot, celeriac, parsley) and fruits (tomato, cucumber). The concentration of copper, zinc, iron and manganese was determined by the atomic flame absorption method using an AAS 3 Zeiss apparatus. The highest content of copper was found in roots of celeriac, while the smallest content was shown in cabbage leaves. The highest mean content of zinc was found in lettuce leaves and the lowest one in tomato fruit. The mean content of copper in all the vegetable species was lower in 2005 than in 1993. In 1993 more zinc was found in vegetables whose edible parts were fruits compared to the results of 2005. The vegetables whose leaves and roots are eaten were characterized by a higher zinc content in 2005. The highest content of iron was found in leaves of leek, while the lowest amounts were determined in tomato and cucumber fruits. The highest mean content of manganese was found in leaves of lettuce, while the smallest amount was in carrot roots. The iron content in the vegetables whose leaves and fruits are edible parts was lower in 2005 than in 1993, while the root vegetables were characterized by more iron in 2005. Higher content of manganese in all the vegetable species examined was found in 1993 than in 2005.

Two seedling rootstocks of Mahaleb cherry (Prunus mahaleb L.) from a German type cv. Alpruna marked as No. 2 and No. 6 were selected for their semi-dwarfing properties from biotypes growing at the Rural Experimental Station in Baranowo belonging to the University of Life Sciences in Poznan, Poland. In an orchard experiment in 2012-2013, growth and yield of eight-and nine-year old trees of the cvs Regina, Summit and Vanda were studied. These cultivars were grafted on Mahaleb cherry No. 2 and No. 6 and were compared to the control rootstock Mazzard (Prunus avium L.) cv. Alkavo. The Mahaleb cherry biotypes significantly decreased the trunk cross-sectional area and the crown volume of the trees. The cultivars grafted on Mahaleb cherry biotypes No. 2 and No. 6 had more flowers and they gave a higher yield. The yield efficiency for cultivars grafted on these rootstocks was higher than for rootstock Mazzard. Significant differences of the concentration of the elements were found for Fe, Cu, Zn in fruit and for Fe, Cu and Cr in leaves. Presence of Pb and Cr was not detected in sweet cherry fruit.

Cultivation of sweet cherry trees is growing in popularity in Poland thus there is an increasing demand for good quality nursery material. The growth of maiden sweet cherry trees of ‘Vanda’ depending on three rootstocks was compared within three years of the nursery experiment. Also the nutritional status as well as photosynthetic activity of maiden trees after the use of four foliar preparations were in the scope of interest. On the basis of the size of the trunk diameter and weight of maiden sweet cherry tree fresh mass as well as on the basis of dry mass of leaves, the strongest vigor of growth was observed on Colt rootstock, contrary to the vigor on GiSeLa 5 rootstock, in which it was the weakest. Maidens produced on Colt rootstock formed more lateral shoots in comparison to other rootstocks. After foliar fertilization, maiden sweet cherry trees growing on Colt rootstock did not show better parameters of growth, except for Maxi Grow Excel preparation that caused better results of growth. The influence of preparations used on the content of macro and microelements was differentiated. A positive effect of all preparations was noted as far as gas exchange parameters were concerned, especially in the case of Maxi Grow Excel.

Abstract:In the pot experiment the effect of increasing doses of Ni (the control, 25, 50, 75, 150, 300 mg · dm -3 substrate) on the content of this metal in individual organs of aboveground parts was investigated in three selected species of ornamental plants: Aztec marigold (Tagetes erecta L.), sunflower (Helianthus annus L.) and love-lies-bleeding (Amaranthus caudatus L.). A significant effect of increasing Ni doses on the content of this metal was found in individual organs of selected species. In Tagetes erecta L. and Amaranthus caudatus L. the highest amounts of nickel were accumulated in leaves, while in sunflower growing in the substrate, to which nickel was introduced at 25, 50, 75 and 150 mg·dm -3 , the highest amounts of this metal were accumulated in inflorescences. Among the analyzed species of ornamental plants growing in the substrate with no addition of this metal and in the substrate with an addition of 25 and 50 mg Ni · dm -3 the highest nickel uptake was observed in Tagetes erecta L. plants. For the substrate with an addition of 75, 150 and 300 mg Ni · dm -3 the biggest nickel accumulation was recorded in Amaranthus caudatus L.Keywords: nickel, ornamental plant, phytoextraction, phytoremediation, Tagetes erecta L., Helianthus annus L., Amaranthus caudatus L. IntroductionIntensive development of the civilization has been accompanied by the contamination of the environment with heavy metals, including nickel. Large amounts of nickel are transferred to the environment by combustion of liquid fuels, petroleum products and other fossil fuels as well as extensive applications of this metal in the metallurgical industry (eg anticorrosive coats) and as a catalyst in organic syntheses [1], which indicates that urbanized areas are at a particular risk of elevated nickel emissions. In Poland plants capable of phytoremediation of heavy metals are searched for, as they may decontaminate the environment in our moderate climate. As it was reported by [2], most species suitable for phytoremediation purposes belong to the families Brasicaceae and Fabaceae. When analyzing the urban landscape we may observe increasing efforts to enhance the aesthetics and appearance of green areas, providing applications for such ornamental plant species, which may improve the structure and reduce contamination of soils in the city. Additional factors determining the selection of species for urban plantings should include a given plant's capacity to survive and function normally in the environment seriously contaminated with heavy metals and phytoextraction capacity, ie the accumulation of large amounts of metals in the aboveground parts. Studies on plants capable of decontaminating urban soils from heavy metals were conducted eg by [3][4][5][6][7][8][9].Attractiveness of the technology using ornamental plants for the remediation of contaminated environments was an incentive for the investigations conducted within this study. Analyses were conducted on three commonly used species of ornamental plants growing on soils co...