Keywords

biofuels, soil, ethanol, lignin, genetically modified organisms, root, carbon

Presentation Type

Talk

Research Abstract

Biofuels are plant-derived fuel sources, and are being developed as renewable energy to meet increasing global energy demand. Some biofuels use genetically modified plants with altered lignin chemistry to be less of a barrier for the extraction of cellulose. The lignin structure of stems and leaves of genetically modified organisms (GMO’s) are known, however, root structure is often not characterized. Plant roots are thought to be the main contributor of carbon to soils during degradation and therefore the chemical composition of roots have a large control on the chemistry of soil organic matter. The potential impact of biofuel GMO’s on root chemistry is an unexplored impact of GMO biofuels application. Using carbon-13 labelled tetramethylammonium hydroxide (13C-TMAH) pyrolysis and gas chromatography-mass spectrometry (GC-MS), the chemical structure of lignin in roots can be analyzed and determined. Root tissue from field-isolated hybrid poplar plants (species with genus Populus) that were genetically modified to vary the proportion of lignin structural components were sampled to assess if known variations in stem lignin chemistry reflects in fine root (<1mm ) tissue. Looking at known guaiacyl derivative compounds, a large variation in percent dihydroxyl composition of original compounds was shown, as opposed to the small variation in known syringyl derivatives. It was also found that percent composition of syringyl, guaiacyl, and cinnamyl compounds varied in each set of samples, suggesting that genetic modifications targeting stem/wood tissue significantly influence root chemistry and probably structure. This has potential implications for root decomposition, soil chemistry, nutrient uptake, and water storage.

Session Track

Earth and Space Science

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Aug 3rd, 12:00 AM

Root Phenolic Carbon Chemistry from Genetically Modified Poplars

Biofuels are plant-derived fuel sources, and are being developed as renewable energy to meet increasing global energy demand. Some biofuels use genetically modified plants with altered lignin chemistry to be less of a barrier for the extraction of cellulose. The lignin structure of stems and leaves of genetically modified organisms (GMO’s) are known, however, root structure is often not characterized. Plant roots are thought to be the main contributor of carbon to soils during degradation and therefore the chemical composition of roots have a large control on the chemistry of soil organic matter. The potential impact of biofuel GMO’s on root chemistry is an unexplored impact of GMO biofuels application. Using carbon-13 labelled tetramethylammonium hydroxide (13C-TMAH) pyrolysis and gas chromatography-mass spectrometry (GC-MS), the chemical structure of lignin in roots can be analyzed and determined. Root tissue from field-isolated hybrid poplar plants (species with genus Populus) that were genetically modified to vary the proportion of lignin structural components were sampled to assess if known variations in stem lignin chemistry reflects in fine root (<1mm >) tissue. Looking at known guaiacyl derivative compounds, a large variation in percent dihydroxyl composition of original compounds was shown, as opposed to the small variation in known syringyl derivatives. It was also found that percent composition of syringyl, guaiacyl, and cinnamyl compounds varied in each set of samples, suggesting that genetic modifications targeting stem/wood tissue significantly influence root chemistry and probably structure. This has potential implications for root decomposition, soil chemistry, nutrient uptake, and water storage.