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The disturbances in the morphology and anatomical structure of female generative organs were investigated in two species of roadside larch trees Larix decidua Mill., L. decidua subsp. polonica, and L. kaempferi (Lamb.) Carr., within the administrative boundaries of the city of Lublin. The irregularities of female cones appear more often at the juvenile stage of their development. Completely dried cones or cones with partially dried scales were observed on the L. decidua trees growing in a more polluted environment (in comparison with the place of growing of control trees). Among the more developmentally advanced cones, partially dried and completely deformed or bent female generative organs with a disturbed anatomical structure were visible. Peroxidase activity was significant higher in L. decidua subsp. polonica located near the street with heavy traffic. The study can be used as a basis for deeper and more detailed investigations of reproduction of larches in different environments with air pollution in the area of Lublin and its vicinity. Maybe roadside larches and its generative organs can be used as possible biomonitors of air pollution in urban conditions.
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
The combined effects of enhanced UV-B radiation and soil drought on antioxidant enzyme activity were investigated in cucumber leaves. One-month-old cucumber plants (Cucumis sativus cv. Dar) were exposed to UV-B irradiation and water deficit alone or combined. Physiological measurements were made in seedlings kept under stress conditions for nine days and then two more days with stresses withdrawn. Generally a decrease in relative water content and an increase in dry weight content were recorded. The more significant changes were observed under drought than under UV-B radiation and or combined UV-B and drought. Both stresses stimulated antioxidant enzyme activity. Superoxide dismutase activity increased earlier (day 2) than guaiacol peroxidase and glutathione reductase activity (days 5 and 7). Elevation of enzyme activities was higher under drought than under UV-B. Combined UV-B and drought functioned synergistically: one of the stresses reduced the effects caused by simultaneous application of the other.
Previously, a stable cell suspension of cucumber tolerant to 100 µM CdCl2 was obtained (Gzyl & Gwóźdź, 2005, Plant Cell Tissue Organ Cult 80: 59-67). In this study, the relationship between the activity of antioxidant enzymes and cadmium tolerance of cucumber cells was analyzed. A cadmium-sensitive and the cadmium-tolerant cell lines were exposed to 100 µM and 200 µM CdCl2 and the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APOX) and guaiacol peroxidase (POX) were determined. In the sensitive cell line, a decrease of total activity of SOD and POX was observed, whereas the activity of CAT and APOX significantly increased in metal-supplemented medium. By contrast, in the tolerant cells, the total activity of antioxidant enzymes decreased (SOD, CAT) or was maintained at approximately the same level (APOX, POX). Moreover, a different pattern of isoenzyme activity was observed in the tolerant and sensitive cells. These results suggest that an enhanced activity of antioxidant enzymes is not directly involved in the increased tolerance to cadmium of the selected cucumber cell line.
The Salix variegata Franch. seedlings planted in the Three Gorges Reservoir (TGR) water level fluctuation zone (WLFZ) could survive after experiencing several seasons of winter submergence. We investigated the recovery mechanisms of S. variegata seedlings planted at the elevation of 168 m and 172 m in the TGR WLFZ after winter submergence. The results indicated that winter submergence caused some impacts on S. variegata seedlings with increases of hydrogen peroxide (H₂O₂), superoxide anions radical (O₂⁻˙), and malondialdehyde (MDA) levels, and decreases of antioxidant enzymatic systems during recovery stage after winter submergence. However, further analyses of relative water content (RWC), pigment content, proline content, carbohydrate content and several other antioxidant enzymatic activities (catalase (CAT), guaiacol peroxidase (G-POD), and glutathione peroxidase (GSH-POD)) showed that S. variegata seedlings were well recovered after winter submergence. These results indicate that S. variegata possesses strong winter submergence tolerance and adaptation to the specific hydrological environment in the TGR WLFZ. Therefore, S. variegata should be popularized as native tree species during the revegetation in the TGR WLFZ.
Badano akumulację metali ciężkich (Zn, Cd, Pb, Fe, Cu), aktywność peroksydazy guajakolowej (POD E.C. 1.11.1.7) oraz zawartość niebiałkowych grup -SH w liściach Betula pendula Ehrh, Salix cinerea L., Silene vulgaris Moench (Garcke), Tussilago farfara L., rosnących na terenach poprzemysłowych. Zaobserwowano następujący szereg zdolności kumulacji metali przez badane rośliny: Zn > Fe > Pb > Cd > Cu. Metale ciężkie (z wyjątkiem Zn) były bardziej biodostępne na hałdzie w Piekarach niż na terenie pogalmanowym „Warpie”. Wyższe aktywności peroksydazy w liściach badanych roślin, szczególnie u Tussilago farfara stwierdzono na terenie pogalmanowym. Najwyższą zawartość niebiałkowych grup -SH stwierdzono w liściach Salix cinerea pozyskanych na hałdzie w Piekarach.
Radish (Raphanus sativus L.) is commonly grown in urban and suburban areas where the soil may be polluted with heavy metals such as Cu or Pb. In this study, short exposure of radish plantlets to 0.5 mM Cu or Pb in nutrient solution (two days) in growth chamber conditions elicited an antioxidative response, measured in terms of lipid peroxidation, protein and proline accumulation, and peroxidase and catalase activity. Longer exposure to Cu or Pb when radish was grown outdoors for 50 days in pots filled with field soil with different Cu and Pb content also resulted in higher lipid peroxidation and proline accumulation, and altered protein content and enzyme activity. The tested parameters of radish antioxidative responses to heavy metal stress differed depending on plant part (leaf or hypocotyl) and stress intensity (heavy metal content in growth medium, exposure duration). The reported data show that plants grown in soil from sites where this crop could be cultivated do show an oxidative stress response similar but not identical to that seen under laboratory treatment with heavy metals.
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