Internode structure and cell wall composition in maturing tillers of switchgrass (Panicum virgatum. L)

Abstract

Sarath, Gautam; Baird, Lisa M.; Vogel, Kenneth P.; and Mitchell, Robert B., "Internode structure and cell wall composition in maturing tillers of switchgrass (Panicum virgatum. L)" (2007 Abstract This work examined cell composition gradients in maturing tillers o f switchgrass (Panicum virgatuln L.) with the aim o f developing baseline information on this important forage and biomass crop. Flowering tillers were collected from plants raised from seeds in a greenhouse and field, harvested at soil level and separated into internodes beginning with the node subtending the peduncle. Internodes were analyzed using microscopy, by fiber digestion, high-performance liquid chromatography and by gas chromatography-mass spectrometry to obtain anatomical and compositional data. Microscopy demonstrated the development and maturation o f cortical fibers which eventually became confluent with the fiber sheath surrounding vascular bundles in the lower internodes. Detergent fiber analysis indicated increasing cellulose and lignin contents and decreases in cell solubles

Genetic background impacts soluble and cell wall-bound aromatics in brown midrib mutants of sorghum

“…Soluble aromatic components were extracted into aqueous methanol and analyzed using a Beckman programmable gradient HPLC as described previously (Sarath et al 2007). Phenolic components in peaks resolved by HPLC were identiWed by collecting the eluate under major peaks, followed by analysis by gas chromatography-mass spectrometry (GCMS).…”

“…Total aromatics present in aqueous methanol extracts from sorghum stems were identiWed as described above, but without prior separation by HPLC. Both soluble phenolics and aromatics obtained as described above, and ester-linked pCA and FA extracted from puriWed cell walls (Iiyama et al 1990), were analyzed as their silyl esters using N,O-bis-(trimetylsilyl)triXuoroacetamide and trimethylchlorosilane reagent according to manufacturer-recommended protocol (Pierce Chemical Company, Rockford, IL; Sarath et al 2007). Standard curves for diVerent phenolics were generated using authentic compounds obtained from commercial vendors.…”

Opportunities and roadblocks in utilizing forages and small grains for liquid fuels

“…The ground parenchyma display varying levels of secondary wall formation and its subsequent ligniWcation's appears to be genotype, environment, and maturity dependent [34,83]. These data indicate that harvesting heights and time of harvest will impact biomass quality and its eventual conversion to ethanol or bioenergy [3,26,83]. Variations in biomass quality and convertibility arise from the ratio of leaves to stems, and the amount of starch and simple sugars relative to cell wall accreted polymers.…”

“…For switchgrass cultivar Kanlow, the basal internodes contained almost twice the amount of lignin compared to the most apical internode [83]. In switchgrass tillers, the xylem, a band of cortical sclerenchymatous Wbers just beneath the epidermis, and the Wber sheath surrounding the vascular bundles are most highly ligniWed tissues [83] (Fig.…”

Suspected Selective Herbivory of Bioenergy Grasses by Meadow Voles (<em>Microtus pennsylvanicus</em>)

“…If this is the case, breeding programs that aim to reduce levels of lignins and other phenolics in certain plants to improve their use as biomass or forage (e.g., Sarath et al 2007) could also make them more palatable to unwanted herbivores. Plant tissue analyses could be used to compare levels of photoprotective compounds in field-and greenhouse-grown plants as a first step in evaluating this hypothesis, followed by palatability tests with selected herbivores.…”