The experiment with ‘Boro F₁’ red beet was aimed at determining the effect of the kind of nitrogen fertilizer (RSM, ENTEC 26) and the manner of application (broadcasting/liquid spreading, with / without foliar nutrition) on the content of protein nitrogen in roots, and ammonium and nitrate nitrogen content in leaves and roots of red beet. The kind of applied fertilizer did not have any influence on the size of examined parameters. In 2005 foliar nutrition with nitrogen caused a decline in nitrate concentrations in leaves and roots of the plants in comparison with unnourished objects; however, such correlation was not corroborated in the following years of the cultivation. Quantities of all examined parameters were diversified depending on the cultivation year.

The examinations were aimed at determining the dependence between form and rate of applied nitrogen fertilizer vs. yield and chemical composition of leaves of Swiss chard cultivated in greenhouse in spring. Nitrogen was applied in a form of urea, potassium nitrate, and ammonium nitrate at three amounts: 0.2; 0.4; 0.6 g N·dm^-3 of substrate. Following items were assessed: yield, nutrients contents, as well as chemical analyses of substrate after plant harvest were made. Increase of nitrogen rate in objects with potassium nitrate and ammonium nitrate resulted in the decrease of fresh matter yield, while in objects with urea, the yield remained at constant level. The highest yield of above ground parts (356 g·plant^-1) was achieved by fertilizing the plants with the lowest nitrogen rate (as ammonium nitrate). Contents of nitrates in leaf dry matter was within the range of 0.59–1.27% depending on nitrogen rate and form. The highest nitrate levels were found when potassium nitrate was applied as fertilizer, whereas the lowest – when applying ammonium nitrate; however, regardless the fertilizer type, higher rates caused the increase of nitrate contents. Studies revealed that at increasing nitrogen concentration in a substrate, level of vitamin C also increased. Contents of N, P, K, Ca, and Mg in Swiss chard’s leaves depended on nitrogen fertilizer type. Comparison of studied factors influence on potassium concentration in plants indicated that increasing nitrogen rates in objects with urea and ammonium nitrate was accompanied by the decrease of this element content. An inverse dependence was recorded in objects with potassium nitrate, where content of potassium in Swiss chard’s leaves increased along with the nitrogen level increase. Application of 0.2 g N· dm^-3 substrate appeared to be the most profitable in spring cultivation of Swiss chard, because the largest yields of fresh matter and the lowest share of nitrates in dry matter of studied plant were found.

In pot experiments, in spring 2006 and 2007, a comparison was made between the chelated and the mineral forms of copper on the yielding of lettuce and on the content of Cu, Zn, Mn and Fe in lettuce leaves. Plants were grown in peat substrate supplemented with Cu doses of 5, 25, 50 and 75 mg∙dm^-3. A greater mass of lettuce heads was obtained after the application of the mineral form of copper. In the range of doses: 5–50 mg Cu∙dm^-3, the mean yields of lettuce did not differ. In the second year of studies, the application of copper chelates in the dose of 75 mg∙dm^-3 caused a high reduction of yield. The mean copper content in lettuce, after the application of the chelated Cu form, was twice higher than after the use of the mineral Cu form. Iron content in lettuce after the application of copper chelates was higher than after the use of copper sulphate, while the contents of zinc and manganese were smaller.

In four-year-lasting field experiment yielding and chemical composition of goldenrod (Solidago virgaurea L. ssp. virgaurea) herb depending on different methods of plantation establishment and natural growth regulator Atonik application were analysed. In the experiment different methods of goldenrod plantation establishment were compared: A. direct spring diaspores sowing, B. spring planting of seedlings, C. direct autumn diaspores sowing, D. autumn planting of seedlings as well as spraying with 0.1% solution of Atonik twice a year. Diaspores were sown directly onto the field in rows 40 cm apart, whereas seedlings were produced in multicell trays in plastic tunnel throughout 5 weeks and then transplanted onto the field in 40 cm × 15 cm raw spacing. Raw material was harvested every year at the beginning of blooming stage and after that chemical analyses comprised leiocarposide content (by HPLC method) were done. The highest yields of raw material were obtained in the second and third years of cultivation, while in the fourth year a considerable yields decrease was observed, indicating that goldenrod plantation should last two or three years. Higher raw material yields characterized by higher leiocarposide content were collected from the plots with spring seedlings transplanting or autumn diasporas sowing, thus these methods of plantation establishment should be recommended on commercial plantations of goldenrod. Additionally, plants should be sprayed with 0.1% Atonik in order to increase raw material yields.

Studies were conducted on a field of soybean monoculture at Czesławice near Nałęczów in the years 2002–2004. The object of the studies were soybean plants ‘Polan’ cv. and chitosan. A water solution of chitosan micro-gel at the concentration of 0.1% was used for studies. The studies tested the effect of this compound on the inhibition of soybean diseases caused by soil-borne pathogenic fungi. The solution of chitosan was used a few times, i.e. for seed dressing, seedling spraying, plant spraying at anthesis and in mixed combinations. During the experiment field observations were conducted in particular developmental stages when the number and healthiness of plants were established. Infected plants were submitted to mycological analysis. Results from the field observations and mycological analyses showed that chitosan used in a mixed combination (for seed dressing + seedling spraying + plant spraying at anthesis) was the most effective in protecting soybean from the infection of soil-borne pathogenic fungi. In those combinations the best density of soybean seedlings and plants at anthesis was obtained. The mycological analysis of infected parts of soybean seedlings and plants at anthesis showed that chitosan proved effective in inhibiting the infection of soybean plants from fungi from the genera of Fusarium, Pythium, Phomopsis and Botrytis cinerea, Sclerotinia sclerotiorum and Rhizoctonia solani.

The effect of BA on the flowering of Campanula persicifolia L. ‘Alba’ cultivated in an unheated plastic tunnel and in the field was examined. BA in the concentration of 100, 200, 400 mg∙dm^-3 was applied on the leaf twice in both years of the experiment duration. Plants not treated with benzyladenine were used as a control. It was concluded, that cultivation of Campanula persicifolia L. ‘Alba’ in an unheated plastic tunnel causes growth of fewer inflorescence stems but of better quality than in the field. Application of benzyladenine in the concentration of 400 mg∙dm^-3 in Campanula persicifolia L. cultivation in an unheated plastic tunnel results in an increased fresh weight of inflorescence stems and number of primary side stems. Application of benzyladenine in the concentration of 400 mg∙dm^-3 is recommended for Campanula persicifolia L. cultivated in the field due to better branching in the first and second year of flowering. Application of benzyladenine in the concentration of 200 and 400 mg∙dm^-3 on the leaf of Campanula persicifolia L. cultivated in the tunnel leads to the production of shorter inflorescence stems in the first and second year of flowering. In the field, only the older plants (in the second year of flowering) react similarly.

The aim of the research was to determine the quantitative and qualitative composition of the communities of fungi and bacteria formed in the soil under the influence of onion cultivation, with consideration to various options of conserving cultivation, using spring rye and common vetch as after-crop cover plants. Moreover, in the laboratory tests, the occurrence of microorganisms characterizing by an antagonistic influence on pathogenic fungi with a facultative parasiting was established. As a result of the laboratory microbiological analysis it was found out that particular soil samples taken from under the cultivation of onion differed with the qualitative and quantitative composition of microorganisms. Spring rye stimulated the growth and development of microorganisms, especially antagonistic ones (Bacillus spp., Pseudomonas spp., Gliocladium spp., Trichoderma spp.), and common vetch caused an increase of the number of cfu of pathogens (Alternaria alternata, Fusarium culmorum, F. oxysporum, F. solani, Penicillium spp., Pythium irregulare).

Robinia pseudoaccacia plants grown hydroponically were treated Pb(NO₃)₂ with 15, 45 mg Pb²⁺ ∙ dm^-3. After 6, 12, 24, 72 hours of the metal treatment the plants were collected and dissected organs. The plants accumulated and transported to ground part 0.88% and 1.35% of total accumulated lead for the lower and higher dose of Pb²⁺ respectively. The level of GSH was differed and depended on organs, dose and time treatment of Pb²⁺. We investigate (different pattern of expression) expression of RpGSH1 and RpPCS genes in roots. The study showed that glutathione and genes encoded enzymes connected with synthesis of him, plays important role in the process of detoxification in plant.

An assessment was made of the usefulness for forcing of five cultivars of Hyacinthus orientalis L.: ‘Carnegie’, ‘City of Haarlem’, ‘Delft Blue’, ‘Jan Bos’, and ‘Lady Derby’. The bulbs were planted on 14 October 2003 and 2004 in Flexy-tray type of pallets filled with water and in plastic boxes with a standard medium. The bulbs were cooled for 12 or 14 weeks. It was found that forcing lasted shorter in the water-filled trays, while longer inflorescence stems were obtained in plants forced in the standard medium. The cooling of the bulbs for 14 weeks resulted in the shortening of the forcing time and in the lengthening of inflorescence stems.

Asparagus plants cv. “Epos” were planted in the aeroponic system with recirculation in two cycles. The effect of asparagus plant age and crown size on fern growth were studied. The results show that the age of asparagus plants affected the number of ferns – the number of assimilation shoots increased with age – while the weight of asparagus crowns had an effect on the number and total weight of shoots. An increase in crown weight by about 1000 g caused an increase in the number of shoots by about 6, while the weight of one shoot increased by approx. 144 g. The age of aasparagus plants was also a significant factor for dry weight, % Brix and total carbohydrate contents in roots before the assimilation season as well as glucose, fructose, sucrose, GFS and total carbohydrate contents in roots after the assimilation season.

In presented studies was undertaken the attempt to determine the effectiveness of such preparations as Biochikol 020 PC and Biosept 33 SL in limiting the growth of T myrtilli in vitro. Moreover, the protective effect of these biopreparations and Dithane M45 80WP for highbush blueberry stems was determined. The studies carried out in vitro indicated that Biochikol 020 as well as Biosept 33 SL significantly limited the growth and development of pathogen. Very strong inhibition of hyphae growth and its deep degradation were caused by Biosept 33 SL in concentration 0.3%. Similarly, in experiment on protecting action of selected preparations for stems of highbush blueberry against T. myrtilli, Biochikol 020 and Biosept 33 SL inhibited the growth of pathogen. But its protective effects were weaker in comparison to Dithane M45 80WP because after the application of this preparation the development of disease symptoms caused by T. myrtilli was significantly lower.