Needle terpene concentrations and emissions of two coexisting subspecies of Scots pine attacked by the pine processionary moth (Thaumetopoea pityocampa)

Achotegui-Castells A., Llusia J., Hodar J.A., Penuelas J. (2013) Needle terpene concentrations and emissions of two coexisting subspecies of Scots pine attacked by the pine processionary moth (Thaumetopoea pityocampa). Acta Physiologiae Plantarum. 35: 3047-3058.
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Doi: 10.1007/s11738-013-1337-3

Resum:

Mediterranean pine forests are often attacked by caterpillars of Thaumetopoea pityocampa (Lep., Thaumetopoidae), one of the most important defoliators in the Mediterranean region causing large economic losses and ecological effects. The needle terpene concentrations and emissions may play a key role in the defense of pines. We studied two subspecies of Pinus sylvestris, nevadensis (an endemic and relict subspecies) and iberica, with different levels of caterpillar attack in Sierra Nevada mountains (Spain). GC-MS analyses showed large total concentrations of terpenes (6 to 39 mg g-1 of dry weight) in the needles of both subspecies under field conditions. Concentrations were 25 % higher in "Non-Attacked Trees" (NATs) of the iberica than in the nevadensis subspecies. The branches of NATs had terpene concentrations 20 % higher than those of "Attacked Branches of attacked trees" (ABs). Within attacked trees, the "Non-Attacked Branches" (NABs) also had terpene concentrations 20 % higher than those of ABs. Mainly α-pinene and germacrene D had higher concentrations in NATs and NABs than in ABs. Some terpenes had higher concentrations in NABs than in NATs, indicating possible systemic reactions. In subsp. nevadensis, the percentage of monoterpenes relative to total terpenes was higher in ABs than in other attack states. The rates of emission in nevadensis (standardized to 30 °C) were ca. three times higher in ABs than in NABs and NATs. These results suggest that the lower terpene concentrations and high percentages of monoterpenes in ABs were produced by a combination of emission losses and terpene induction in response to herbivorous attack. © 2013 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.

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Identifying the origin of atmospheric inputs of trace elements in the Prades Mountains (Catalonia) with bryophytes, lichens, and soil monitoring

Achotegui-Castells A., Sardans J., Ribas À., Peñuelas J. (2013) Identifying the origin of atmospheric inputs of trace elements in the Prades Mountains (Catalonia) with bryophytes, lichens, and soil monitoring. Environmental Monitoring and Assessment. 185: 615-629.
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Doi: 10.1007/s10661-012-2579-z

Resum:

The biomonitors Hypnum cupressiforme and Xanthoria parietina were used to assess the deposition of trace elements and their possible origin in the Prades Mountains, a protected Mediterranean forest area of NE Spain with several pollution sources nearby. Al, As, Cd, Co, Cu, Cr, Ni, Pb, Sb, Ti, V, and Zn were determined in 16 locations within this protected area. Soil trace element concentrations were also ascertained to calculate enrichment factors (EF) and use them to distinguish airborne from soilborne trace element inputs. In addition, lichen richness was measured to further assess atmospheric pollution. EF demonstrated to be useful not only for the moss but also for the lichen. Cd, Cr, Cu, Ni, and Zn presented values higher than three in both biomonitors. These trace elements were also the main ones emitted by the potential sources of pollutants. The distance between sampling locations and potential pollution sources was correlated with the concentrations of Cu, Sb, and Zn in the moss and with Cr, Ni, and Sb in the lichen. Lichen richness was negatively correlated with lichen Cu, Pb, and V concentrations on dry weight basis. The study reflected the remarkable influence that the pollution sources have on the presence of trace elements and on lichen species community composition in this natural area. The study highlights the value of combining the use of biomonitors, enrichment factors, and lichen diversity for pollution assessment to reach a better overview of both trace elements' impact and the localization of their sources. © 2012 Springer Science+Business Media B.V.

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