We present here the effects of ambient ozone (O3)-induced decline in carbon availability, accelerated foliar senescence, and a decrease in aboveground biomass accumulation in the Aleppo pine (Pinus halepensis Mill.). Aleppo pine seedlings were continuously exposed in open-top chambers for 39 months to three different types of O3 treatments, which are as follows: charcoal-filtered air, nonfiltered air (NFA), and nonfiltered air supplemented with 40 ppb O3 (NFA+). Stable carbon isotope discrimination (Δ) and derived time-integrated ci/ca ratios were reduced after an accumulated ozone exposure over a threshold of 40 ppb (AOT40) value from April to September of around 20,000 ppb·h. An AOT40 of above 67,000 ppb·h induced reductions in ribulose-1, 5-biphosphate carboxylase/oxygenase activity, aboveground C and needle N and K concentrations, the C/N ratio, Ca concentrations in twigs under 3 mm, and the aerial biomass, as well as increases in needle P concentrations and phosphoenolpyruvate carboxylase (PEPC) activity and the N and K concentrations in twigs under 3 mm. Macronutrients losses, the limitations placed on carbon uptake, and increases in catabolic processes may be the causes of carbon gain diminution in leaves which was reflected as a reduction in aboveground biomass at tree level. Stimulation of PEPC activity, the consequent decreased Δ, and compensation processes in nutrient distribution may increase O3 tolerance and might be interpreted as part of Aleppo pine acclimation response to O3.

Water quality analyses were performed on littoral water samples, collected on Lake Ohrid in 2002 (January, February, June, July, August and September). Several microbiological parameters were compared. The number of Escherichia coli, the number of organotrophic bacteria and the phosphatase activity index were measured. Samples were collected along the shore of Lake Ohrid, i.e. at the village of Pestani, at Hotel Metropol, in Ohrid Bay and at the lake inflow of River Velgoska. The results of the study show that the different parameters are not compatible in terms of water quality characterization. The differences found are discussed below.

The basic purpose of Gruza accumulation is to supply the town of Kragujevac and its vinicity with drinking water. The accumulation occupies large area, comparing with its relatively shallow water and low water mass, which is essential for water eutrophication. The aim of this research is to determine water quality, through index of phosphatase activity at five locations in one year period. According to the results obtained for index of phosphatase activity, water of Gruza lake belongs to 3rd A category. The maximum obtained value (19.60 micromol/s/cubic dm) was determined in the shallow part, at mouth of the river Gruza in July, 2000, and the minimum one (0.39 micromol/s/cubic dm) in the deepest part of accumulation, at location Brana in March, 2001.

The activities acid, neutral and alkaline phosphatases, as well as total phosphatases activities were estimated in the water of the Lake Ohrid tributaries Sateska, Koselska, Velgoska and Cherava. The same analyses were performed in the littoral zones where the tribitaries enter Lake Ohrid. The study covers the period from September 2000 to October 2001. The obtained results show that different types of phosphatase effect different extracellular activities, an observation which is probably the result of differences in the location within the cells and the way of intracellular synthesis.

We present here the effects of ambient ozone (O3)-induced decline in carbon availability, accelerated foliar senescence, and a decrease in aboveground biomass accumulation in the Aleppo pine (Pinus halepensis Mill.). Aleppo pine seedlings were continuously exposed in open-top chambers for 39 months to three different types of O3 treatments, which are as follows: charcoal-filtered air, nonfiltered air (NFA), and nonfiltered air supplemented with 40 ppb O3 (NFA+). Stable carbon isotope discrimination (Δ) and derived time-integrated ci/ca ratios were reduced after an accumulated ozone exposure over a threshold of 40 ppb (AOT40) value from April to September of around 20,000 ppb·h. An AOT40 of above 67,000 ppb·h induced reductions in ribulose-1, 5-biphosphate carboxylase/oxygenase activity, aboveground C and needle N and K concentrations, the C/N ratio, Ca concentrations in twigs under 3 mm, and the aerial biomass, as well as increases in needle P concentrations and phosphoenolpyruvate carboxylase (PEPC) activity and the N and K concentrations in twigs under 3 mm. Macronutrients losses, the limitations placed on carbon uptake, and increases in catabolic processes may be the causes of carbon gain diminution in leaves which was reflected as a reduction in aboveground biomass at tree level. Stimulation of PEPC activity, the consequent decreased Δ, and compensation processes in nutrient distribution may increase O3 tolerance and might be interpreted as part of Aleppo pine acclimation response to O3.

In recent works enzymatic phosphatase activity state as a new potential good indicator for water saprobity and trophic state in water. On water reservoir 'Grliste' reinstated monitoring on the base physico-chemical, microbiological and biological analysis from beginning works water factory 1990 but, from 1998 use of this new biochemical method in monitoring as reliable additional indicator in fast preliminary water quality and the ecophysiological state of water. According to the results obtained for index of phosphatase activity (IFA) (Matavulj, 1986) water of 'Grliste' water accumulation belongs to category 3-A (polluted water).