Effects of acidic precipitation on the coniferous species of "Kaz" Mountains in "Biga" Peninsula

The effects of acidic precipitation on the main tree species of Kaz Mountains in Biga Peninsula were investigated. Acidic precipitation were first observed with small yellow spots of acid burns on the needles. Then the total chlorophyll content of the Pinus nigra subsp.pallasiana and Abies equi-trojani Aschers sint needles with different age were detected. We have determined a difference in the total chlorophyll content of the needles depending on the species, needle age, altitude, direction and the amount of pollution

Cadmium exposure and changes in some physiological parameters of Quercus robur ssp. robur l. (common oak) and Acer negundo L. (box elder) seedlings

In this research the toxic effects of Cd accumulation on Quercus robur ssp. robur L. (common oak) and Acer negundo L. (box elder) were investigated. Tree seedlings, grown in hydroponic cultures for 4 months, were exposed to different Cd concentrations (3, 9, 27, 81 muM) for 16 days. Cd concentrations in plant organs, total chlorophyll content and peroxidase activity were detected. Cd accumulation in plants increased with increasing concentrations of this heavy metal in the growth medium. Cd was mostly accumulated in the roots, followed by the shoots and leaves, respectively. Decrease in chlorophyll content and fluctuations in peroxidase activity were determined (P <0.05). Among the investigated tree species, Acer was found to be more tolerant to Cd pollution in comparison to Quercus. We suppose that Acer can be planted in the polluted urban areas including urban-parks and roadsides

Roadside pollution of cadmium and lead in Istanbul City (Turkey) and their effects on Picea abies

Evaluation of metal pollution in soils and plants is of environmental importance due to their negative effects. Surface soil and samples of Picea abies (L.) KARST. needles were collected along two contaminated roadsides from urban environment and analysed for metal content. Soil cadmium (Cd) and lead (Pb) concentrations in these sites averaged 0.46 and 209.5 mug g(-1) DW, respectively. In the unwashed 1-year and 2-year old needles the Cd concentrations averaged 0.15 and 0.22, and Pb concentrations averaged 58.6 and 84.9 mug g(-1) DW, respectively. These values lowered in the washed needle samples. Chlorophyll content, peroxidase activity of the needles and annual ring width differences were determined to identify toxic damage of roadside Cd and Pb pollution. Decrease in chlorophyll content and increase in peroxidase activity were detected in the needles. These results were more evident in the 2-year old ones due to the time of exposure. We have not observed a reduction in the annual ring widths related to Cd or Pb, but precipitation may have an effect on them. We suggest that Cd and Pb concentrations determined in this investigation affect chlorophyll biosynthesis negatively and induce the increase in the activity of peroxidase enzyme as a stress response in Picea abies needles

Neuroprotective effects of L-carnitine and vitamin E alone or in combination against ischemia-reperfusion injury in rats.

BACKGROUND: Neurological injury because of transient cerebral ischemia is a potential complication of cardiovascular surgery. In this study, the neuroprotective effects of L-carnitine, vitamin E, and the combination of these agents on ischemia/reperfusion (I/R) injury were determined in a rat model of transient global cerebral I/R. METHODS: Rats were pretreated with L-carnitine (100 mg/kg, i.v.) and vitamin E (50 mg/kg, i. v.), alone or in combination and then subjected to cerebral I/R induced by a four-vessel-occlusion technique for a duration of 15 min followed by 15 min of reperfusion. Malondialdehyde (MDA) levels, superoxide dismutase (SOD) activity, and glutathione (GSH) levels were measured in the cerebral tissues. Histopathological examinations were also carried out under light and electron microscopy. RESULTS: The results showed that I/R elevated MDA levels, which were accompanied by a reduction in SOD activities and GSH levels. Surviving neurons was markedly decreased in CA1 and CA3 subfield of hippocampus in I/R animals. L-carnitine, vitamin E, and their combination restored MDA levels and SOD activities, with a tendency to increase surviving neurons in CA1 and CA3 subfield. Combined treatment of L-carnitine and vitamin E had better GSH levels than individual treatment of these agents. CONCLUSIONS: The results suggest that L-carnitine has a potent neuroprotective effect against cerebral-I/R-induced injury in rat brain that is comparable to that of vitamin E. However, the combined use of L-carnitine and vitamin E does not further protect from neuronal injury, although it provides an increase in GSH levels

Abiotic stress effects on the antioxidative response profile of Albizia julibrissin Durazz. (Fabaceae)

Abiotic stresses (e.g., heavy metals, drought, cold, or combinations) induce oxidative stress with overproduction of reactive oxygen species (ROS). We have investigated the antioxidative responses of Albizia julibrissin Durazz. (silk tree, Fabaceae). Four-month-old plants grown in sand cultures were subjected to various single or sequential treatments involving exposure to cadmium (50-250 mu mol L-1 Cd), lead (1000-5000 mu mol L-1 Pb), chilling at 4 degrees C (CH), or drought (DR), for a period of 7-45 days. Leaf extracts were assayed for glutathione peroxidase (GPX), glutathione-disulfide reductase (GR), catalase (CAT), soluble proline (Pro), ascorbate peroxidase (APX), and guaiacol peroxidase (GUAPX). Cd and Pb accumulation in the leaves was also measured. CAT activity decreased strongly with increasing Pb exposure and after CH. It was also found to be reduced after Cd and DR treatments. GR activity increased highly in nearly all treatments, most strongly at high Cd or Pb, after DR ? CH, and after CH followed by Cd. GUAPX and GPX showed similar trends of increase. APX activity dropped after CH, but increased after low Cd treatment and in CH ? DR sequential stresses. Massive accumulation of soluble Pro occurred after 14-21 days in highly Cd-or Pb-stressed plants. CH or DR acclimation led to some alterations of antioxidative responses, particularly for CAT, GR, and APX. Our data indicate that GSH, GSH-linked redox systems, peroxidases, and Pro are possibly the more important antioxidants under severe stress