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Water and nitrogen managements are both very important to increase crop yield. An experiment was carried out in split plot design to study the effects of urea types (normal urea and coated urea) and irrigation on soil and fertilizer nitrogen use in maize (Zea mays L.) field in 2006 and 2007. Irrigation was used as main plot, and urea types were used as split-plot. Two irrigation levels, no irrigation in the whole growth duration and 85 mm irrigation at the blister stage, were designed. There were five nitrogen treatments, which were no nitrogen used as control (N0), normal urea 75 kg N/ha (N1), normal urea 150 kg N/ha (N2), coated urea 75 kg N/ha (C1) and coated urea 150 kg N/ha (C2). The results showed that, at the same level of irrigation and nitrogen, the soil nitrogen contents of the treatments with coated urea (CU) applied were higher in 0~40 cm soil layers, but lower in deeper soil layers, than those with normal urea (NU) applied. Irrigation increased the nitrate losing, but the nitrate loss of CU was lower than those of NU. Using CU with irrigation could increase the nitrogen uptake by maize, and more nitrogen was transfered to grain. At the same nitrogen level, CU had higher N recovery efficiency but lower soil N dependent rate than NU. When applied with CU, the nitrogen release rate was lower and the nitrogen was quickly absorbed by maize, which reduced the risk of nitrogen loss and increased the use efficiency of soil and fertilizer nitrogen. These results suggest that coated urea combined with deficit irrigation should be applied for high yield and nitrogen use efficiency of maize on the North China Plain.

The aim of this work was to estimate the changes in contents of different sulfur (S) fractions in soils under conditions of lowering inputs of S from emissions together with the influence of application of manure and mineral fertilizers. Soil samples from long-term field experiments were used for this purpose. The samples were taken from 10 sites from precise long-term field experiments with different soil-climatic conditions in the Czech Republic. The samples were analyzed using the following fractionation: (i) water soluble S (H₂O extracts), (ii) sorbed S (0.032M NaH₂PO₄ extracts) and (iii) S occluded with carbonates (1M HCl extract). Furthermore, the concentration of total S (S_tot) and organic S (S_org) was determined. Soil samples were taken in the years 1981 and 2007. During 26 years a decrease of S_tot by about 3-8%, water soluble S by 65-68% and sorbed S by 39-44% were observed in the topsoil of the evaluated soils. Furthermore, a low increase in the content of organic S was observed. The estimated ratio of S_org reached 78.7-80.9% from S_tot in the year 1981 and 87.7-89.8% in 2007. Farmyard manure (40 t/ha) applied every 4 years did not have a significant influence on S fractions and S_tot contents in soils; intensive S fertilizing increased S_tot and mobile S forms contents in soils. Very close correlations were obtained especially between S_tot and water soluble S and organic S.

The aim of the study was to collect seeds of wild oat from the fields where, in spite of the applied herbicides, the weed is very poorly controlled, and to determine under greenhouse conditions if any resistant biotypes are present. In the years 2008-2011, 34 samples of wild oat were collected from fields where the weed was poorly controlled. The biotypes were analyzed in greenhouse experiments to determine if they are resistant to herbicides. Among five resistant biotypes three of them (R3, R4 and R5) were resistant only to iodosulfuron and mesosulfuron, and biotype R2 - only to propoxycarbazone-sodium. Biotype R1 exhibited multiple resistance to iodosulfuron + mesosulfuron and pinoxaden. The use of sulfometuron proves that the mechanism of resistance of two biotypes of wild oat (R1 and R4) to acetolactate synthase inhibitors is associated with target-site mutation. The curve of biotypes R3 and R5 controlled with iodosulfuron + mesosulfuron shows a relatively low resistance index and control of those biotypes with sulfometuron indicates a metabolic resistance.

We aimed to evaluate the extractability of different extractants for zinc (Zn) and copper (Cu) in soils of long-term field experiments covering different agro-ecological zones of India. The relationships between the amounts of Zn and Cu extracted by Mehlich 3, 0.1 mol/L HCl and AB-DTPA (ammonium bicarbonate-diethylenetriaminepentaacetic acid) with those extracted by DTPA, the conventional extraction method widely used in soil testing laboratories in India, were elucidated. The treatments of the long-term experiments included control (no fertilizer), 100% NPK, 50%NPK + 50% N through FYM (farm yard manure) and a fallow soil. Some important physico-chemical properties of soil like pH, organic carbon, textural class, CaCO₃ content, etc. were analyzed. The NPK + FYM treatment was found to be the most effective treatment in terms of increased content of Zn and Cu in soils. The results showed that the amount of Zn and Cu extracted by Mehlich 3 were significantly correlated with that extracted by 0.1 mol/L HCl (r = 0.970** for Zn and r = 0.914** for Cu). Accordingly, Mehlich 3 and 0.1 mol/L HCl could be used effectively for estimating Zn and Cu availability in soils of India. However, Mehlich 3 was superior to all the other extractants used for the study.

The upper values of the extractability of trace elements (As, Be, Cd, Co, Cr, Cu, Ni, Pb and Zn) in 2 mol/L HNO₃ and 0.025 mol/L ethylenediaminetetraacetic acid (EDTA) (compared with their pseudototal content in aqua regia) for determination of prevailing anthropogenic and geogenic soil load were proposed and compared with the results of the other 30 Fluvisol samples collected from the Labe fluvial zone. The increased geogenic load of Fluvisols was confirmed in the case of Be and As in some localities where low extractability with increased pseudototal contents were detected as opposed to the other elements when their increased pseudototal contents were followed by their increased extractability. The maps of probability of increased geogenic soil load in the area of the Czech Republic based on the comparison of geological substrates and trace element load were constructed. The combination of proposed elements extractability values for geogenic load together with developed maps is a suitable tool for the definition of prevailing Fluvisol or sediment load on some localities in the whole area of the Czech Republic. The results can be also a useful tool in the decision making processes regarding dredged sediment application on agricultural soil (support tool for legislative norms, Direction No. 257/2009 Sb.).

In the past few years in Europe grass seed production declines. This tendency is especially pronounced in meadow fescue. Seed shedding and therefore yield losses are the problem in seed production. This can be reduced if seed of higher moisture contents is harvested. The impacts of drying temperatures of 70, 60, 50, 40 and 22°C on changes in dormancy and germination of seed harvested with moisture contents of 45, 35 and 25% were observed in the present study. The analysis was done immediately after seed drying, then three months later and eight months later. Seeds with the moisture content of 45% that were dried at 70°C were not dormant at all after harvest, but seeds were damaged, which resulted in reduced germination. Drying temperatures of 40°C and 50°C resulted in maximum germination of seed harvested with 45% moisture after three months. After eight months the best germination of all seeds was obtained at 22°C and 40°C. The seed ageing test confirmed faster deterioration of seeds harvested with higher moisture contents. Seed harvested with 25% moisture and dried at 22°C is the most suitable seed for longer storage.

Subsoil compaction can result in unfavourable soil physical conditions and hinder the root growth of maize. The effects of deep tillage and conventional tillage on soil physical properties and root growth of maize were studied during 2010-2011 at two sites (loam at Hebi and clay at Luohe) in central China. The results showed that soil penetration resistance, bulk density, water content and root length density were significantly affected by tillage, soil depth and year. Deep tillage had lower penetration resistance and lower soil bulk density, but higher soil water content than conventional tillage across years and depths. Averaged over the whole soil profile, deep tillage not only significantly decreased penetration resistance and soil bulk density, but significantly increased soil water content and root length density on loam, while deep tillage only significantly increased the root length density on clay. We conclude that deep tillage on the loam is more suitable for the root growth of summer maize.

This study aims to explore the optimum nitrogen (N) application method by analyzing effects of variable N application stages and ratios on the N absorption and translocation of high-yield summer maize (DH661). The study included field experiments and ¹⁵N isotopic dilutions for pot experiments. Results showed that the yield was not increased in a one-off N application at the jointing stage. The uptake of fertilizer-derived N in the grain increased with the increasing of N applied times. Compared to a single or double application, total N uptake (N_up) and biomass increased significantly by supplying N at the six-leaf stage (V6), ten-leaf stage (V10) and 10 days after anthesis in ratios of 3:5:2 and 2:4:4. The fertilizer-derived recovery rates were 67.5% and 78.1%, respectively. The uptake and utilization of fertilizer-derived N was enhanced by increasing the recovery rate of N supplied after anthesis, and reducing the absorption of soil-derived N. Therefore, the 2:4:4 application ratios was the optimal N application method.

Composting has been considerably recognized as a viable management method for solid organic wastes aimed at recycling of its end-product as a potting substrate for ornamental plants. Pelargonium and Salvia as salt-sensitive plants were grown in the mixture of compost (75, 50, 25% by volume) and additives (Hygromull, Cocofiber and SPS-standard soil type 73 with 70% peat and 30% clay). Since plants may suffer from a high salt content, thus in a further experiment compost was added as a partial substitute for peat. The results of the first pot experiment reveal that the large percentage of compost in the substrate had negative effects on plant growth and nutrient uptake (N, P, K and Na). Both yield formation and nutrient uptake significantly increased and almost gained levels of those in the control in the second pot experiment when plants were grown in peat-based substrates. Especially, the growth of Salvia was significantly improved. Consequently, the compost-based media (> 50% volume of compost) cannot be recommended for salt sensitive ornamental plants, while less than 25% of compost incorporated into peat creates peat-based substrates which reasonably enhanced growth of Pelargonium and Salvia.

The paper presents the contents of phosphorus and potassium available in soil, soil sorption properties against the activity of alkaline and acid phosphatase. The fertilisation applied involved P, K, Mg, Ca and S: (P K Mg Ca S), (K Mg Ca S), (P Mg Ca S), (P K Ca S), (P K Mg S), (P K Mg Ca) as well as nitrogen fertilisation at the following rates: 0, 50, 100, 150, 200, 250 kg N/ha. The application of high nitrogen rates with no liming applied resulted in an unfavourable increase in hydrolytic acidity and a decrease in the total bases, cation exchange capacity as well as the sorption complex saturation with bases. According to the criteria provided in PN-R-04023, the soil investigated can be classified as the 3^rd class with an average available phosphorus (P_E-R). The analysis of Luvisol salinity demonstrated that the unbalanced mineral fertilisation applied did not trigger any chemical degradation. Significant values of the coefficients of correlation were recorded between the activity of alkaline and acid phosphatase and the parameters investigated (hydrolytic acidity, total exchangeable, base stauration, P_E-R). The calculated enzymatic index of soil pH (AlP/AcP) ranged from 0.11 to 0.72.

Low application of fertilizer potassium (K) in intensive agriculture leads to a gradual decrease and, afterwards, to a steady state of soil K determined by tests which are based on soil exchangeable K (K_exch) extraction. In this situation, non-exchangeable K (K_non-exch) is being released and therefore real plant availability does not necessarily correspond to soil test K. This incoherency was investigated in 14 agricultural soils with low K as determined by the Mehlich 3 method. Plant-available K released by exhaustive cropping of perennial ryegrass and K determined by the Neubauer seedling test were compared with 8 soil K extraction methods, with the total K content and with the relative content of soil K-bearing minerals. K determined by the ryegrass test (314 mg/kg on average) was more than 3-times higher than K based on K_exch extraction methods, but was from 2 to 3 times lower than K determined by K_non-exch extracting methods. The relative content of mixed-layer phyllosilicates was significantly related to K extracted by soil tests. The relative content of orthoclase correlated only with total K and mica-group minerals with none of the extractions. The best prediction of plant-available K in investigated soils was obtained with sodium tetraphenylboron and StepK methods.

The yield forming response of maize cultivar to zinc (Zn) application depends on its timing. This hypothesis was validated in 2007, 2008, 2009 and 2010 growing seasons. The zinc treatments as the first factor were: NPK; NPK + Zn applied before sowing; NPK + Zn applied to maize at the stage of 4^th leaf. The second factor was the maize type: stay-green (modern cultivars) - Paroli, Veritis, Anamur; classical (old cultivars) - Inagua, Kirola. The grain yield of modern cultivars responded the best to zinc applied before sowing, whereas the old ones, when applied to foliage. The yield of the stay-green maize depended upon the number of kernels per row, whereas the classical one on all yield structural components. The zinc management in the modern cultivars should be oriented towards maximization of the number of kernels per row, whereas in the old one on its optimization with the simultaneous kernel weight increase. The positive impact of zinc application before sowing on dry matter translocation from vegetative tissues to growing kernels underlines its practical usefulness, especially in areas with frequent water shortage during maize growth.

A new, effective and economical method to extract ardicrenin from Ardisia crenata Sims collected in the Wolong natural reserve, Sichuan, China, is established. Ardisia crenata Sims powder is counter-current extracted with 80% methanol reflux, decompressively enriched and centrifuged to defat. Supernatant is applied to macroporous resin column (AB-8) with 80% methanol, ardicrenin is isolated by silica gel chromatography with dichlormethane-acetoacetate-methanol (4:1.5:1) washing, and recrystallized in methanol. The final product which proved to be ardicrenin by analytic procedure including Furier transform infrared (FTIR) and ultraviolet spectrum (UV), mass spectroscopy (MS), nuclear magnetic resonance (NMR) and high performance liquid chromatography (HPLC) is white amorphous powder with yield of 1.59 ± 0.02%.

A reduction in the water available to plants will lend increasing importance to the dynamics of water uptake and to the water use efficiency (WUE) of cereals. The effect of drought on the water use efficiency of winter cereals was investigated in a greenhouse experiment in the Centre for Agricultural Research. The effect of water deficiency on the water use properties was studied by measuring changes in the grain weight, thousand-kernel weight and aboveground biomass. The water use efficiency of wheat varieties generally ranged from 1.5-2.3 kg/m³ and 1.06-2.0 kg/m³ in the case of optimum and limited water supplies, respectively, while these figures were 1.4 kg/m³ and 0.8 kg/m³ for winter barley and 0.8 kg/m³ and 0.5 kg/m³ for winter oat. Investigation on the relationship between harvest index (HI) and WUE was found that the harvest index is only one indicator of drought tolerance; but the stability of HI under non-optimum environmental conditions also needs to be determined.

The research results have shown that the enzyme pH index (0.49-0.83) confirmed the neutral or alkaline nature of the soils. Neither the changes in the content of available phosphorus nor in the activity of dehydrogenases, catalase, alkaline and acid phosphatase in soil were due to the factors triggering soil salinity; they were a result of the naturally high content of carbon of organic compounds, which was statistically verified with the analysis of correlation between the parameters. There were recorded highly significant values of the coefficients of correlation between the content of available phosphorus in soil and the activity of alkaline (r = 0.96; P < 0.05) and acid phosphatase (r = 0.91; P < 0.05) as well as dehydrogenase (r = 0.90; P < 0.05). To sum up, one can state that Mollic Gleysols in Inowrocław are the soils undergoing seasonal salinity; however, a high content of ions responsible for salinity is balanced with a high content of organic carbon, humus, phosphorus and calcium directly affecting the fertility of the soils analyzed. The activity of the enzymes depended on the natural content of carbon of organic compounds and not on the factors affecting the soil salinity, which points to the potential of such tests for soil environment monitoring.

The aim of the study was to determine plant needs with regard to sulphur fertilization based on the assessments of sulphur in the soil profile carried out in the early spring. The study was founded on the continuous fertilization experiment established in 1985 at the Experimental Station of the Faculty of Agriculture and Biology, Warsaw University of Life Sciences-SGGW, which is located in Skierniewice. Soil samples were collected in the years 2009-2011 in the early spring (February/March) at low soil temperatures. The samples were taken at three soil depths: 0-30, 30-60, 60-90 cm. The content of sulfate sulphur was assessed in fresh soil samples after extraction in 0.01 mol/L CaCl₂. The plants cultivated during the study were spring barley and yellow lupine. The amount of sulphur in soil profile was too small and not sufficient to fulfill yellow lupine nutritional needs, thus could be a limiting factor for successful yield production. Regardless the fertilizer treatment, the amount of sulfate sulphur found in 0-60 cm soil layer fully covered nutritional needs of spring barley.

This study investigated microbial biomass-N (MB-N) and N-mineralization in soils of four different vegetation systems including forest (sal), mixed forest, savanna and cropland ecosystems in the Vindhyan region, India. A change was noted in the above region due to physiographic differences and anthropogenic disturbances. Annually the soil moisture (SM) content across the different study sites ranged from 7.5 to 24.3% being maximum in forest sites compared to savanna and cropland sites. The NH₄⁺-N, NO ^-₃ -N and MB-N concentrations varied from 4.3 to 10.2 μg/g, 1.1 to 5.8 μg/g and 21.3 to 90.2 μg/g dry soil, respectively, with minimum values in the wet and maximum values in the dry season. The trend of seasonal variation in net N-mineralization was similar to that of moisture content but counter to the concentrations of inorganic-N and MB-N. The net N-mineralization rates at different investigated sites ranged from 4.5 to 37.6 μg/g month. Cultivation reduced the N-mineralization and MB-N by 58.5% and 63.5%, respectively. Experiments showed that the percentage contribution of MB-N to total-N was 8.01 to 19.15%. MB-N was positively correlated with the inorganic-N (n = 180,r.80,P < 0.001) but negatively with soil moisture (n = 180, r = 0.79, P < 0.001) and net N-mineralization rates (n = 180, r = 0.92, P < 0.0001). The higher N-mineralization and MB-N in the soil of forest ecosystem was reported compared to savanna and cropland and the order of soil MB-N levels and net N-mineralization followed the sequence: forest (sal) > mixed forest > savanna > cropland.

A field experiment was conducted in 2008-2010 at the Experimental Station of the Faculty of Agricultural Sciences in Zamość (50°42'N, 23°16'E), University of Life Sciences in Lublin. The aim of the study was to assess the impact of cropping method and weed control methods on the content of Cu, Zn, Fe and Mn in maize and on their uptake. Two cropping methods were studied - sole cropping and strip cropping (common bean, dent maize and spring barley in adjacent strips) and two weed control methods - mechanical and chemical. Strip cropping reduced Mn content in maize, did not significantly affect Zn content, and increased accumulation of Cu and Fe. The content and uptake of the elements by maize depended on the position of the row in the strip and on the adjacent plant species. Placement next to beans resulted in higher Fe and Zn content, while placement next to barley increased Cu content. The highest Mn content was noted in maize from the centre row. In general, micronutrient uptake by maize was lowest in the middle row. These results indicate that strip cropping can be an effective agricultural practise for plant biofortification.

Soil samples were collected at both jointing and maturing stages of maize and wheat to compare the effects of 4-year no-tillage (NT) and conventional tillage (CT) on seasonal variations of microbial biomass carbon (C), metabolic quotient, and invertase activity in a sandy loam soil in North China. Soil invertase activity significantly increased (P < 0.05) from summer to spring of the next year and then significantly decreased (P < 0.05) from spring to summer. With a delay of about 3 months, soil microbial biomass C and basal respiration altered in a similar pattern, while microbial metabolic quotient changed on the contrary. Compared with CT, the NT practice significantly increased (P < 0.05) soil organic C content, and tended to result in higher soil microbial biomass C and invertase activity, as well as lower soil microbial metabolic quotient, especially at the jointing stage of maize. Our results indicated that NT might play an important role in the improvement of soil microbial efficiency, especially at the maize seedling season.

Chlorine, one of the most abundant elements in nature, undergoes a complex biogeochemical cycle in the environment, involved in the formation of volatile organochlorines (VOCls), which in turn can contribute to environmental problems, contaminate natural ecosystems, and are of public health concern. Several industrial and natural sources of VOCls have already been identified; however, data - particularly on the natural sources - are still scarce. The aim of this study was to investigate the diversity of emission of VOCls from soil and several undergrowth plants collected in temperate spruce forest ecosystem and the effect of salting on the VOCl emission of plants. Undergrowth plants were found to emit chloroform (CHCl₃) in the range of 2.2-201 pmol/day/g dry weight (DW), tetrachloromethane (CCl₄) 0-23.5 pmol/day/g DW, and tetrachloroethene (C₂Cl₄) 0-13.5 pmol/day/g DW; the average emission rates were about 10 times higher than that of soil (2.9-47.2; 0-5.8; 0-3.6 pmol/day/g DW of CHCl₃; CCl₄; C₂Cl₄ emission, respectively). Addition of sodium chloride solution in most cases caused an increase in the emission of CHCl₃ and caused a species specific - effect on the emissions of CCl₄ and C₂Cl₄. The results suggest that the emission of VOCls from spruce forest contribute to the atmospheric input of reactive chlorine; however, on a global scale it is only a minor net source.

The purpose of the studies was to determine the microorganisms communities in the soil under scorzonera cultivation with the cover crops using. The greatest total CFU of bacteria occurred in the soil from the experimental combination where oat ploughed over in spring or autumn was the cover crops. The smallest total CFU of bacteria was obtained after ploughing over the mulch of tansy phacelia. The use of oats and spring vetch had a positive effect on the population of bacteria from the genera of Bacillus and Pseudomonas. The smallest CFU of fungi was obtained from the soil where oat constituted the mulch. Alternaria alternata, Fusarium oxysporum, F. culmorum, Haematonectria haematococca and Thanatephorus cucumeris were most frequently isolated from the soil. The most isolates of the enumerated fungi were obtained from the soil cultivated in a conventional cultivation and after ploughing over the mulch of tansy phacelia plants. The most antagonistic bacteria and fungi occurred in the soil after ploughing over the mulch of oat, while the least in the conventionally cultivated soil.

The objective of the vegetation experiment established in 2008-2011 was to explore the effect of the time and dose of foliar molybdenum (Mo) application on the yield and quality of sunflower. Four treatments were established in the experiment: (1) control - not fertilised with Mo; (2) application of 125 g Mo/ha in the growing stage of 4 developed leaves (V-4); (3) application of 125 g Mo/ha at the beginning of elongation growth (R-1), and (4) split rate of Mo application of 62 g Mo/ha at stage V-4 (4 developed leaves) and 62 g Mo/ha at stage R-1 (terminal bud forms). Foliar application of molybdenum increased the biomass production of sunflower plants and its content in dry matter. A statistically significant effect of molybdenum foliar application on sunflower yields was found. Foliar application of Mo up to a dose of 125 g Mo/ha at the beginning of vegetation (stage V-4) and developmental stage R-1 increased yields of achenes. The relative increase in the oil content after foliar nutrition was not significant and ranged between 1.4% and 2.6%. Oil production increased due to increased yields and stabilised oil content. Foliar application of molybdenum had no effect on the content of oleic acid.

Influence of CULTAN system (controlled uptake long term ammonium nutrition) on the nitrogen uptake by spring barley (Hordeum vulgare L.) was observed at 5-year small-plot field experiments under conditions of the Czech Republic (central Europe). Nitrogen uptake by CULTAN-fertilized plants was more even during vegetation period probably due to delayed term of fertilizer application. Nitrogen concentration in the aboveground biomass at BBCH 51 and in straw had no effect on grain yield. Post-heading nitrogen uptake as well as contribution of nitrogen translocation to total nitrogen in grain did not differ among both nitrogen fertilization treatments. Increase in grain size of spring barley by the CULTAN system can be explained by tendency to lower number of ears per area rather than by prolonged nitrogen uptake from soil. Lower protein content in grain of CULTAN-fertilized spring barley can be caused by increase in grain retained on a 2.5 mm sieve and also decrease in total nitrogen concentration in above-ground biomass at BBCH 51. No significant effect of CULTAN treatment on nitrogen use efficiency and nitrogen uptake efficiency was recorded. Significantly higher nitrogen utilization efficiency at CULTAN treatment could be explained by lower grain protein content compared to conventional treatment.

To investigate the ecological safety of Beauveria bassiana in soil, we evaluated the effects of different concentrations of B. bassiana spores suspensions and acephate on paddy soil microbial flora and enzyme activities in a potted trial. Results showed that B. bassiana can increase the quantity of bacteria and fungi on day 10 and 30, while it showed inhibition on actinomycetes growth on day 10. However, acephate reduced the quantity of bacteria, fungi, and actinomycetes in soil. Investigation of enzyme activities revealed that invertase activity declined during prophase, while urease activity decreased later in B. bassiana treatment groups, and there were no significant changes in alkaline phosphatase or dehydrogenase activity. Acephate showed higher inhibition rates of enzymes. B. bassiana treatment at lower concentrations showed a higher yield. Overall, compared with the acephate, B. bassiana is an effective, environmentally friendly microbial pesticide in this system.

Photosynthesis and transpiration rates in the interval of 30 min before and 30 min after copper fungicide application show an increase from the level of 5.0 to 7.0 µmol CO₂/m²/s and 0.75 to 1.00 mmol H₂0/m²/s. Long-term measurements show that the increase of photosynthesis rate after copper application is temporal and fades away after 10-14 days. No stress response was induced after the application of copper fungicides. Contents of copper in hop cones are up to 500 mg/kg if total amount of applied copper does not exceed 15 kg/ha. Contents of copper on leaves are 2-5 times higher at the same application dose. Application of 5 kg copper per one hectare of vigorous growth of Agnus variety increases content of copper on hop leaves by 1000 mg/kg at least. The same amount of copper increases its content in hop cones by 300 mg/kg at the ripening period. Tight correlation between the amount of copper applied and its content in hops does not exist. Elementary copper from leaves is brought into harvested hops in the form of biological admixtures. Copper content in hop cones shows a decreasing trend, which is given by gradual increase of cones size at the ripening period. Similar trend on hop leaves shows that washing off and dissolving of copper compounds by atmospheric water can participate in this process as well. Common content of copper in untreated hop cones and leaves is up to 20-25 mg/kg.

Chromosomes of potato (Solanum tuberosum) are terminated by telomeres, which are formed by tandemly repeated [TTTAGGG]n oligonucleotide sequence. The total length of blocks of telomeric DNA has been known to vary largely among plant species and their varieties, and also among individual chromosome arms within a single nucleus. To check for such differences in potato varieties, which could be of a possible use in genotyping, we performed pulsed-field gel electrophoretic analysis of terminal restriction fragments in selected potato varieties. We found a typical range of telomere lengths of 20-60 kb in most analysed varieties. In one of analysed varieties (Monalisa), telomeres of wider span (up to 80 kb) have been observed. Most of restriction enzymes (PvuII, HaeIII, TaqI) produced a resulting smeared hybridisation pattern of telomeres. When using BglII, however, a doublet hybridisation band could be observed. This may reflect differences in composition of telomere-associated sequences at different chromosome ends.

The objective of this study was to investigate the capability of radish to extract lead from soils contaminated with lead resulting from air pollution. A randomized block experiment design was performed. The soil was contaminated with PbNO₃ and the treatments consisted of 180 (standard), 250, 350, 450, 800 and 1000 mg/kg lead. After development, plants were harvested and divided into shoots and roots. The lead content of each plant part as well as the soil-lead were measured. The results indicated a non-linear positive relation between the lead concentrations in soil and that accumulated in plant roots and shoots. By increasing the lead concentration in soil, its accumulation in plant tissues was also increased. Most of the extracted lead was accumulated in the roots (208.1 mg/kg) compared to shoots (27.25 mg/kg). Since radish can be seeded up to five times a year, and its yield may reach up to 20 t/ha, it can be used to remediate lead-polluted topsoils (0-10 cm).

Selenium (Se) contamination due to industrial activities has received increasing concerns. Phytoremediation has been suggested to be an efficient and feasible way to remove Se from Se-contaminated environment. Recently, an arsenic (As) hyperaccumulator Pteris vittata L. (Chinese Brake fern) was found to be a Se accumulator. This study was carried out to investigate Se accumulation mechanisms concentrating on antioxidant responses of this plant to six levels of selenite (0, 1, 2, 5, 10, and 20 mg/L). The results showed that Chinese Brake fern can accumulate a large amount of Se without any visible toxic symptoms and significant decreases in its biomass. However, the root took up more Se than the fronds. The highest concentration of Se in the roots and fronds was 1.536 mg/kg and 242 mg/kg, respectively, demonstrating a typical accumulation character to Se. Addition of 2 mg/L Se decreased, but ≥ 5 mg/L Se enhanced the production of malondialdehyde (MDA), suggesting an antioxidant role of low dosages of Se. The enzymes of catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POD) contributed their anti-oxidative functions only under low dosages of Se, as shown by their increased activities at Se levels ≤ 5 mg/L and lowered activities at Se levels > 5 mg/L. The concentration of glutathione (GSH) and enzyme activity of glutathione reductase (GR) were stimulated by ≥ 5 mg/L Se. Superoxide dismutase (SOD) activity was also enhanced by 20 mg/L Se. Our results suggest that SOD, GSH and GR were likely responsible for, but enzymes of POD, APX, and CAT have limited roles in Se accumulation in Chinese Brake fern.

Dissolved organic nitrogen (DON) has high bioavailability and is an important source of soil nutrients. In order to determine the concentrations and the composition of DON in different depths (0-30 cm), and provide a theoretical basis for further deep research into the paddy soil nitrogen supply, experiments based on the lysimeter method were carried out to investigate the effect of fertilization on composition and spatial distribution of DON in paddy soil. Paddy soil was treated under chemical fertilization treatment (CT) and mixed fertilization treatment (MT). With methods of PCR-DGGE and HPLC-MS, the results of the experiments suggested that the samples in 10-20 cm and 20-30 cm under MT had significantly higher bacterial diversity than those under CT except in 0-10 cm. DON had a high percentage (63.1-79.9%) in N_tot of soil solution. The results of the correlation analysis revealed that DON had a significant positive correlation with organic matter content, Shannon-Wiener diversity index (H') and a significant negative correlation with pH. The possible results of HPLC-MS identification of DON from paddy soil solution were that (a) 3-(4-thiazolyl)-l-alanine; (b) 2-phenylbenzimidazole-5-sulfonic acid; (c) 4-(2, 4-difluorophenyl)-3-nitrobenzene carbaldehyde; (d) fendizoic acid.

The effects of irrigation regimes (full irrigation and water-withholding at anthesis) and post-anthesis nitrogen supplies (LN: 0, MN: 20 and HN: 40 kg N/ha) on grain yield and its components in winter wheat were studied, with attention to biomass gain by assimilation and its loss by respiration. Fully-irrigated wheat responded to N fertilization with increased grain number (GN) and decreased grain weight (GW) and achieved similar grain yields (5.2 to 5.5 t/ha) at different N supplies. However, drought-stressed wheat responded to N with higher GN without significant changes in GW, and achieved higher grain yields (2.7 vs. 3.3 t/ha) with HN compared to LN. Net assimilation rates during grain filling (NARg) increased with increasing post-anthesis N fertilization for drought-stressed wheat (NARg: 3.8 and 4.5 g/m/day for LN and HN). Apparent whole-plant respiration (R_A) was not influenced by increased post-anthesis N fertilizer. Thus, in drought-stressed wheat, the total biomass and straw yield at maturity were increased by increasing N supply. These results suggest that high N supply at anthesis satisfied the grains' increased demand for N by increasing post-floral assimilation, and the surplus assimilates not only compensated for the low-N-induced biomass loss by respiration but may also have increased the