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The study aimed to clarify some biochemical properties, important for the phytopharmaceutical use of yarrow from the A. millefolium agg.. The study comprised 41 populations from Slovenia. The most abundant taxa were included: Achillea millefolium L., A. roseoalba Ehrend., A. collina (Wirtg.) Becker ex Rchb., A. distans Waldst. & Kit. ex Willd., A. pannonica Scheele, A. pratensis Saukel & R.Länger and A. nobilis L. Assessment of essential oil content with the steam distillation method showed no significant difference between taxa. Essential oil content was the lowest in A. collina (6.50 ml kg-1 of dry matter), followed by A. pannonica (7.75 ml kg-1), A. distans (8.50 ml kg-1), A. nobilis (9.40 ml kg-1), A. pratensis (9.65 ml kg-1), A. nobilis × A. millefolium (12.25 ml kg-1), A. roseoalba (12.75 ml kg-1) and A. millefolium (13.50 ml kg-1). The content of azulenes was determined by photometrical measurement of chamazulene in essential oil extracts. Chamazulene was only present in the diploid taxon and one tetraploid taxon, i.e., A. roseoalba (0.16 % of dry plant mass) and A. collina (0.05 %). The differences in antioxidative capacity of extracts from different taxa were not statistically significant, so we can assume that specific antioxidative capacity is not bound to a specific taxon or ploidy level.

Grassland habitats were studied on twenty farms on the area of the Radlje ob Dravi administration unit, in the transect from Kozjak to Pohorje at different altitudes. The aim of the study was to investigate how environmental and socio-economic parameters influence the diversity of plant species and, consequently, the conservation of grassland on acid soils, which are rare in Slovenia and are therefore more protected. The socioeconomic structure of farms was studied on the basis of an inquiry carried out on farms. Part-time farms prevail; the average age of farmers is 56.5 years, and 30% of farmers has no education or just elementary school. The relationship among the environmental, socio-economic parameters and floristic structures of grasslands was studied using canonic-correspondence analysis. The impact of 16 parameters was analysed, of which six were determined not to be statistically significant. The occurrence of chosen plant species was analysed in relation to environmental and socioeconomic parameters. The efficiency of agro-environmental subsidies in relation to plant species diversity was evaluated. It was determined that the education and age of farmers influence the intensity of farming and consequently have an impact on the diversity of plants species and the conservation status of grasslands.

Within this research paper, the enforcement of agricultural policy measures for farms that have their agricultural lands within the Radensko Polje Landscape Park (RPLP) were studied. The purpose of the study was to evaluate the effectiveness of the additional payment for the extensive rearing of female bovine animals (ERB) and agri-environmental measures (AE measures) in terms of maintaining extensive agricultural systems or transitions from intensive systems to sustainable ones. This is especially desirable in the protected areas that also include landscape parks. The results of the survey of farmers of RPLP showed that both the ERB and AE measures are inefficient and fail to encourage farmers to implement more extensive farming. The main reasons for the poor enforcement of claims for ERB are intensive livestock production (milk production or bovine animals fattening), and the lack of information about the possibility of claim enforcement for ERB. Regarding AE measures, the main reasons for the failure are burdensome conditions and low financial compensation. Inventories of the composition of plant species on sample grasslands showed that the conditions of the habitats are still relatively good, because a relatively large number of species of high conservation value is present.

Common ragweed (Ambrosia artemisiifolia L.) spread across Europe and other regions is becoming a serious health and economic threat. A pot experiment was conducted in 2011 to determine effect of various nitrogen (N) (10, 100 kg/ha) and water supply regime on resource use efficiency of ragweed. Ragweed plants increased their dry matter production with increased water and N availability. Nitrogen use efficiency (NUE) was decreased with N addition and was not influenced by water availability. Mean nitrogen residence time (MRT) was longer at low N and water levels. In contrast, nitrogen productivity (NP), NUE and water use efficiency (WUE) were all increased with enhanced water supply. A trade-off between parameters of NUE was attributed to differential response of NP and MRT to soil fertility and water supply. Our results confirmed that ragweed displayed high adaptation to unproductive sites. However, ragweed’s greater plasticity in response to water availability compared to N availability suggest, that water supply plays important role in its invasion success and in combination with disturbance ragweed might further spread into more productive environments.

The main goal of the research was to compare the plant response to air pollutants in the rural environment (Zavodnje village) before and after the installation of a desulphurisation device at unit 5 of the Šoštanj Thermal Power Plant (Slovenia). The installation of the cleaning device for SO2 in the year 2001 caused very significant reduction of annual average SO2 emission and immission, while concentrations of dust particles, O3, NOx, and CO2 in Zavodnje remained unchanged. On the other hand the average concentrations of ozone during seasonal experimental period increased after 2001, but there were no significant differences in AOT40. The impact of O3 in combination with other air pollutants was studied at Zavodnje in the period 1996–2003 using white clover (Trifolium repens ‘Regal’) on the basis of visible ozone injuries of leaves, biomass reduction and by analysis of chosen biochemical stress parameters in leaves – the content of plant pigments and antioxidants. The effects of reduction of SO2 after 2001 were observed in the biochemical responses of white clover plants, which showed better vitality. Despite of that, there was no significant difference in the level of plant injury by ozone between the period 1996–2000 and period 2001–2003. Biomass ratio CN-S/CN-R was also unaffected.

Paper presents a larval cannibalism of green lacewings (Chrysoperla carnea), which was observed during the laboratory bioassay on non-target effect of entomopathogenic nematodes against green lacewings larvae. The most probable reason for larval cannibalism were undersized Petri dishes in which the bioassay was performed. Due to large number of larvae per surface unit, frequent crossing of green lacewings larvae appeared and this consequently lead to cannibalism. In most cases larger, elder larvae consumed smaller, younger larvae. Cannibalism increased with temperature rise and was the most intensive at 25 °C. At this temperature the larval mortality was 22.0 % after two days, while after four days the larval mortality reached 31.0 %.

Žuželke in pršice povzročajo podobne poškodbe kot jih povzroča tudi troposferski ozon (O3) na indikatorski rastlini plazeči detelji (Trifolium repens 'Regal'). Zastavili smo poskuse v katerih smo natančno popisovali in fotografirali poškodbe 6 različnih vrst sesajočih žuželk in pršic na plazeči detelji, ki smo jih primerjali s poškodbami na listih plazeče detelje, ki so nastale kot posledica velikih koncentracij ozona. Listne poškodbe v obliki nekroz smo opazovali na občutljivih in odpornih klonih plazeče detelje na Laboratorijskem polju Biotehniške fakultete v Ljubljani od maja do septembra 1998. V laboratoriju Inštituta za fitomedicino, na Biotehniški fakulteti, v Ljubljani, smo od avgusta do konca oktobra 2001 gojili žuželke in pršice in opazovali poškodbe zaradi sesanja živalic. V poskusu so bile: navadna pršica (Tetranychus urticae Koch), tobakov resar (Thrips tabaci Lindeman), vrsta uši Nearctaphis bakeri Cowen, dve vrsti stenic Halticus apterus Linnaeus in Trigonotylus coelestialium Kirkaldy in dvopikčasti škržatek (Cicadella viridis Linnaeus). Fotografije in natančne opise poškodb, zaradi različih vrst živalic in ozona, smo primerjali, med seboj. Poškodbe, bele kloroze, ki jih povzroča stenica Halticus apterus Linnaeus so bile največje med poškodbami preučevanih škodljivcev, hkrati pa so tudi najbolj podobne poškodbam, ki nastanejo zaradi velikih koncentracij ozona. Vsi ostali preučevani organizmi povzročajo drugačne vrste poškodb.

Test shallot plants Allium cepa L. var. ascalonicum were exposed to field conditions in research plots in the most polluted areas in Slovenia in the vegetation season in 1999. The intention of this research was to evaluate the influence of air pollution on mitotic activity in meristematictissues of root tips of bioindication plants. At each sampling site the mitotic activity was determined under field conditions and in a pot experiment. The maturated bulbs were collected from the field and after winter dormancies cytogenetic analyses were run on them in a lab. Root tips were fixed in Clark's fixative and afterwards stained with Schiff's reagent. Significant differences in the mitotic activity in different sampling plots in pot experiments were found. The results showed the presence ofcytotoxic substances at chosen sampling sites which caused the decrease of mitotic cell division.

The rate of exchange of CO2 between soil and atmosphere is controlled by atmospheric and soil physical and biological conditions. Predominant processes that produce carbon dioxide in soil are root and soil organism respiration and decomposition of organic matter. In our research, soil CO2 efflux in homogeneous soil samples was measured with dynamic chamber system LI-6400-09 employing infrared gas analyzer (IRGA). Simultaneously, soil and air temperature were measured and the data were later correlated with soil respiration. The measurements were performed at different day periods and at different weather conditions in order to determine the optimal measurement conditions. CO2 efflux was significantly lower (0.70 ± 0.14 m mol m-2 h-1) when measured in the morning with average soil temperature (12.2 ± 1.7 oC), compared to the measurements during the cloudy day with efflux (1.44 ± 0.23 m mol m-2 h-1), average soil temperature (16.4 ± 0.8 oC) and the sunny day efflux (2.24 ± 0.38 m mol m-2 h-1) with the highest average soil temperatures (21.2 ± 3.2 oC). The soil temperature accounted for 80.1 % of soil respiration variability. The Q10 value, calculated for soil CO2 efflux was 2.3. Thus, to collect an appropriate amount of comparable data replications, required due to high soil spatial variability, soil respiration measurements should be performed at relatively stable atmospheric conditions. The comparable flux measurements should be taken always at the same day period.

Mature 'Jonagold', 'Elstar' and 'Golden Delicious' apple trees on M9 rootstock were sprayed with the most frequently used apple thinning compounds in the years 1995, 1996 and 1997. Net CO2 assimilation rate (A), stomatal conductance (gs) and internal CO2 concentration (ci) of apple leaves were measured a few days after carbaryl (800 ppm), terbacil (50 ppm), NAA (15 ppm), NAAm (50 ppm), BA (50 ppm) and ethephon (300 ppm) application. The strongest A suppression of leaves parallel with gs reduction and enhanced ci was observed with terbacil on all cultivars for all years. Carbaryl, NAA, and BA reduced A on 'Jonagold' and 'Golden Delicious' in 1995 while 'Elstar' trees showed A depression of leaves after NAA application in 1997. NAAm and ethephone had no influence on A, gs or ci on any cultivar.

In apple tree (Malus domestica Borkh.) the correlation between the leaves net photosynthesis, the tree yield and the leaf area of the tree was investigated. The experiments were carried out on three apple cultivars ('Jonagold', 'Elstar Elshof', 'Idared') for the three planting systems. Net photosynthesis and the tree yield reached the highest medium value in the one row planting system, the tree row system followed, whereas the lowest values of both parameters were measured in the "V" planting system. The tree leaf area had the lowest value in one row planting system and the highest value in tree row system. In high density planting system with three planting distances 20 cm, 40 cm and 60 cm, the highest net photosynthesis was measured at the 40 cm distance for all four cultivars involved in the experiment ('Golden Delicius', 'Red Elstar', 'Jonagold', 'Idared'). The tree yield and the tree leaf area in the high-density planting system did not show correlation with net photosynthesis.

Several bioindication methods were applied in order to determine the area of influence of emissions from the Trbovlje Thermal Power Plant. From 1991 to 1996 epiphytic lichens were mapped at 260 sites in the area from Vače to Veliko Širje and from Prebold to Jatna. Ten experimental plots, differing in distance from the thermal power plant and their air pollution level, were chosen for detailed analyses of Norway spruce (Picea abies (L.) Karst). Assessing damage to the number and density of branches and needles and analyses of macronutrients, chlorophyll a, chlorophyll b, a carotene, b carotene, zeaxanthin, lutein and ascorbic acid were chosen as markers of air pollution impact on Norway spruce. The conclusion was drawn that the emission area of the power plant exceeds the limits of the area researched. Pollution is somewhat lower in the north-west part of the investigated area. Dobovec, Kovk, Ostenk, Ravenska vas and Retje are strongly polluted. In 1991 and 1992 high concentrations of ozone were detected in Zasavje by monitoring with tobacco cultivars (Nicotiana tabacum L.). This was also confirmed by observing the response of cultivars of white clover, beans, sunflower and selected natural species at Kovk. The mapping of lichens and the analysis of biochemical parameters of spruce needles proved to be a highly useful bioindication method.

The influence of various apple fruit thinning methods on photosynthetic activity and the content of photosynthetic pigments and ascorbic acid in the leaves was investigated. Thinning was implemented manually and with several chemicals (Carbaryl, Terbacyl, NAA, NAAm, BA, Ethephon). The experiment was carried out in 1995 on ‘Jonagold’ and in 1996 on ‘Jonagold’, ‘Elstar’, ‘Golden Delicious’. Cultivars of control trees, on which no thinning was implemented, were used for comparison. Except for the Carbaryl in 1995 and Terbacyl in 1995 and in 1996, which caused a decrease in photosynthesis, thinning had no influence on the content of photosynthetic pigments and ascorbic acid. With respect to these two vitality parameters, we can conclude that the chemicals used have no major effect on apple tree vitality.

An investigation of the impact of ozone on the appearance of leaf injuries and changes in selected biochemical parameters in white clover were conducted in frames of the research of the effects of ozone on growth and development on selected agricultural plants species. For this purpose, we used the methodology of the International Cooperative Programme-Crops (ICP-Crops). Two sampling sites in the vicinity of meteorological and air pollution measurement stations were chosen: Iskrba near Kočevje, as not polluted, rural area in Slovenia and Ljubljana as a site within larger city area. The presence of ozone and its phytotoxic effects was monitored using cultivars of white clover. The response of agricultural plants to ozone and other photooxidants was monitored using the prescribed protocol based on observation of typical ozone induced leaf chlorosis, harvesting of biomass and measurements of selected physiological and biochemical parameters in the leaves. We tried to correlate quantitative visible leaf damage with ozone measurements in the air. In our experiment we investigated the effect of ethylenediurea (EDU) treatment of white clover, which is considered to protect plants against ozone injuries. Our investigation confirmed that ozone concentrations measured in Slovenia can produce harmful effects on white clover. EDU did not totally protect white clover against ozone.

Fruit CO2 exchange at the time of fruit setting period was evaluated on mature cv. 'Jonagold' apple trees after 4 days artificial shading with 90 % photosynthetic photon flux (PPF) reduction and after NAA 15 ppm and BA 50 ppm applied immediately after the end of shading. Light reduction which accelerated fruitlets abscission very quickly had a depressive effect on fruits CO2 dark respiration rate (Rd) and gross assimilation rate (Ag) 3 days after the end of shading. Similarly, reduced Rd and less negative net CO2 assimilation rate (A) was recorded on fruitlets 7 days after NAA and BA application what is explained as a diminished metabolism of fruits starting with abscission. The fruitlets from shaded trees, which did not tend to abscission any more, showed an enhanced Rd and more negative A on 7th or 8th day after the end of shading. Ethylene evolution from fruits 2nd and 7th day after NAA 15 ppm application was enhanced comparing to control fruits. BA 50 ppm enhanced ethylene evolution on 2nd day after spraying, however on 7th day the ethylene evolution was lower than in control fruits. Healthy, not to drop inclined fruitlets retained on trees 7 days after shading treatment, showed stronger fruit ethylene production.

Ascorbic acid and photosynthetic pigments content in leaves of the apple tree (Malus domestica Borkh.) subjected to drought and white clover (Trifolium repens L.) exposed to high ozone concentrations were measured by high performance liquid chromatography in order to detect oxidative stress. Measurements showed a significant difference between stressed and control plants. Water deficit increased ascorbic acid and zeaxanthin, and decreased total chlorophyll (a+b) and b-carotene in apple tree leaves. High concentrations of ozone increased ascorbic acid, total carotenoids, neoxanthin, zeaxanthin and b-carotene, and decreased violaxanthin and antheraxanthin in white clover leaves. Observed changes in ascorbic acid and photosynthetic pigment content in leaves of tested apple tree and white clover plants indicate that oxidative stress may have occured under stress conditions used in our experiments.