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The first metabolic study of the impact of elevated CO (590 µL CO L) levels on the leaves and buds of Coffea arabica L. plants is reported. A novel sequential statistical mixture design strategy allowed optimization of both the extraction and mobile phase solvent systems to increase differences detected in metabolites of Coffea arabica L. plants and buds. Factor analysis showed that the 227 and 273 nm bands of the 1:1:1 ternary ethyl ether - dichloromethane - methanol mixture spectra resulted in discrimination of elevated CO extract samples from those obtained from leaves grown in a current level CO atmosphere (390 µL CO L) of leaf sample extracts. DAD-HPLC spectral peak evidence showed a 32% increase in absorbance of the 273 band for the enriched CO leaf extracts. This band has been assigned to caffeine-like substances and confirmed by the mass spectral signal at m/z 195 ([M + H]). No enrichment band increases were found for kahweol, kaempferol and quercetin that had presence confirmed by mass spectral analysis. No epigenetic effect of this metabolic profile was found in new leaves after the addition of CO stopped. Enriched CO perturbation of the bud metabolite were much smaller than for the leaf samples. Absorbance increases in the 228 nm and decreases in the 235 nm bands play a prominent role in the discrimination of enriched CO buds from the controls in the pure dichloromethane extracting solvent. This global metabolome strategy allows the monitoring of chemical groups of plants susceptible to environmental changes as well as elucidate metabolic variations in complex matrices of biochemical responses.

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The effects of water-deficit stress on irrigated and unirrigated field plants of Coffea arabica L. genotype IAPAR 59 were investigated. Plant extracts were obtained following an ethanoldichloromethane-hexane statistical mixture design. Proton nuclear magnetic resonance (1 H NMR) fingerprints of the extracts were discriminated using factor analysis (FA) and hierarchical clustering techniques. Extracts from the 1:1:1 ternary mixture presented the largest discriminations compared with those from the pure solvents or their 1:1 binary mixtures. Metabolites resulting from fermentation processes and nutritional deficiencies as well as senescence and abscission precursors such as lactate, arginine and methionine were prevalent in unirrigated plants that can provoke expressive decreases in bean productivity as well as premature plant aging. Amino acids that control regulatory, physiological processes and soil salinization have higher concentrations in the irrigated plants. The NMR assignments of eighteen substances observed here were confirmed by electrospray ionization mass spectrometry.

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