Techniques of ozone monitoring in a mountain forest region: passive and continuous sampling, vertical and canopy profiles

Ozone is the most harmful air pollutant for plant ecosystems in the Mediterranean and Alpine areas due to its biological and economic damage to crops and forests. In order to evaluate the relation between ozone exposure and vegetation injury under on-field conditions, suitable ozone monitoring techniques were investigated. In the framework of a 5-year research project aimed at ozone risk assessment on forests, both continuous analysers and passive samplers were employed during the summer seasons (1994-1998) in different sites of a wide mountain region (80 x 40 km2) on the southern slope of the European Alps. Continuous analysers allowed the recording of ozone hourly concentration means necessary both to calculate specific exposure indexes (such as AOT, SUM, W126) and to record daily time-courses. Passive samplers, even though supplied only weekly mean concentration values, made it possible to estimate the altitude concentration gradient useful to correct the altitude dependence of ozone concentrations to be inserted into exposure indexes. In-canopy ozone profiles were also determined by placing passive samplers at different heights inside the forest canopy. Vertical ozone soundings by means of tethered balloons (kytoons) allowed the measurement of the vertical concentration gradient above the forest canopy. They also revealed ozone reservoirs aloft and were useful to explain the ozone advection dynamic in mountain slopes where ground measurement proved to be inadequate. An intercomparison between passive (PASSAM, CH) and continuous measurements highlighted the necessity to accurately standardize all the exposure operations, particularly the pre- and postexposure conservation at cold temperature to avoid dye (DPE) activity. Advantages and disadvantages from each mentioned technique are discussed

Tropospheric Ozone In A Mountain Forest Area: Spatial Distribution And Its Relation With Meteorology And Emission Sources

Biological injuries to forest ecosystems in two lateral valleys of Valtellina (Italy) have been studied. The selected areas are characterized by different forest novel decline symptoms and ozone concentration levels. Analyses of meteorological and air quality data collected by fixed and mobile stations located in the two valleys are presented. Ozone concentration has been measured both by passive samplers and continues analyzers and the ozone vertical gradient in one valley has been determined. In order to investigate the relation between emission sources, ambient ozone levels and plant biological injuries, a modeling research project has been started. As preliminary results the wind field obtained by the application of two diagnostic meteorological models, MINERVE and CALMET, and the computation of the biogenic emissions are presented. Some examples of spatial distribution and temporal trend of the most important pollutants emitted by plants are discussed

Gestione sostenibile delle foreste Mediterranee e uso energetico delle biomasse forestali residuali

he book describes the reasons that led the Regional Department of Rural and Territorial Development to take part in the PROFORBIOMED Project. They can be summarized by the need to dispose of a tool for the sustainable management of all the state-owned forests of the Region. As a matter of fact, the Project aims at developing a model of sustainable forest management, through the recovery and reuse of wood scraps from ordinary silvicultural operations, to be used for the production of power and heat inside of a process adopting natural renewable energy sources. The main actions taken and the methodologies adopted are described, as well as the principles and instruments required for the setting up and execution of the work. Some of the most relevant are: the drafting of “Forest Management Plans”, the “Short Supply Chain” and the “Biomass Traceability Protocol”, together with the application of “Best Practices” of Management and the “Monitoring of impacts” caused by the woody biomass extraction procedures. The “forest – wood – energy” chain developed and proposed is exclusively related to the territory pertaining to one municipality, and with CHP plants fed with biomass exclusively produced within the territory of each municipality, in strict compliance with the “sustainable forest management” principles, as well as with the fundamental principle of “short supply chain”. For these reasons the CHP plans proposed shall be sized according to the biomass available in each municipality, with the possibility of integrating residual forest biomass with other waste wood resources potentially available in the territory and coming from prunings in agricultural activities. Therefore, the replicable model prepared and proposed by PROFORBIOMED aims at appraising from the economic point of view a waste product, such is currently considered the residual forest biomass from the forests of Sicily, and at the same time significantly improving the natural environment, thanks to the reduction in oil consumption

Effects of abscisic acid, gibberellic acid and fusicoccin on the transmembrane potential during the early phases of germination in radish (Raphanus sativus) seeds

During germination, the transmembrane electric potential (PD) of cortical cells of the embryonal axis of radish seeds (Raphanus sativus L.) rises from-120 mV initially to a maximum of-150 mV after 5 h incubation, then falls again to stable values of around-120 mV. Treatments inhibiting germination block the transitory PD increase. Administration of uncoupling agents or low temperatures, during the process of germination, produces a marked fall of the PD transitory increase. Abscisic Acid has a parallel inhibitory effect on PD and germination, while fusicoccin produces a rise in both; administration of abscisic acid with fusicoccin inhibits germination, while the PD remains at the high levels given by fusicoccin. These results are discussed in relation to ion exchange at membrane level

Effect of ABA, GA and fusicoccin on the transmembrane potential during early phases of germination in radish seeds

In the first stages of germination of seeds of the radish (Raphanus sativus) an outflow of K takes place which is immediately followed by its reincorporation; substances which stimulate germination accelerate the reincorporation of K while germination inhibitors slow it down. During early stages of germination the capacity to incorporate K develops precociously and parallel to the germination of seeds treated with phytoregulators. Further-more, a Mg K -dependent ATP-ase activity linked to the membrane, probably invol-ved in transport of K , is found to develop in step with germination. Germination of the seed thus seems to be correlated with the increase in activity linked to the plasmatic membrane. ( 1 ) In order to obtain information as to the state of organization and function of the plasmatic membrane, a study was made of the variations of tra,:!smembrane electric potential during early stages of germination l:oth in seeds treated with phytoregulators and in untreated seeds. PD ( potentiaI difference ) measurements were made on seeds soaked at 0 C and made to germinate in water at 26 C under agitation after removal of the coats. Such measurements were in all cases preceded by a period of equilibration of 30 min in KCI 0.5mM pH 6 with or without the presence of the phytoregulators used. Preliminary tests were made measuring the PO of cells of the embryonal axis, exc!uding the apical zones, and of the cortical cells of the cotyledons. The results showed that the PD of the cortical cells (2nd-3rd layer) both of the embryonal axis and of the cotyledons ' reaches practically the same value; later studies were made on the cortical cells of the embryonal axis from 2 to 4mm from the root apex since this area permits greater reproducibility and stability of electrophysiologic measurements . During early stages of germination in water the PD rises from a value of -120 mV to -150 mV at 5 h. This successively falls back to stable values around -120 mV after 15 h. In seeds trated with FC ( fusicoccin ), a germination-stimulating phytoregulator which raises K uptake and protons extrusion of protons into the medium, the pattern of PD values observed during germination is similar to that observed in controls but with markedly-higher absolute values; a value of -175 mV after 5 h and over long time intervals ( 15 h) the value becomes stab le around -145 mV . GA3, in agreement with observations for K uptake, would not appear to produce substantial changes in patterns of PO values with respect to controls in the time interval studied. Treatment from the start with ABA in concentrations sufficient to inhibit germination and K uptake also prevents hyperpolarization which is to be observed in controls during the first few hours; PO is practically co nstant in time a t va lues around -110 mV. Removal of ABA from the medium rapidly (in 20 min) produces hyperpolarization o f the PO up to approximately the levels found in the controls which have only been soaked: the increase observed appears to be linked to the favourable effect on seed germination o f the removal of the ABA. These findings can be summed up in the observation that the hyperpolarization which accompanies the early stages of germination is suppressed when germination is inhibited by ABA, whilst on the other hand the initial hyperpolarization and PO level are found to be greater when germination is stimulated by FC. Comparison o f such data with findings relating to K + uptake show that the initial rise of negative potential is not due to loss of K by the cells of the seed. In fact, in seeds grown in ABA the initial hyperpolarization does not take place, and the reincorporation of K is also suppressed. On the contrary it would seem that hyperpolarization can rather be attributed to the activation of an energy-dependent electrogenic mechanism, which is presumably also responsible for the increase of K uptake. (1) Cocucci,S.and Cocucci,M. Plant Science Letters 10,85 (1977) ( 2 ) Lado,P.,Rasi-Caldogno,F.and Colombo,R. Physiol.Plant. 34,359 (1975) 67