Dendrochronological material of mountain pine (Pinus mugo ssp. uncinata) was collected from Engadina (Switzerland), climatic and pathological data were also compiled. Samples were prepared to further analyse the terpene profiles of trees attacked by Heterobasidion annosum in order to evaluate the possibility for using these profiles as markers for past disease outbreaks. This analysis was performed using a Perkin-Elmer gas chromatograph equipped with a dedicated automatic sampler for head-space analysis. Data were acquired and stored on the TotalChromTM chromatography software. The separation of enantiomeric monoterpenes was performed on a fused silica capillary column 30 m long and 0.25 mm diameter coating DB-WAX. The volatile compounds present in cortical samples were identified by comparing the retention times of recorded peaks with those obtained by injecting pure monoterpenes. The highest per cent agreement in the signs of the first-differences of two time series (Gleichläufigkeit) values with the reference chronologies and with the mean chronology of all the dead trees were found for the H. annosum mean chronologies. Comparing growth trends of dead trees with those of reference chronologies built from living trees, all dead trees show a more pronounced decreasing recent trend in ring-width. The amount of each monoterpene was expressed as a percentage of total monoterpenes. b-pinene, an unknown compound, -3-carene, a-pinene, b-myrcene and b-phellandrene were the major constituents. Terpene composition in tree rings remained stable across following years in non-infected trees while changing in attacked plants. Differences in terpene profiles were detected between the attacked and non-infected trees and discussion is focused on the relationships between terpene compositions and the attack of H. annosum. The time since death may be inferred for infected trees. These preliminary data warrant further studies on possibility to use terpene analysis and tree-ring investigation to monitor the time course of disease evolution on trees as they lay dying.
Tracking terpene profiles in tree rings of lay dying trees.
Michelozzi M;
2007
Abstract
Dendrochronological material of mountain pine (Pinus mugo ssp. uncinata) was collected from Engadina (Switzerland), climatic and pathological data were also compiled. Samples were prepared to further analyse the terpene profiles of trees attacked by Heterobasidion annosum in order to evaluate the possibility for using these profiles as markers for past disease outbreaks. This analysis was performed using a Perkin-Elmer gas chromatograph equipped with a dedicated automatic sampler for head-space analysis. Data were acquired and stored on the TotalChromTM chromatography software. The separation of enantiomeric monoterpenes was performed on a fused silica capillary column 30 m long and 0.25 mm diameter coating DB-WAX. The volatile compounds present in cortical samples were identified by comparing the retention times of recorded peaks with those obtained by injecting pure monoterpenes. The highest per cent agreement in the signs of the first-differences of two time series (Gleichläufigkeit) values with the reference chronologies and with the mean chronology of all the dead trees were found for the H. annosum mean chronologies. Comparing growth trends of dead trees with those of reference chronologies built from living trees, all dead trees show a more pronounced decreasing recent trend in ring-width. The amount of each monoterpene was expressed as a percentage of total monoterpenes. b-pinene, an unknown compound, -3-carene, a-pinene, b-myrcene and b-phellandrene were the major constituents. Terpene composition in tree rings remained stable across following years in non-infected trees while changing in attacked plants. Differences in terpene profiles were detected between the attacked and non-infected trees and discussion is focused on the relationships between terpene compositions and the attack of H. annosum. The time since death may be inferred for infected trees. These preliminary data warrant further studies on possibility to use terpene analysis and tree-ring investigation to monitor the time course of disease evolution on trees as they lay dying.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
