The investigation was carried out in greenhouse with tomato cv. ’Cunero F₁’ grown in rockwool, peat and sand substrates with fertigation system without recirculation. In this research nutrient liquid with or without chlorine was tested. The experiment showed no significant differences on the total, marketable and unmarketable yield of plants fertilized nutrient liquid with or without chlorine. The highest yielding of tomato in rockwool, while lowest in sand substrates was detected. The higher weight of one tomato fruit in peat substrate, compare to sand, was observed. Both substrates and kind of potassium fertilizing had no significant effect on the number fruits per plant.

In the experiment with greenhouse tomato cv. ’Cunero F₁’ the effect of nutrient liquid with or without chlorine on the chemical composition of leaves and fruits was investigated. In research rockwool, peat and sand substrates with fertigation system was used. The experiment showed higher potassium, calcium, magnesium and chlorine leaves content in tomato fertilized nutrients liquid with chlorine. Kind of potassium fertilization had no significant effect on the chemical composition of tomato fruits. Lowest witamin C, total nitrogen and potassium content in fruits of tomato grown in sand substrate was detected, compared with peat and rockwool

Blueberries are tasteful fruits and are widely believed to be the source of health beneficial compounds, especially phenolics. Freezing is one of the methods of prolonging their supply beyond vegetative season. The aim of the study was to estimate fruit chemical composition of four blueberry cultivars (‘Spartan’, ‘Bluecrop’, ‘Jersey’ and ‘Blueray’). Dry weight, total sugar, total acidity, vitamin C and total polyphenol content were determined in fresh berries and after 6 and 12 months of freeze-storage at –25 ⁰C. In generally, ‘Bluecrop’ berries showed the most stabile chemical composition (dry weight, total sugar, total acid content) whereas ‘Spartan’ ones the least. Considering the all storage period the least pronounced changes occurred in total acid content (increase by 0.1 g citric acid ∙ 100g^-1) while the most substantial in vitamin C content, decrease by 57% (‘Bluecrop’) –72% (‘Jersey’).

The published results on plant propagation m vitro culture show the importance of maternal plant age in a successful regeneration process. It is known that initiation effectiveness is low when primary explants are taken from old trees. The aim of this study was an attempt to regenerate Syringa vulgaris from an old specimen of Dendrological Garden in in vitro culture. April turned out to be the optimal month for collecting explants. The highest percentage of initiated shoots were obtained on MS medium containing 7.5 mg×dm^-3 BAP and 0.02 mg×dm^-3 NAA. The highest propagation efficiency was received on MS medium with a double amount of MgS0₄ supplemented with 1.0 mg×dm^-3 BAP. Insignificant effects were observed on the media with cytokinin BAP. The plants with the best-developed root system were obtained on MS medium with reduced to ¼ amount of macro- and micronutrients supplemented with 5.0 mg·dm^-3 IBA.

The experiment was carried out at the Department of Ornamental Plants in the Agricultural University in Lublin in the years 2000–2002. The plant material was corms of Acidanthera bicolor var. murielae Perry with a circumference of 8–9 cm, which in number of thirty was planted on a plot 1.2 m², at 8 cm of depth in the second week of May. According to the scheme of experiment: linuron 1.000 kgּha^-1, pendimethalin 0.990 kgּha^-1 and napropamide 1.500 kgּha^-1 were applied one week after planting the corms of the research plant. Next day some plots were mulched with 5 cm thick layer of pine bark or peat. The experiment included also a control set without herbicides and mulches, which it was hand weeded and a control set with delay hand weed performed three week late compared with the rest plots. At the end of vegetative stage the measurement was carried out on 10 plants of each plot including: length of flower stem, number of flowers and length of spike. It was noted that linuron, pendimethalin and napropamide did not injury to plants of Acidanthera bicolor. Application of linuron and pendimethalin beneficially influenced on number of flowers (respectively by 9.65 and 9.72 piecesּplant^-1), length of flower stem (respectively by 102.54 and 101.52 cm) and length of spike (respectively by 40.14 and 40.28 cm). Besides application of napropamide had a positive effect on received of greater number of flowers (9.40 piecesּplant^-1) and longer spike (39.60 cm). Delay of hand weed about three weeks had a negative effect on yield and quality of flowers of the research plant which formed the smaller number of flowers and the shortest flower stems and spikes (respectively by 8.4 piecesּplant^-1, 96.2 cm and 35.4 cm). It was received the longer flower stems in combinations where applied of pine bark or peat as a mulch (respectively by 100.88 and 100.23 cm) in comparison with combination without mulch (97.96 cm). There was no noted considerably influence of organic mulches on number of flowers in spike and length of inflorescence.

Studies were conducted at the Experimental Station of the Agricultural University of Lublin in the years 1997–2000 the aim of which was to estimate the quality of young trees and the nursery eficiency of cherry trees on 6 stocks: P-HL 84 (A), P-HL 6 (C), Colt, F 12/1, mahaleb cherry (Prunus mahaleb L.) and sweet cherry (Prunus avium L.). The highest percentage of the taken buds was found on P-HL 84, P-HL 6 and F 12/1. The budding of the enumerated stocks every year makes it possible to achieve the greatest nursery efficiency. More than 78% of first quality trees were obtained on stocks Colt and mahaleb cherry. The worst quality cherry trees of cv. ‘Łutówka’ were obtained on vegetative clones P-HL 84 and 6 as well as F 12/1.

A vegetation experiment was conducted in 2001–2002 in an unheated greenhouse on the effect of differentiated nitrogen fertilization on yield and quality of garden rocket. Nitrogen was used in three forms, i.e. lime saltpeter, urea and ammonium sulphate, and in three doses: 0.2; 0.4; 0.6 N∙dm^-3 (2001) and 0.25; 0.50; 0.75 g N∙dm^-3 (2002). The plants’ growth, yield and content of nutrients were evaluated and an chemical analysis of the substrate after the harvest was conducted. The studies pointed out a possibility of cultivating garden rocket in autumn in an unheated greenhouse. A higher yield of fresh weight was obtained in the treatments with lime saltpetre and urea as compared with ammonium sulphate. Increased doses of nitrogen, independently of the kind of the applied fertilizer, caused a decrease of the yield of rocket fresh weight. The studied plants of garden rocket were characterized by a high content of dry matter, vitamin C, protein, potassium and calcium. The content of nitrates in the dry matter of leaves was within the range 0.02–0.98%, depending on nitrogen dose and the year of studies. The application of 0.2–0.25 g N∙dm^-3 of the substrate in the autumn cultivation of rocket proved to be the most advantageous in view of the highest yield of fresh weight, the highest content of vitamin C and the lowest proportion of nitrates in the leaf dry weight.

Shoot tips of Tibouchina urvilleana Cogn. were cultured 4 weeks in vitro in modified Murashige and Skoog (MS) [1962] medium supplemented with growth retardants: paclobutrazol – 0.1, 0.5, 1.0, 5.0 mg∙dm^-3, flurprimidol – 0.1, 1.0, 5.0 mg∙dm^-3, chlorocholine chloride (CCC) –5.0, 50.0, 250.0 mg∙dm^-3. Explants cultured on the medium without growth substances were used as a control. Rooted microcuttings were transferred to the greenhouse and transplanted into a mixture of 1 peat :  1 perlite, where they were grown for 5 weeks. Plants were then cultivated in a peat substrate during another 5 weeks. Acclimatization of rooted shoots in the greenhouse was affective in 92.5–100%. The survival of plants was lowest when microcuttings were previously cultured on medium with flurprimidol at 5.0 mg∙dm^-3. Cultivation of Tibouchina urvilleana shoots in vitro on media with various growth retardants had a significant effect on the further growth of plants ex vitro. Paclobutrazol and flurprimidol at 5.0 mg∙dm^-3 inhibited very strong growth of plants after 10 weeks of growth ex vitro.

The purpose of the studies was to determine the occurrence of soilborne fungi pathogenic towards onion cultivated after spring rye and common vetch. The objects of the studies were the seedlings of onion ‘Wolska’ cv and the isolates of the following fungi: Fusarium culmorum, F. oxysporum, F. solani, Penicillium verrucosum var. cyclopium, P. verrucosum var. verrucosum and Pythium irregulare. As a result of the growth chamber studies it turned out that the fungi used in the experiment were pathogenic towards onion. The harmfulness of the studied fungi varied both between the species and between the isolates within the species. P. verrucosum var cyclopium and F. culmorum proved to be the most harmful since the smallest number of onion plants grew in those experimental combinations and they were the least infected. The most onion plants with the smallest proportion of the infected ones were found in the combination with F.  oxysporum.

Studies were conducted at the Felin Experimental Station of the Agricultural University in Lublin in the years 2001–2003 and their aim was to estimate the effect of preparations Arbolin 036SL and Promalin 3,6 SL in the form of lanolin paste on the quality of two-year-old trees ‘Š ampion’ and ‘Jonica’ cvs. grafted on rootstock M.26. It was shown that the greatest influence on the number of lateral shoots, sum of shoot length and their mean length was exerted by the cultivar and atmospheric conditions in a given year. It was observed that in the majority of trees more lateral shoots were formed by the trees after the application of growth regulators as compared to the control. A singular use of preparations stimulating the branching in the form of lanolin paste in the years with unfavourable weather conditions (2003) was not sufficient to obtain satisfactory effect. The genetic features of a cultivar and the weather conditions in the period of young shoots’ growth had a significant effect on the growth of the studied trees. Preparations Arbolin and Promalin in the form of lanolin paste had no significant effect on the diameter of the rootstock trunks.