Naslov
Preliminary report on epicuticular wax structure in Black pine needles affected by SO2 emitted from thermal power plant Plomin (Croatia)

Autori
Cesar, Vera ; Užarević, Zvonimir ; Potočić, Nenad ; Seletković, Ivan ; Lepeduš, Hrvoje

Izvornik
Periodicum biologorum (0031-5362) 107 (2005), 3; 357-360

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Pinus nigra ; air polution ; sulphur ; epicuticular wax

Sažetak
Background and purpose: The sulfur dioxide emitted from Plomin thermal power plant, Croatia, has been shown to have great influence on sulfur concentration in Black pine (Pinus nigra Arn.) needles. Since 1999 the emission of SO2 has been significantly lowered. Previous investigation revealed that the lowering of S-concentrations in Black pine needles started about two years after the drop of SO2 concentrations in air. The aim of this study was to examine the appearance of epicuticular waxes around stomata of previous- season Black pine (Pinus nigra Arn.) needles. Also, we tried to correlate S-concentration in the needles with the S-deposition on needle surface.Materials and Methods: previous -year needles were collected from the upper crown of Black pine (Pinus nigra Arn.) trees grown at different distances from the Plomin thermal power plant: zone I - less than 10 km, zone II - 10-20 km and zone III - 20-30 km. Chemical analysis included determination of total sulfur concentration. S-deposition on needle surface was determined by the energy dispersive X-ray microanalysis (EDX). The investigation of epicuticular wax micromorphology was done by scanning electron microscopy (SEM). A hundred stomata per zone were counted and tge degree of epicuticular wax degradation was assesed. Results: Sulfur concentrations in the previous-season Black pine needles were the same for all three zones. S- deposition was also practicaly the same for all zones. Although the highest value was recorded in zonr III, there was no statistical significance in respect to other two zones. Epicuticular wax structure revealed that all analyzed stomata could be classified either as stage 4 (51-80% covered by amorphous wax) or stage 5 (81-100% covered by amorphous wax) of injury. Stages 1, 2 and 3 were totaly absent. Stages 4 and 5 were differentally represented in each particular zone: the increase in the proportion of stage 5 in respect to the stage 4 was significant when zones I and III were compared. Conclusions: Despite the absence of any significant differences between the trees grown at different distances from the emission source, with regard to needle S content as well as the S deposition on needle surfaces, changes in epicuticular wax micromorphology were observed. higher percentage of stage 5 of wax injury in zone I than in zone III indicates higher environmental pressure that was present in zone I over the time of needle exposure.

Izvorni jezik
Engleski

Znanstvena područja
Biologija, Biotehnologija

POVEZANOST RADA