Sistemas modelos de formação de lignina utilizando recursos sintéticos e celulares de Eucalyptus grandis (Hill ex Maiden). / Systems models of lignin formation using synthetic and cellular resources of Eucalyptus grandis (Hill ex Maiden).

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The main objective of this research was to work out models for the study of the lignification. Eucalyptus grandis seedlings were produced in vitro, and the stem segments explants were used to obtain friable callus. For such, the auxins tested were TDZ, 2,4-D, NAA and IAA. The treatments with 50,0 μM 2,4-D; 3,0 μM TDZ and in the absence of growth regulator didn t present callus formation. After 210 days, it was chosen a callus formed in the culture medium added with 2,5 μM of TDZ. The selected callus was maintained in the same treatment, however, in liquid medium and under agitation for 60 days at 25 C in the darkness, to induce cellular wall and extracellular lignin formation. After this period, the cells suspensions were treated in the following order: MS medium supplemented with sucrose, 2,4-D + kinetin, coumaric acid and without extra supplement. The cells were maintained in these treatments for 30 days. It was used a completely randomized design with four replications. Each plot consisted of an Erlenmeyer with 125 ml of cells suspension culture. For cellular wall lignin extraction and determination, it was used the method of lignin thyoglicolate. The concentration of cellular wall and extracellular lignins were evaluated by UR. For data normality verification it was used the Lilliefors test. The results were statistically analyzed by variance analysis and by Tukey test at 5% level of significance. The highest lignin concentration in the cellular wall (371.4200 ppm) was verified in the treatment EG1pc 0,0584 μM of sucrose. Extracellular lignins were also analyzed with Wiesner reagent, H NMR and 13C NMR. The highest concentration (134.3167 ppm) of extracellular lignins was verified in the treatment EG3e of 100μM coumaric acid). However, with the results obtained in H NMR and CNMR analysis, it was not possible to characterize the polymerization of pure extracellular lignin. A very useful tool for lignification study is the dehydrogenized polymerization (DHP) in vitro. DHPs were produce in cells suspension filtered medium (substrate) at different treatments. For each treatment, it was added H2O2, peroxidase or H2O2 + peroxidase. The DHPs production was done in MS culture medium (without the prior cultivation of cells) as a substrate. It was added to MS medium three different solutions (coniferyl or sinapyl alcohol, peroxidase and the H2O2) by dripping. The products of DHP and the filtered were analyzed by IR and H NMR. The DHPs produced in medium MS without the previous growth of the cells, were analyzed by H NMR and CNMR. The IR spectra didnt present any sign in the zone of 1500 cm-1. H NMR also showed no formation of DHPs. Nevertheless, in the, cells suspensions both in H NMR and in CNMR analysis presented signs of DHPs, except the DHP1c (MS + 0,0584 μM sucrose). H NMR presented: 3.86; 6.92; and 4.71 ppm and the CNMR: 134,26; 88,21; 65,17; 55,90; and 20,75 ppm.

ASSUNTO(S)

eucalyptus grandis lignin calogenesis tecnologia e utilizacao de produtos florestais lignina eucalyptus grandis calogênese

ACESSO AO ARTIGO

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