Maize composition

H. J. Miller, G. Henken, and J. A. Van Veen. Variation and composition of bacterial populations in the rhizosphere of maize, wheat and grass cultivars, Canadian Journal of Microbiology 35 656 (1989). 

A. Chaboud and M. Rougier, Effect of root density in incubation medium on root exudate composition of axenic maize seedlings, J. Plant Physiol. 131 602 (1991). 

Marita, J. M. Vermerris, W. Ralph, J. Hatheld, R. D. Variations in the cell wall composition of maize brown midrib mutants.. /. Agric. Food Chem. 2003, 51, 1313-1321. 

Figure 14.12 Trends through time in the bulk stable isotope values of collagen (6I3C and 815N), apatite ( 13C) and compound specific 813C values of cholesterol recorded from a number of individuals from the Illinois River Valley, USA, showing contiguous fluctuations in carbon stable isotope composition consistent with differing contributions of maize to the diet (Jim, Ambrose and Evershed unpublished data)...

Certainly, calculation of the metabolic quotient can reveal trends very different from those of basal respiration. As shown in Fig. 1, for the 7 land uses, trends in basal respiration were broadly similar to those for microbial biomass C and organic C. However, when the metabolic quotient was calculated, trends with land use were very different. Values were greater under sugarcane, maize and to a lesser extent annual ryegrass, than the other treatments. This suggests that the microbial community under these arable land uses is under more stress and/or has a different composition to that under the others. The most likely microbial stress under these land uses is likely to be a shortage of available substrate C. 

Figure 8.9 Carbon isotope composition of human bone collagen from the lower Illinois Valley, North America. The increase from <513C = —22%0 to —10%o at c. AD 1000 marks the arrival of maize agriculture at the end of the Late Woodland period (van der Merwe 1982). Reproduced by permission of American Scientist.

Secondly, a biosynthetic investigation on lignin variation was undertaken using maize internodes. Maize internodes were examined in this study since (a) fewer plants were required for analysis (greater biomass) and (b) possible variations between normal and b.m-mutants (21) could be studied. Lignin contents and monomer composition were compared between internodes, both being collected at the top and the bottom of the maize stem. These plant parts were chosen because of differences in the digestibility of different internodes as documented for Timothy (Phleum pratense)... 

Lignification of Maize Internodes. Lignin variability in maize was studied by comparison of the lignin contents and monomeric composition of its internodes. 

Table IV. Monomeric Composition of Lignin in the Parietal Residue (PR) of the Upper and Lower Internode from Stem or Normal and b.m.-Mutant of Maize shown by Thioacidolysis (G = guaiacyl and S =syringyl-trithio-ethylethers Fig. 1). (Yields are expressed as micromoles per gram of ABL in each sample of PR standard deviation less than 10% )...

Comparison of qualitative and quantitative data on lignification of the upper and the lower internodes of maize stems shown in Tables III to V, indicated only weak quantitative differences in lignin contents. However, there were significant differences in lignin monomeric composition and reactivity (delignification) between internodes in the maize stalk. 

So, clustering techniques have been used for classification. Piepponen et al. applied a hierarchical cluster analysis (CLUSTAN) to the classification of food oils (groundnut, soya, sunflower and maize) by their fatty acid composition. The dendrogram of the distances shows four weU-separated clusters. Some suspect commercial samples of sunflower oil fall near the cluster of soya oils, so far from the clainud class that they cannot be consider i genuine. 

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