RESUMO
The dynamics of forest ecosystems worldwide have been driven largely by climatic teleconnections. El Niño-Southern Oscillation (ENSO) is the strongest interannual variation of the Earth's climate, affecting the regional climatic regime. These teleconnections may impact plant phenology, growth rate, forest extent, and other gradual changes in forest ecosystems. The objective of this study was to investigate how Pinus cooperi populations face the influence of ENSO and regional microclimates in five ecozones in northwestern Mexico. Using standard dendrochronological techniques, tree-ring chronologies (TRI) were generated. TRI, ENSO, and climate relationships were correlated from 1950-2010. Additionally, multiple regressions were conducted in order to detect those ENSO months with direct relations in TRI (p < 0.1). The five chronologies showed similar trends during the period they overlapped, indicating that the P. cooperi populations shared an interannual growth variation. In general, ENSO index showed correspondences with tree-ring growth in synchronous periods. We concluded that ENSO had connectivity with regional climate in northern Mexico and radial growth of P. cooperi populations has been driven largely by positive ENSO values (El Niño episodes).
Assuntos
El Niño Oscilação Sul , Pinus/crescimento & desenvolvimento , México , Microclima , Árvores/crescimento & desenvolvimentoRESUMO
The essential oils (EOs) of two populations of Azorella cryptantha (Clos) Reiche, a native species from San Juan Province, were obtained by hydrodistillation in a Clevenger-type apparatus and characterized by GC-FID and GC/MS analyses. The compounds identified amounted to 92.3 and 88.7% of the total oil composition for A. cryptantha from Bauchaceta (Ac-BAU) and Agua Negra (Ac-AN), respectively. The EO composition for the two populations was similar, although with differences in the identity and content of the main compounds and also in the identity of minor components. The main compounds of the Ac-BAU EO were α-pinene, α-thujene, sabinene, δ-cadinene, δ-cadinol, trans-ß-guaiene, and τ-muurolol, while α-pinene, α-thujene, ß-pinene, γ-cadinene, τ-cadinol, δ-cadinene, τ-muurolol, and a not identified compound were the main constituents of the Ac-AN EO, which also contained 3.0% of oxygenated monoterpenes. The repellent activity on Triatoma infestans nymphs was 100 and 92% for the Ac-AN and Ac-BAU EOs, respectively. Regarding the toxic effects on Ceratitis capitata, the EOs were very active with LD(50) values lower than 11 µg/fly. The dermatophytes Microsporum gypseum, Trichophyton rubrum, and T. mentagrophytes and the bacterial strains Escherichia coli LM(1), E. coli LM(2), and Yersinia enterocolitica PI were more sensitive toward the Ac-AN EO (MIC 125 µg/ml) than toward the Ac-BAU EO. This is the first report on the composition of A. cryptantha EO and its anti-insect and antimicrobial properties.
Assuntos
Anti-Infecciosos/química , Apiaceae/química , Inseticidas/química , Óleos Voláteis/química , Óleos de Plantas/química , Animais , Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Argentina , Bactérias/efeitos dos fármacos , Infecções Bacterianas/tratamento farmacológico , Fungos/efeitos dos fármacos , Humanos , Insetos/efeitos dos fármacos , Inseticidas/isolamento & purificação , Inseticidas/toxicidade , Micoses/tratamento farmacológico , Óleos Voláteis/isolamento & purificação , Óleos Voláteis/farmacologia , Óleos de Plantas/isolamento & purificação , Óleos de Plantas/farmacologiaRESUMO
The antifungal, antibacterial, and insect-repellent activities of the essential oils (EOs) of Acantholippia seriphioides, Artemisia mendozana, Gymnophyton polycephalum, Satureja parvifolia, Tagetes mendocina, and Lippia integrifolia, collected in the Central Andes area, province of San Juan, Argentina, were investigated. The dermatophytes Microsporum gypseum, Trichophyton mentagrophytes, and T. rubrum were inhibited by the EOs of G. polycephalum, L. integrifolia, and S. parvifolia, with minimum inhibitory concentrations (MICs) between 31.2 and 1000â µg/ml. Moreover, all EOs presented moderate activity against the bacteria tested, and the L. integrifolia and G. polycephalum EOs showed excellent repellent properties against Triatoma infestans, the Chagas disease vector, with repellency values between 60 and 100%. The A. seriphioides, G. polycephalum, and L. integrifolia EOs, obtained by hydrodistillation, were characterized by GC-FID and GC/MS analyses. The highest number of components (40) was identified in L. integrifolia EO, which, along with that of A. seriphioides, contained important amounts of oxygenated monoterpenes (44.35 and 29.72%, resp.). Thymol (27.61%) and carvacrol (13.24%) were the main components of A. seriphioides EO, and borneol, lippifoli-1(6)-en-5-one, and terpinen-4-ol (>8.5%) were the principal compounds of L. integrifolia EO. These results support the idea that oxygenated monoterpenes are the bioactive fractions of the EOs. Finally, the study shows that these Andean species might be used to treat superficial fungal infections and to improve the local Chagas disease situation by vector-control.
Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Repelentes de Insetos/farmacologia , Óleos Voláteis/farmacologia , Plantas Medicinais/química , Animais , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antifúngicos/química , Antifúngicos/isolamento & purificação , Argentina , Bactérias/efeitos dos fármacos , Infecções Bacterianas/tratamento farmacológico , Doença de Chagas/tratamento farmacológico , Fungos/efeitos dos fármacos , Repelentes de Insetos/química , Repelentes de Insetos/isolamento & purificação , Insetos/efeitos dos fármacos , Micoses/tratamento farmacológico , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificaçãoRESUMO
Essential oils from four species of the genus Tagetes L. (Asteraceae, Helenieae) collected in Tucumán province, Argentina, were evaluated for their chemical composition, toxicity, and olfactory activity on Mediterranean fruit fly Ceratitis capitata Wiedemann adults and for repellent properties on Triatoma infestans (Klug) (Chagas disease vector). Yields of essential oils range from 0.2 to 0.8% (v/w). The same main constituents among Tagetes minuta L., Tagestes rupestris Cabrera, and Tagetes terniflora Kunth, (cis-trans)-ocimenes, (cis-trans)-tagetones, and (cis-trans)-ocimenones showed important differences in their relative compositions. Tagetes filifolia Lag. was characterized by the recognized phenylpropanoids methylchavicol and trans-anethole as the main components. LD(50) was ≤20 µg/insect in topical bioassays. T. rupestris was the most toxic to C. capitata females, whereas the other oils presented similar toxicities against males and females. Tagetes rupestris oil attracted both sexes of C. capitata at 5 µg, whereas T. minuta showed opposite activities between males (attractant) and females (repellent). Oils from T. minuta and T. filifolia were the most repellent to T. infestans. The results suggest that compositions of essential oils influence their insecticidal and olfactory properties. The essential oils from Tagetes species show an important potential as infochemical agents on insects' behaviors. This study highlights the chemical variability of essential oils as a source of variation of anti-insect properties.