The aim of present paper was quantitative evaluation of triterpenoid saponins – oleanosides occurring in leaves, inflorescences and rhizomes of annual and biennial Silphium perfoliatum L. plants. It was found that all studied above and underground organs contained triterpene saponins whose aglycone was oleanolic acid. It was proven that leaves of Silphium perfoliatum L. contained the highest amount of oleanosides as compared to inflorescences and rhizomes and thus they could be an attractive source for pharmaceutical industry. It was also found that oleanoside level in leaves decreased along with the plant’s development.

Five clones of a new interspecific hybrid Hippeastrum × chmielii Chm. obtained by crossing Hippeastrum hybridum with Hippeastrum pratense were compared. Content and distribution of chlorophylls, carotenoids and anthocyanins were determined in fresh perianth leaves using spectrophotometric method and calculated on dry mass basis. Separation and identification of anthocyanidins were done by TLC on cellulose plates against standards. Variations in intensity and shade of perianth leaves colour were due to differences in content and distribution as well as copigmentation in three studied classes of the pigments.

The influence of green manures in form of forecrops (oat, vetch, field pea, and mixtures these of plants) and farmyard manure on crop and the content of dry matter and mineral elements in white cabbage, was examined. The highest yields of white cabbage were obtained after the ploughing the mixtures of vetch, oat and field pea and of vetch and field pea, and farmyard manure. The highest content of nitrogen was characterized by cabbage cultivated after mixture of vetch with oat and field pea, and vetch. One could notice more magnesium in cabbage cultivated after on organic fertilization than without it. Ploughing of all biomass of green manures influenced more profitably on the content of magnesium. The kind of organic fertilization did not influence the content of dry matter, phosphorus, potassium and calcium in white cabbage.

The research was conducted in a mushroom growing facility located in Krasne near Rzeszow, consisting of three production halls. The halls had identical thermal and humidity conditions but different composts (dices 1, dices 2 trademark artificial substrate, conventional substrate), and casings soil (thermally disinfected, chemically disinfected, thermally and chemically disinfected). Fragments of spawn of Agaricus bisporus, compost and casings were put on Petri dishes with acidified PDA nutrient medium. Besides, in relative aseptic conditions, Petri dishes with glucose-potato medium acidified (with 50% lemon acid) and not acidified were prepared. They were placed on upper and middle shelves in four randomly chosen places in each hall. Four Petri dishes with acidified an four with not acidified medium were put in each such point, they were opened and left there for 40 hours, then they were closed and kept in thermostat for 2 weeks. Analyses were carried out at following dates: A – prior to casing application – 16 days after dice and conventional compost were laid, B – during third harvest – 3 weeks after production cycle start. The number and species composition of microorganisms which accompany the mushroom cultivation depended on the healthiness of: the compost, casing and spawn of Agaricus bisporus. The artificial substrates recommended for common mushroom cultivation are not always free from harmful microorganisms and the spawn of Agaricus bisporus which they contain Trichoderma spp may also be paralysed. by the pathogenic species. Precise double disinfecting of the casing – with steam and chemical – eliminates completely Trichoderma spp. Verticillium spp Mycogone perniciosa the species harmful to common mushroom. The presence of competitive and pathogenic fungi in the cultivation halls already at the beginning of the production cycle is a serious thread of the cultivation of common mushroom because their rapid spread shortens the span of fruiting body harvests.

The present research investigated the number of chromosomes in the cells of apical meristems of roots for three original Dendranthema grandiflora Tzvelev cultivars and the derivative cultivars obtained due to radiomutation. It was shown that only in one mutation cultivar, ‘Bronze Wonder’, the number of chromosomes differed from that of the original cultivar, ‘Lilac Wonder’.

The study into vitamin C content were performed on plants grown in the Department of Horticulture in University of Warmia and Mazury in Olsztyn in 1998–2000. A field experiment was conducted to study the effect of different factors such as species, cultivar, date and site of growing, growing method, foliar nutrition, time of storage on the accumulation of L-ascorbic acid in edible parts of vegetables. Twenty vegetable species grown in fields and in unheated plastic tunnels were studied. The content of the acid was estimated by the Tillmans method [Pijanowski et al. 1964]. The analyses showed a widely varied content of vitamin C in vegetable crops and the levels depended mainly on the species. Paprika berries had the highest content – over 100 mg·100 g^-1. The lowest content of vitamin C was found in scorzonera, salsify, soybeans and cucumber with below 6 mg per 100 mg of fresh mass in 1998. The effect of different cultivation methods on cucumber and lettuce leaves showed no regularities in vitamin C content changes in particular years of the experiment. However, the effect of cabbage cultivar and storage conditions on vitamin C content in cabbage was noted. The L-ascorbic acid content was 33.4 mg·100 g^-1 in ‘Kamienna Głowa’ and 48.4 mg·100 g^-1 in ‘Litewska’ cabbage. The losses in vitamin C during after 60 days of inadequate storage were from 12.9 to 52.8%. The effect of summer planting date on the content of vitamin C was also shown in two radish cultivars, where ‘Murzynka’ radish was characterised by a higher vitamin C content. The foliar nutrition gave positive results and increased the vitamin C content in redbeet.

In horticultural production substrates have been sought that would ensure the optimum physical conditions (including aerobic and aquatic) in the root environment. The soil substrate can be modified with synthetic supplements called hydrogels or sorbents. When introduced to the soil, they improve the growth and development of plants, and by interacting with the climatic and soil conditions, they can improve the chemical composition of the vegetables. Research conducted in 2000–2001 aimed at the evaluation of the effect of different type sorbents introduced into the soil and the cultivation date on the concentration of some components in the Charlene lettuce cultivated in a film tunnel. Lettuce was grown in the presence of the following sorbents: potassium Ecosorb, sodium Acrygel, potassium Acrygel and sodium-potassium Acrygel during two terms: spring (April–May) and autumn (September–October). Based on the results of the two-year experiment, a significant effect of both experimental factors on the concentration of some components in the leaves of Charlene lettuce was observed. The concentration of L-ascorbic acid was determined by the type of sorbent used. In the first year of the experiment, the sodium-potassium Acrygel (14.2 mg%) was used to enhance the accumulation of vitamin C. In the second year, the sodium Acrygel (12.5 mg%) enhanced the accumulation of vitamin C. The spring plants accumulated higher levels of total sugars (in 2000 – 1.51% more, in 2001 0.68% more) in comparison to the autumn plants. The lettuce grown in the autumn had high concentrations of nitrates, averaging 2944.3 mg N-NO₃·kg fresh mass^-1.

Series of experiments were carried out on 5 varieties of a root celery in order to evaluate the content of nitrates in the root’s swellings – after harvest and storage (the method of colorimeter was used). The investigations revealed that the content of nitrates in the root’s swellings was increasing accordingly to growing doses of N – fertilisation. It was stated that some impact on the increase mentioned had also genotype of tested varieties. No peculiar susceptibility of the root celery to accumulate nitrogen compounds was observed, during the experiments.

The applicability of 30 cultivars of Dendranthema grandiflora Tzvelev to shape the habit typical for the Sombrero group was investigated. Controlled plant cultivation was carried out in spring and in summer. A plant habit similar to the Sombrero type was obtained in the following cultivars: ‘Eleonora Lilac’, ‘Kodiak’, ‘Kodiak Yellow’, ‘Miral’, ‘Mirage’ and in ‘Spider Yellow’.

Cuttings of tomato ‘Recento F₁’ cultivar were rooted in water, placed under fluorescent lamps emitted daylight, yellow, green, blue and white light with quantum irradiance 57 ?mol m^-2s^-1. The rooting rate and quality of roots were investigated. It was observed a favourable influence of the blue, daylight and white light on the length, number and mass of roots. Yellow and green light influenced unfavourable on the mass and number of roots.

Transplants of tomato cultivar ‘Recento F₁’ were grown under the fluorescent lamps emitted daylight, yellow, green, blue and white light with quantum irradiance on the apical bud level 57 ?mol m^-2·s^-1. The growth dynamic and the most important morphological attributes of the transplant were investigated. It was observed favourable influence of the blue light. Plants exposed to blue light flowered early, were short, with thick and strong stem, shortened internodes, enhanced participation of the dry mass in fresh mass. Yellow light influenced unfavourable. Plants grown under yellow light had delicate stem, small leaves, reduced fresh and dry mass and flowered late. Employment of the blue light emitted lamps can be an efficient method of the tomato transplant growth control.