In the world of plants frost is a particularly dangerous phenomenon. Destructive effect of frost on plants is both direct and secondary. The amount of damage done by frost depends on its intensity, frequency, a season of its occurrence and a plant species. The aim of the work was to find spatial and temporal distribution of ground frost in Poland and to determine effect of minimum air temperature at the ground level on the dates of phenological phases and harvesting and duration of development stages and also on the quantity of cucumber yield of pickling cultivars at the turn of the 20^th and 21^st centuries. Source materials used in the present study were collected from 28 experimental stations of COBORU and from 51 meteorological stations of IMGW in the years 1966–2005. Ground frost was characterised, e.g., by means of average dates of last spring and first autumn frost, duration of the period without frost and also intensity and frequency of its occurrence and a linear trend. Effect of minimum air temperature at the ground level on the growth, development and crop productivity of cucumber was determined with the use of linear and curvilinear regression analysis and the linear trend of occurrence of last spring and first autumn frost and duration of the period without frost with the use of linear regression analysis. Ground frost poses high potential risk for field cultivation of cucumber in Poland not only because of the fact that it significantly determines the rate of growth, development and yield quantity of the plant but also because of its high spatial and temporal variability; the highest cultivation risk occurs in north-eastern Poland where significant shortening, year by year, of the period without frost was proved and where the highest frequency of frost occurrence both at the beginning and at the end of the cucumber growing season is recorded.

The use of synthetic materials for mulching is a very common practice for vegetable crops. Soil mulching influences the microclimate around plants and soil environmental conditions. Mulching with black materials is particularly recommended for thermophilic species, especially those requiring high soil temperature. An experimet was established to evaluate an effect of soil mulching with synthetic materials (black polyethylene film, black polypropylene nonwoven 50 g∙m, black fabric 94 g∙m^-2) on the fruit quality and nutritive value of two melon cultivars (‘Seledyn’, ‘Yupi’) cultivated in the field under the climatic conditions of central-eastern Poland. The greatest numbers of fruit per 1 m² and marketable fruit were harvested in the year 2007 which was most favourable for melon growing compared with the remaining study years. The number of the fruits which were either unripe or showed symptoms of decay did not differ significantly in individual study years. ‘Yupi’ was characterised by a significantly higher total number of fruit and number of marketable fruit than ‘Seledyn’. ‘Yupi’ fruits were less affected by decay than ‘Seledyn’ which, however, produced significant less unripe fruit. ‘Yupi’ fruits had significantly more dry matter, total sugars, monosaccharides and vitamin C as compared to ‘Seledyn’. In both the cultivars examined, higher nutrient contents were determined in the fruit grown using black film mulching.

Mushrooms are cultivated on a wide range of materials of organic origin. Textile industry wastes seem to be interesting in this regard. In experiment, mycelium growth of the following eight mushroom species: Pholiota nameko (Ito) Ito et Imai, Flammulina velutipes (Curt. ex Fr.) Sing., Lyophyllum ulmarium (Bull. ex Fr.) Kumm., Marasmius oreades (Bolt.: Fr.) Fr., Hericium erinaceus (Bull: Fr.) Pers., Agrocybe aegerita (Brig.) Sing., Lentinula edodes (Berk.) Pegl. and Ganoderma lucidum (Curt: Fr.) Karst. cultivated on alder sawdust, rye straw, hemp and flax shive substrates was investigated. Significant variability in mycelium growth was observed depending on the mushroom species and the type of the applied substrate. The best mycelium growth of the examined mushroom species was recorded on flax shive and alder sawdust. In the majority of the experimental mushroom species, the worst growth of mycelia was recorded on the hemp shive substrate.

Cereal straw is used as the most common substrate for Pleurotus ostreatus (Fr.) Kumm. cultivation. However other easily available and cheep materials are being sought. Textile industry wastes, among others, seem to be suitable materials. The effect of the kind of substrate on the mycelium growth, enzymatic activity and yield of Pleurotus ostreatus (Fr.) Kumm. was investigated. The subjects of the studies were the ‘K22’ and ‘P80’ strains of P. ostreatus and four substrates: i.e. alder sawdust, rye straw, hemp and flax shive. The type of substrate was found to affect the examined P. ostreatus parameters. The examined strains responded similarly to the applied substrate type. The best mycelium growth was obtained on the substrate from flax shive. The activity of the laccase enzyme turned out to be the highest on the hemp shive and the same substrate also yielded the highest crop of carpophores. The obtained results corroborated high usefulness of hemp and flax shive for the cultivation of P. ostreatus.

Pepino dulce is a new crop in Poland. Its fruit can be harvested at different stages of ripeness. As the majority of vegetables of the family Solanaceae, pepino fruit is abundant in potassium. The objective of this study was to investigate the effect of increasing potassium rates and fruit ripeness stages on macronutrient content and ratios in the fruit of pepino dulce cv. Konsuelo. Both experimental factors, i.e. potassium fertilization levels and the degree of fruit ripeness, had a significant effect on the macronutrient content of pepino dulce. The highest total nitrogen, potassium and magnesium levels were noted in the fruit of plants fertilized with potassium at a rate of 2 g per plant, while the fruit of plants fertilized with the lowest potassium rate (1 g per plant) accumulated the highest amounts of calcium. The highest phosphorus content was reported in the fruit of non-fertilized plants. Fully ripe fruit contained significantly more nitrogen and magnesium, while unripe fruit had a higher content of phosphorus, potassium and calcium. A close to optimal Ca:Mg ratio (2.4 on average), a narrow Ca:P ratio (from 0.6 to 1.7) and wide K:Mg (from 16.1 to 28.4), K:(Ca + Mg) (from 3.7 to 7.9) and K:Ca (from 4.5 to 13.6) ratios were observed in all treatments.

The aim of investigations conducted in the years 2005–2007 was to determine the chemical composition of nutrient solutions in the root environment of tomato grown in wood fiber and rockwool, under the influence of diverse levels of nitrate nitrogen in the nutrient solution amounting 200, 220 and 240 mg N-NO₃·dm^-3. With an increase in nitrate nitrogen content in nutrient solutions used in plant fertigation a significant increase was observed in the contents of N-NO₃ in nutrient solutions of the root environment, collected from wood fiber and rockwool. No such effect was found for contents of N-NH₄, P, K, Ca, Mg, Fe, Mn, Zn, Cu, B, Na, Cl or pH and EC. In case of wood fiber the following nutrient concentration series was found in nutrient solutions of the root environment in relation to the nutrient solution flowing from the drippers: Na > Cu > Ca > Zn > K > Cl > B > N-NO₃; the following were reduced Fe > Mg > P-PO₄ > N-NH₄ > Mn. Nutrients being concentrated in root environment solutions during tomato growing in rockwool were: Na > Ca > Cu > Fe > Cl > K > Zn > B > S-SO₄ > N-NO₃, while contents of Mg > P-PO₄ > N-NH₄ > Mn decreased. Despite of a wide range of carbon to nitrogen ratio (C:N) in wood fiber (123–127), no significant reduction of nitrates was shown in the root environment. It was a result of adequate application frequency of nutrient solutions during a day.

One of the most important problems in horticultural seed science and technology nowadays is looking for new methods to improve seed quality. Especially interesting are the ones, in which compounds of natural origin are used. One of such groups is ethereal oils from plants. The commercial seed samples of lettuce (Lactuca sativa L. ‘Dumka’) were soaked in 9 different treatments of 5% alcoholic solution of camphor tree (Cinnamomum camphora L.) ethereal oil and 9 different treatments of 5% alcoholic solution of patchouli plant (Pogostemon cablin Benth.) ethereal oil. Then the seeds were routinely tested for seed germination, the length of the received seedlings was also measured and the seeds health status was evaluated. The tested ethereal oils had no effect on the germination of lettuce seeds. However, soaking the seeds in the ethereal oils solutions did decrease the percentage of dead seeds in the tested samples. Soaking of the seeds in the ethereal oils solutions also increased the percentage of healthy ungerminated seeds. Treating the seeds with the concentrations of the ethereal oils solutions, although had no effect on their germination, still shortened the length of seedlings. Moreover, the used ethereal oils lowered the amount of identified Alternaria alternata and Cladosporium sphaerospermum fungi on the seeds.

The production costs force the orchids growers to look for media that could become an alternative for the basic ones. Phalaenopsis plants (ex in vitro) were planted into containers filled with different media: New Zealand sphagnum moss, mixture of expanded clay pellets and New Zealand sphagnum moss (v:v = 1:1) and expanded clay pellets. Originally, orchids were grown in translucent plastic pots of 7 cm diameter (8,5 months) and then, they were transferred to translucent plastic pots of 11 cm diameter and 0.5 dm³ capacity. Effect of medium on the size of plant, hydratation of leaves tissue and flowering was evaluated. Orchids grown in New Zealand sphagnum moss create a significantly greater mass of the aboveground plant part and the roots. Also parameters characterizing the inflorescence and flowers indicate that the most favorable for the orchids is to grow them in sphagnum moss. The least favorable growth conditions were provided by the growing in expanded clay pellets without any additions. In this medium, only 25 to 35% of plants flowered.

Effect of growing media on macro- and microelements, as well as on chlorophyll concentration in Phalaenopsis orchids were investigated. In the years 2006–2008, an experiment on Phalaenopsis orchids cultivation was carried out. The plants were planted into New Zealand sphagnum moss, mixture of expanded clay pellets and New Zealand sphagnum moss (v:v = 1:1), or into expanded clay pellets only. Orchids were grown in translucent plastic pots. Total macro and micro elements concentration in leaves and roots were determined. Furthermore concentrations of chlorophyll a and chlorophyll b in leaves and roots were measured. Growing media exert a significant influence on the nutritional status of Phalaenopsis orchids. The highest concentration of magnesium, iron and copper was found in plants grown in expanded clay, less in orchids grown in the mixed medium and the least in plants grown in sphagnum moss. A higher concentration of nitrogen, phosphorus, potassium, calcium and manganese was found in leaves. Inversely, in roots, there was a higher concentration of magnesium, iron and zinc. Growing media did not affect chlorophyll concentration in leaves and roots of Phalaenopsis.

Due to strong eggplant growth and the formation of large vegetative weight quantities in growing under glass and foil it was deemed useful to conduct studies on the effect of pruning intensity on yielding of this vegetable in rooms. The aim of the foregoing studies was to demonstrate the effect of plant pruning and topping manner on yield quantity and earliness. The experiment was conducted in the years 2001–2003. The study objects were the plants of ‘Epic F₁’ cultivar. Eggplant was grown in rigid foil cylinders of the capacity of 10 dm³ in the peat substrates. The plants were trimmed, managing for one, two, three, four, five, six guiding shoots and in the natural form, without trimming. Topping cut was performed in each combination after the first fruit harvest. The experiment was established and conducted as a two-factor one, in accordance with a complete randomization system: A – pruning method (a = 7), B – topped and non-topped plants (b = 2). Each combination of the examined factors was represented by 20 plants (experimental units). A significant effect of pruning intensity on the quantity and earliness yielding was demonstrated. The highest marketable fruit yield was obtained from plants managed for two (3.82 kg^.m^-2), three (3.98 kg^.m^-2), and four (3.87 kg^.m^-2) guiding shoots. Managing for one guiding shoot significantly decreased the total and marketable fruit number. The highest early yield was collected from plants managed for one and two guiding shoots. A single topping cut performed after the first fruit harvest did not affect marketable yield and marketable fruit number.

Runner bean (Phaseolus coccineus L.) is, after common bean (Phaseolus vulgaris L.), the second most important species, both around the world and in Poland. However, as compared to common bean, runner bean was not so well recognized, which is indicated by reports from literature. Among the most important values of this bean species are large and very large seeds (the weight of one thousand seeds: 900–3000 g), which, with respect to their nutritional value rival common bean seeds. There are forms of it that differ in plant growth type, morphological features of flowers, pods and seeds, as well as in the manner of use – green pods and for dry seeds. On the basis of world literature, results of the author’s own studies, as well as the studies conducted in Poland by her collaborators and other authors, the issues of development biology, agrotechnical and environmental requirements, flowering and pollination of this allogamous species were presented, as well as yielding, sensitivity to herbicides, effect of pathogenic factors upon generative organs, as well as chemical composition of runner bean seeds and pericarp (Phaseoli pericarpium).

Hamburg parsley is a vegetable that can overwinter in the field. One of the factors influencing surviving winter by plants is the selection of cultivar. In the experiment the relationship between winter hardiness of plants and the changes taking place in the structure of the yield obtained in spring was examined, in comparison to the crop harvested before winter, and Hamburg parsley cultivar. From among the plants of examined cultivars the winter conditions were best survived by ‘Bubka’, ‘Ołomuńcka’ and ‘Vistula’. The yield harvested in spring, as compared to that obtained in autumn, did not depend of the plants’ winter hardiness. Postponing the harvest term to spring decreased the quantities of obtained yields. From among the examined cultivars, only ‘Vistula’, ‘Eagle’ and ‘Ołomuńcka’ plants formed larger marketable yields of roots in spring. In the yield collected in spring there were more I class marketable roots (Ø30–60 mm), and less small ones (Ø< 20 mm). The participation of bifurcated and rotted roots was also greater. Overwintering of plants caused the decrease of leaf yield quantity, with simultaneous improvement of marketable quality.

Zinnia elegans is an annual plant recommended for cultivation for cut flowers as well as flowerbeds. This ornamental plant can be infected by: viruses, bacteria, phytoplasms and by a number of fungi species. Presented studies were conducted in 2006 in three localities of the Lublin region: in the vicinity of Zamość, near Krasnystaw and near Opole Lubelskie. Those studies included three cultivars of Zinnia elegans Jacq.: Golden Dawn, Lawa, Scarlet Flame as well as the mixed material of the cultivars belonging to the dahlia group. Six weeks after the sowing, the seedling’s healthiness was assessed. The proportion of seedlings with disease symptoms ranged from 7% to 44%. The main cause of root infection at the seedling stage proved to be the species of F. equiseti and S. sclerotiorum. Considerable amounts of B. cinerea and F. culmorum and A. alternata were also detected from diseased seedlings. Studies on the susceptibility of analyzed cultivars and the mixed material of elegans zinnia to infection by B. cinerea and F. avenaceum, F. culmorum and F. equiseti were conducted in a growth chamber. Results obtained from this experiment confirmed considerable harmfulness of the species B. cinera and F. equiseti towards the seedlings of elegans zinnia, which can be reduced introducing less susceptible varieties to the cultivation. However, none of the studied varieties of elegans zinnia, only its mixed material, showed such properties.

The aim of the paper is to construct a model which describes the life expectancy of privet sawfly females (Macrophya punctumalbum L.), including additional information on the number of eggs. The data on life expectancy of females and their fertility were obtained in the course of research on the bionomy of the privet sawfly. A variety of discrete distributions to modelling the lengths of life was provided, namely: the Poisson Distribution, the Negative Binomial Distribution and the Poisson-inverse Gaussian Distribution. The analysis the above distributions were applied along with the GAMLSS (Generalized Additive Models for Location, Scale and Shape) and the resulting models were compared with the use of the Global Deviance criterion, the Akaike information criterion and the Schwarz Bayesian criterion. For the best model the expected value and the standard deviation were defined. The profile deviance plot of this parameters, analysis of the residuals, kernel density and Q-Q plot are presented, too. All analyses were performed in R with the GAMLSS package.

Temperature is a factor which strongly affects the yield and broccoli head quality. Temperature determines the date of head initiation and thus affect the length of vegetation period. An experiment the aim of which was to assess the impact of temperature on the yield and the length of the period from the broccoli head initiation until the beginning and end of harvest as well as the length of the harvest period was carried out in years 1997–1999. The seedlings of cv. Fiesta were planted in April, May, June and July. The phase of head initiation was determined on the basis of analyses of microscopic preparations. The highest total yield was obtained from May and June planting dates, the highest marketable yield was recorded in the case of the May date planting. A higher correlation was found between the sum of temperature and mean daily air temperature in the period from the initiation to the beginning and end of harvest and mean weight of marketable heads than between temperature and the total yield. The highest correlation was determined between the mean air temperature and the number of days from the head initiation to the last harvest.

A diversity of active substances that are in the artichoke plants includes it into the group of medicinal plants of broad-spectrum performance. The research conducted in the years 2006–2008 included valuation of poliphenolic compounds content in different parts of artichoke plants during vegetative and generative growth (roots, petioles, leaves, immature and flower at beginning of flowering). The total content of poliphenolic compounds in the reduction on caffeic acid was marked in dried herb with the spectrophotometrical method with the Arnova reagent. The content of poliphenolic acids (caffeic, chlorogenic, ferulic and cynarine) was marked with high performance liquid chromatography (HPLC). The undertaken studies show that there are significant differences with respect to the content of poliphenolic compounds in different parts of artichoke plants. Definitely more total phenolic acids were accumulated in leaves during the vegetative growth (3.167% on average) and in young, immature buds during generative growth (3.730% on average). The chlorogenic acid and cynarine were the main compounds among poliphenolic acids. The content of poliphenolic acids was decreasing with age of plants as young immature artichoke buds had more chlorogenic acid and cynarine than mature heads at the beginning of flowering. The content of caffeic and ferulic acids in the artichoke herb depended on the growth phase of plants. Plants accumulated more caffeic acid in leaves during vegetative growth and ferulic acid in buds during generative growth.

The nutritional value of some vegetables may greatly vary depending on the cultivation method and kind of fertilization. In 2007–2009 there was conducted a field experiment to evaluate the effects of nitrogen fertilizers (ammonium nitrate, calcium nitrate, ammonium sulphate, urea, Entec-26) and their doses (80, 160 kgN∙ha^-1) on yielding and biological quality of two spinach cultivars (Spokane F₁, Rembrandt F₁) grown for autumn harvest. The use of Entec-26 fertilizer assured the highest mean marketable yield of spinach (12.25 t∙ha^-1). Comparable results were observed for ammonium sulphate and ammonium nitrate while lower yield was obtained in treatment supplied with calcium nitrate. The highest accumulation of nitrates and vitamin C was associated with the application of calcium nitrate and the lowest one with ammonium sulphate and Entec-26. An increase of the dose of fertilizer from 80 to 160 kg N∙ha^-1 did not significantly affect yielding of spinach and its nutritional value expressed by the content of dry matter, vitamin C and nitrates. Among the two cultivars, Rembrandt F₁ produced higher yield of leaves and showed some tendency to a higher accumulation of nitrates, whereas lower content of dry matter and vitamin C. The levels of P, K, Mg and Ca were not dependent on the cultivar as well as kind and dose of nitrogen fertilizer.

Eggplant is grown in Poland mainly under shields because of high requirements in climat conditions. The utilization of mulches has played a great role in production of such vegetables. In 2008–2009 there was investigated the yielding of eggplant cv. Epic F₁ cultivated with living mulches – perennial ryegrass and white clover, which were sown three weeks before eggplant planting, in the term of planting and three weeks after planting, as well as with synthetic mulches: polyethylene black foil and non-woven polypropylene agrotextil. The experiment was established according to randomized split – plot method. Marketable yield of eggplant cultivated with the use of black foil was higher than that from the control treatment and mulched with black agrotextil cover by 7.8% and 10.4%, respectively. Eggplant yield obtained from cultivation with white clover was similar to that coming from plots covered with black foil. Cultivation of this vegetable with perennial ryegrass resulted in significant decrease in eggplant yield, average by 17% in relation to cultivation with the remaining mulches and by 15% as compared to control treatments. The content of reducing sugars and magnesium in eggplants fruits depended on the type of mulch and term of living mulches sowing, and in the case of potassium on the species used as living mulch.

Fertilizing cultivable plants is an effective way of improving yield quantity and quality. The studies conducted in the years 2008–2009 were aimed at determining the relationship between the kind of nitrogen fertilizer, manner of its application, as well as the dose of calcium carbonate and the plant unit weight, as well as chemical composition of spinach beet, grown in glasshouse in the spring period. Nitrogen was applied in the form of ammonium sulphate and urea in a localized form (N-deposit) and in the form of solution. Calcium was administered in the form of calcium carbonate in the doses of 5 and 15 g · dm^-3 of substratum. The length of leaves, plant unit weight and selected parameters of beet leaf utility value were assessed. The substratum was also analyzed after plant harvest. The highest unit weight of plants was obtained with the application of ammonium sulfate in the form of a solution with a lower calcium carbonate dose, compared to the remaining combinations. The examined spinach beet plants were distinguished by high contents of dry matter, protein, total nitrogen, potassium, calcium and magnesium The chemical composition of leaves was significantly differentiated, depending on the examined factors. The contents of nitrates in the leaf dry matter ranged from 0.26 to 0.45%, depending on the kind of nitrogen fertilizer and manner of its application. The applied nitrogen fertilization to a small extent influenced the concentration of nitrates in beet leaves. More nitrates were contained in plants fed by a higher dose of calcium carbonate, compared to the plants which were given a lower dose of CaCO₃. The highest content of vitamin C and the lowest share of nitrates in leaf dry matter were obtained with the application of urea in the form of deposit with a lower dose of calcium carbonate.

Yucca elephantipes is an important commercial ornamental pot plant, excellent for growing in flats, patios or winter gardens. Traditional vegetative propagation of the most decorative yuccas is complicated due to a very low rate of propagation, so in vitro culture is an alternative method for commercial propagation of these plants. The influence of BA (0.4, 2.2, 4.4, 11.1, 22.2 µM) and TDZ (0.5, 2.3, 4.5, 11.4, 22.7 µM) on shoot multiplication of Yucca elephantipes Regel on Murashige and Skoog (MS) medium was studied. Explants cultured on medium without growth substances were used as a control. The two types of explants used in the experiment: shoot tips and nodal segments of shoots, were obtained from aseptically grown shoot clusters. When comparing regeneration capability of 2 types of Yucca elephantipes explants, it was found that more newly formed shoots and roots were obtained from nodes. The highest formation of shoots was obtained from nodes on MS medium supplemented with 4.5 µM TDZ or 11.1 and 22.2 µM BA (6.5, 6.0, 5.8, respectively). The shoots regenerated from nodes showed best elongation. On the control medium and on the media with the lowest level of BA or TDZ, their average length was 31.0–37.8 mm. The growth regulator-free medium and the media with a low level of BA were the most effective in inducing roots.

Cucumber is one of the most popular vegetables in Poland. This vegetable species is characterised by high requirements in terms of soil temperature and moisture. The utilization of polyethylene mulch in combination with drip irrigation has played a major role in the increases in production of cucumber. The benefits associated with the use of this cultivation method include earlier and higher yields, reduced soil evaporation, reduced weed populations, reduced fertilizer leaching, greater water use efficiency, reduced soil compaction, control of certain pests, and cleaner harvested product. In years 2002, 2003 and 2005 experiments were conducted to study the impact of soil mulching with black polyethylene on Akord F1 cucumber yields. Plants were cultivated on sandy loam soil using irrigation and fertigation applied with the assistance of drip lines. No significant differences were observed in levels of total and marketable yields of fruits as well as in dry matter and total carbohydrate contents in fruits obtained from plants cultivated in mulched and unmulched soils. Irrigation efficiency, on the soil mulched with black polyethylene was higher than on the soil without mulching.