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The study assessed the effect of cumulative tropospheric ozone on the morphology of an ozone-sensitive (Bel W3) and an ozone-resistant (Bel B) tobacco cultivar, and two petunia cultivars (Mirage, White Cascade). The plants were exposed at two sites differing in tropospheric ozone level for two months during the 2008 growing season. Similar sets of plants were cultivated in control conditions. Morphological parameters of the plants were measured every week during the experiment. The correlation between the recorded results and the cumulative concentrations of tropospheric ozone measured at the two exposure sites was estimated. The ozone-sensitive tobacco cultivar showed increased visible damage after four weeks of the experiment, although ozone was relatively low during the preceding weeks, possibly confirming the cumulative effect of ozone on the plant response. The ozone-resistant tobacco cultivar showed higher mean plant growth and leaf growth than the ozone-sensitive one throughout the experimental period, but at the exposure sites the ozone-sensitive cultivar showed plant growth similar to or higher than the controls, especially at the forest site where ozone concentrations were higher. This suggests a plant defense against reduction of leaf assimilation area (i.e., against leaf necrosis). Petunia cv. Mirage showed lower growth at the control site and had fewer flowers than White Cascade at all sites. White Cascade had more flowers than Mirage in the last week of the experiment at the forest site where tropospheric ozone was higher. Its mean growth was higher at the forest site than at the other exposure site.
Ozone-sensitive and -resistant tobacco plants and an ozone-sensitive bean were employed in this experiment. Plants were exposed at two different sites varying in ozone level, within Poznań city and in a remote forestry area. Net photosynthetic rate (PN), stomatal conductance (gs ) and intercellular CO₂ concentration (Ci ) were measured every 7th day until the 28th day of the experiment. The ozone concentrations were higher at the forest site (called here the high ozone site) than in the city (low ozone site). Mean hour ozone concentrations at forest site varied between 34.2–45.5 ppb and 30.2–39.2 ppb, while cumulative ozone concentrations (AOT 40) were 2032 ppb h⁻¹ and 611, respectively. The aim of the study was to compare the results of exposed ozone-sensitive and resistant test plants according to the potential effect of tropospheric ozone on natural vegetation. The experiment revealed the variability between exposure sites and plant species, as well as changes of photosynthetic parameters during the whole experimental season. Common bean assimilation parameters revealed the best correlation with the tropospheric ozone level. Tobacco test plants – ozone-sensitive and -resistant – varied in response to stress factors. There were no statistical differences between exposure sites and plant response. However, both ozone-sensitive and -resistant tobacco plants revealed lower levels of PN at the low ozone site, while ozone-sensitive bean revealed the opposite relation. Moreover, plants revealed gas exchange relations which were not previously observed in fumigation experiments (such as small differences in Ci levels of tobacco plant in the first three weeks). This might be a result of relatively low levels of tropospheric ozone during the experimental period. Hence, it is suggested to continue ambient air investigations to confirm or reject the results of this experiment.
The aim of the present study was to examine physiological and morphological characteristics of Spartina pectinata ‘Auremarginata’ in response to various soil salinity conditions. Investigating the plant’s response and time-point of potential adjustment to salinity stress will help determine the suitability of the species for growing in the roadsides. The effect of various levels of salinity on S. pectinata ‘Aureomarginata’ was examined. The NaCl was applied at five different levels (g·dm–3): 0 (control), 15, 30, 45, 60. The plant response was analysed after 14, 28, 42 and 56 days of the experiment. The highest concentration showed the strongest negative effects, which were indicated by a decrease in net photosynthesis rate (PN), stomatal conductance (gs), transpiration rate (E), specific leaf area (SLA), relative water content (RWC) and the number of shoots, number of young shoots and length of mature shoots. Plants have even some types of adjustment to stress conditions, at medium levels. This was especially valid for PN and gs after 28 days of the experiment. Principal component analysis revealed negative relationship of salinity level with PN, gs, E, RWC, SLA, number of young shoots and number of shoots, whereas a positive relationship was recorded with CMS, Ci, number of young leaves and leaf chlorophyll content (SPAD).
Nine grapevine cultivars varying in fruit yield were tested for photosynthetic activity, chlorophyll content and leaf area during the 2010 growing season. Relationships between these parameters and berry yield were examined. Investigations revealed differences between the photosynthetic activity and other parameters of the selected grapevine cultivars. A high net photosynthetic rate was usually associated with high efficiency of CO2 during photosynthesis, due to high stomatal conductance. However, a high net photosynthetic rate was not always related to high leaf area and berry yield. Specific leaf area did not vary between cultivars. Fruit production in some cultivars was positively related to photosynthetic activity, while in other cases plants focused on fruit development, hence low values of photosynthesis and/or low leaf area were recorded.
Eight-week-old tobacco (Nicotiana tabacum L.) Bel W3 (ozone sensitive) and Bel B (ozone resistant) cultivars were exposed to ozone for two weeks at two sites with differing tropospheric ozone levels in five independent series from May 27 to July 25, 2004. After each exposition, the degree of ozone-caused visible leaf damage and the activity of APX, GuPX, and SOD were examined. Visible leaf damage was observed only in the sensitive cultivar; the resistant one did not exhibit any external symptoms. Three-way ANOVA revealed that the activity of all enzymes varied by exposure site, series and cultivar effects. Significant correlations between GuPX activity in the two cultivars and with the degree of leaf damage to the sensitive cultivar were found. This indicates that GuPX activity in the sensitive as well as in the resistant cultivars track changes in tropospheric ozone levels. The positive correlation between ozone level and APX activity in the resistant cv. Bel B, which did not reveal visible symptoms, indicates that this enzyme may contribute to detoxication of H2O2 and alleviation of oxidative damage caused by O3
Two inoculums: Effective Microorganisms (EM) specimen available on the market and microbiological BAF1 inoculum, were applied in the experiment. The plants were cultivated in the growth chamber equipped with shelves with fluorescent or LED lamps. The highest number of inflorescences was under the influence of white color of light emitted by fluorescent lamps and blue color of light emitted by LED lamps, especially after application of BAF1 inoculum. Irrespective of microbiological inoculum, no significant effect of the color of light and type of lamps on such traits as height of leaves layer, number of leaves, greening index of leaves (SPAD) and length of inflorescences, was found. The white color light emitted by fluorescent lamps stimulated actinobacteria multiplication, especially after EM application. Regardless of the inoculum application, it was the blue color light emitted by LED lamps that stimulated the multiplication of moldy fungi. After the use of fluorescent lamps, the increase in dehydrogenase activity was observed, especially after the application of BAF1 inoculum. The activity of acid phosphatase was stimulated by blue and white+blue light emitted by LED lamps. The increase in the activity of urease was observed under fluorescent lamps emitting the green, blue and white color of light, after the application of EM.
The aim of our study was to determine the dynamics of development of select groups of microorganisms and the activity of dehydrogenases in a substrate containing a microbiological inoculum (BAF1) intended to improve scarlet sage growth and flowering. The material used in the investigations was peat substrate of 5.5-6.0 pH into which plants were planted and then inoculated with different doses of the BAF1 biopreparation (1:10, 1:50, 1:100). Samples of the substrate were collected during the following three phases: seedling planting, vegetative growth, and flowering. The following parameters were determined: developmental dynamics of total bacteria number, actinomycetes, molds (Koch plate method), and dehydrogenases activity (spectrophotometric method). Moreover, plant morphological parameters such as plant height, shoot number and length, number of buds and inflorescences, as well as content of chlorophyll a+b, a, and b, and leaf greenness index (SPAD) were also measured. The application of the BAF1 inoculant into the peat substrate contributed to increased number of heterotrophic bacteria, actinomycetes, molds, and dehydrogenases activity. The number of the studied microorganisms were stimulated most significantly by the applied foliar application of the biopreparation at 1:10 concentration, while their metabolic activity also was stimulated by the foliar application of the experimental inoculum applied at a concentration of 1:50. The applied BAF inoculum failed to exert a significant effect on the number and greenness index of leaves or on leaf blade width and length. However, irrespective of the dose and method of application of the inoculum, it improved the degree of coloring of inflorescence buds and affected the length of inflorescences (in particular, the foliar and soil application of 1:50 concentration) and increased the chlorophyll content in plants (especially the soil application with the biopreparation at 1:50 concentration, as well as foliar application at 1:100 concentration).
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