Análise do perfil de metabólitos polares em tecido foliar de Eucalyptus spp

Abstract

Clonal propagation of the Eucalyptus, have been used in Brazil since the 60s, due to the characteristics of productivity, adaptability and rapid growth, especially Eucalyptus grandis and its hybrids, which have good performance to obtain paper pulp, and the E. benthamii that is resistant to mild temperatures followed by frost. The analysis of the metabolic profile for Eucalyptus species has not yet been explored, which leads to difficulties in the identification of gene expression phenotypes of commercial interest. Thus, the present study aimed to implement and evaluate the methodology typically used to obtain the metabolic profile in leaf tissue of two age stages (e.g. young and adult) of E. grandis and E. benthamii under field conditions. The metabolic profile was characterized by gas chromatography-mass spectrometry (GC-MS), this technique proved effective for obtaining a profile of polar metabolites, although it had less sensitive to nitrogen compounds and amino acids. The predominance of carbohydrates was observed in leaf tissue of the studied species, which may be related to the time of collection of the material under light intensity, non-reducing sugars such as sucrose have massive production during the photoperiod, and they are metabolized to other compounds during the night. The PCA, trimmed by statistical test indicated that there were significantly more metabolites that contribute to the distinction between the ages of leaf tissue, and the more reducing sugars are important in young tissue and non-reducing sugars, such as sucrose, are relevant in adult tissue. The presence of unique compounds in tissue E. benthamii such as phenylalanine, can justify the fact that this species is nominated to be used in energy, since this amino acid is directly related to lignin synthesis. Besides E. benthamii has greater abundance sucrose and sugar alcohols compounds than E. grandis, which is related to a better resistance to cold. No statistical differences were found between the concentrations of glucose and galactose which supports the non-use of E. benthamii for pulping.