Cellulose and the Evolution of Plant Life

Duchesne, Luc; Larson, Douglas W.

doi:10.2307/1311160

Cited by 86 publications

(33 citation statements)

References 19 publications

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“…Even if lichens with N # -fixing cyanobacterial photobionts are characterized by higher N concentrations in the thallus (2-4%) (Rai, 1988 ;, these species still have lower PSU densities than plant leaves with similar nitrogen status (Palmqvist et al, 1998). This is apparently caused by the requirement for nitrogen for hyphal extension and the formation of fungal cell wall (chitin) (Palmqvist et al, 1998), a trade-off that is not shared by plants and bryophytes because they have cell walls containing cellulose (Duchesne & Larson, 1989).…”

Section: Light and Nitrogen Relationsmentioning

confidence: 99%

Tansley Review No. 117

Palmqvist

2000

New Phytologist

218

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Lichens are nutritionally specialized fungi (the mycobiont component) that derive carbon and in some cases nitrogen from algal or cyanobacterial photobionts. The mycobiont and photobiont live together in an integrated thallus, but they lack specific tissue for the transport of metabolites and resources between them. Carbon is acquired through photosynthesis in the photobiont, which is active when the lichen is wet and exposed to light. Lichen photosynthesis is limited primarily by water, light and nitrogen, but can also be constrained by slow diffusion of CO # within the wet thallus. The assimilated carbon is exported from photobiont to mycobiont, which also predominates in terms of biomass, and apparently regulates the size of the photobiont population. It has therefore generally been assumed that most of the carbon is used for growth and maintenance of the fungal hyphae. However, the extent of photobiont respiration in relation to mycobiont respiration has seldom been quantified ; neither do we know the pool sizes of various carbon sinks within lichens. Owing to this lack of fundamental data we do not know whether, or how, carbohydrate resources are regulated to maintain an optimal balance between energy input and expenditures in these symbiotic organisms. This review summarizes data on growth, carbon gain and carbon expenditures in lichens, with particular emphasis on factors determining the photosynthetic capacity of their photobionts. An attempt is made to introduce an economic analysis of lichen growth processes, a view that has often been adopted in studies of higher plants. Areas in which more data are needed for the construction of a model on ' lichen resource allocation patterns ' are discussed.

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Section: Light and Nitrogen Relationsmentioning

confidence: 99%

Tansley Review No. 117

Palmqvist

2000

New Phytologist

218

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“…Plant cell walls (PCWs) are the most abundant renewable source of carbohydrates on Earth (Duchesne and Larson 1989). PCWs are sophisticated assemblies of cellulose, hemicellulose, pectin and glycoproteins.…”

Section: Introductionmentioning

confidence: 99%

Structural factors affecting 13C NMR chemical shifts of cellulose: a computational study

et al. 2017

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The doublet C4 peaks at * 85 and * 89 ppm in solid-state 13 C NMR spectra of native cellulose have been attributed to signals of C4 atoms on the surface (solvent-exposed) and in the interior of microfibrils, designated as sC4 and iC4, respectively. The relative intensity ratios of sC4 and iC4 observed in NMR spectra of cellulose have been used to estimate the degree of crystallinity of cellulose and the number of glucan chains in cellulose microfibrils. However, the molecular structures of cellulose responsible for the specific surface and interior C4 peaks have not been positively confirmed. Using density functional theory (DFT) methods and structures produced from classical molecular dynamics simulations, we investigated how the following four factors affect 13 C NMR chemical shifts in cellulose: conformations of exocyclic groups at C6 (tg, gt and gg), H 2 O molecules H-bonded on the surface of the microfibril, glycosidic bond angles (U, W) and the distances between H4 and HO3 atoms. We focus on changes in the d 13 C4 value because it is the most significant observable for the same C atom within the cellulose structure. DFT results indicate that different conformations of the exocyclic groups at C6 have the greatest influence on d 13 C4 peak separation, while the other three factors have secondary effects that increase the spread of the calculated C4 interior and surface peaks.

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“…amount, 70% is estimated to represent plant cell walls (Duchesne and Larson, 1989;Poorter and Villar, 1997). Humans use these wall materials mainly in the form of wood for heat production (Table 2), and as a building material (timber), in the pulp and paper industry (Fenning and Gershenzon, 2002), and as raw material in the textile industry, e.g.…”

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confidence: 99%

Cell‐wall carbohydrates and their modification as a resource for biofuels

Pauly¹,

Keegstra²

2008

The Plant Journal

724

510

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SummaryPlant cell walls represent the most abundant renewable resource on this planet. Despite their great abundance, only 2% of this resource is currently used by humans. Hence, research into the feasibility of using plant cell walls in the production of cost-effective biofuels is desirable. The main bottleneck for using wall materials is the recalcitrance of walls to efficient degradation into fermentable sugars. Manipulation of the wall polysaccharide biosynthetic machinery or addition of wall structure-altering agents should make it possible to tailor wall composition and architecture to enhance sugar yields upon wall digestion for biofuel fermentation. Study of the biosynthetic machinery and its regulation is still in its infancy and represents a major scientific and technical research challenge. Of course, any change in wall structure to accommodate cost-efficient biofuel production may have detrimental effects on plant growth and development due to the diverse roles of walls in the life of a plant. However, the diversity and abundance of wall structures present in the plant kingdom gives hope that this challenge can be met.

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Cellulose and the Evolution of Plant Life

Cited by 86 publications

References 19 publications

Tansley Review No. 117

Tansley Review No. 117

Structural factors affecting 13C NMR chemical shifts of cellulose: a computational study

Cell‐wall carbohydrates and their modification as a resource for biofuels

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