A especiação dos monoterpenos em uma floresta da Amazônia central
Plants produce and emit a large array of volatile metabolites termed biogenic volatile organic compounds (BVOCs) as an integral part of primary and secondary metabolism. Monoterpenes are BVOCs from the largest family of plant natural products, the terpenoids. Despite orders of magnitude differenc...
| Autor principal: | Jardine, Angela Beth |
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| Grau: | Tese |
| Idioma: | por |
| Publicado em: |
Instituto Nacional de Pesquisas da Amazônia - INPA
2020
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| Assuntos: | |
| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/12667 http://lattes.cnpq.br/1710366201594395 |
| Resumo: |
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Plants produce and emit a large array of volatile metabolites termed biogenic volatile
organic compounds (BVOCs) as an integral part of primary and secondary metabolism.
Monoterpenes are BVOCs from the largest family of plant natural products, the terpenoids.
Despite orders of magnitude difference in atmospheric reactivity and great diversity in
biological functioning, little is known about monoterpene speciation in tropical forests. Using
thermal desorption-gas chromatography-mass spectrometry techniques, twelve volatile
monoterpenes were identified and quantified in a central Amazon terra firma rainforest
including the first ambient air observations of the highly reactive cis-β-ocimene and trans-β-
ocimene. At the ecosystem scale, monoterpene mixing ratios in the ambient air were greatest
at the top of the canopy where light and temperatures are greatest. Leaf level monoterpene
emissions were found to be light dependent among the Amazon trees sampled in the field.
However, during drought stress conditions that led to leaf senescence, leaf monoterpene
emissions were found to be first light dependent followed by temperature dependent and an
acted as an early indicator of leaf lipid peroxidation. Further, leaf monoterpene emissions
revealed a strong non-linear relationship with net photosynthesis (Pn), dedicating up to 2% of
Pn to monoterpene emissions at leaf temperatures up to 30ºC and continuing to rise as leaf
temperatures increased. These results suggest that highly reactive monoterpenes may play
important roles as antioxidants protecting photosynthesis in plants and serve as near-canopy
sources of secondary organic aerosol precursors through atmospheric photooxidation
reactions. |