Land plants

Most carbohydrates exist in the form of polysaccharides. Polysaccharides give stmcture to the cell walls of land plants (cellulose), seaweeds, and some microorganisms and store energy (starch in plants and glycogen in animals). They are important in the human diet and in many commercial apphcations. [Pg.473]

There is a great diversity of chemical stmctures in the polysaccharides of plant tissue. Table 1 fists some principal types of polysaccharides in edible land plants using simplified stmctures. Other reviews (6—8) provide a more complete description of the complex stmctures. Complete stmctures for many of the polysaccharides of edible sources have not yet been determined. [Pg.69]

The cycles of carbon and the other main plant nutrients are coupled in a fundamental way by the involvement of these elements in photosynthetic assimilation and plant growth. Redfield (1934) and several others have shown that there are approximately constant proportions of C, N, S, and P in marine plankton and land plants ("Redfield ratios") see Chapter 10. This implies that the exchange flux of one of these elements between the biota reservoir and the atmosphere - or ocean - must be strongly influenced by the flux of the others. [Pg.73]

How might chemical and physical weathering have differed from today s world before the advent of rooted land plants What about before any land plants, assuming that there were once green films ... [Pg.224]

Keeling, C. D. (1973a). The carbon dioxide cycle. Reservoir models to depict the exchange of atmospheric carbon dioxide with the oceans and land plants. In "Chemistry of the Lower Atmosphere" (S. Rasool, ed.), pp. 251-329. Plenum Press, New York. [Pg.314]

Computed from an estimate of the N in land biota (12 x 10 tons N Delwiche, 1970) and a mean P N atomic ratio in land plants (1.8 16 Deevey, 1970) Mackenzie et al. (1993)... [Pg.368]

Chlorophyll b 459,647 Land plants and Green -CH=CH2 -CHO -CH2CH3 -CHjCHjCOO-phytyl Double Single... [Pg.30]

Chlorophyll b occurs as an accessory pigment of the light-harvesting systems in land plants and green algae, and comprises one-third (or less) of total chlorophyll. The biosynthesis of chlorophyll b has been an area of active research particularly regarding its compartmentalization in chloroplast membranes, identification of the gene for chlorophyllide a oxidase, and characterization of the enzymes involved. ... [Pg.37]

Tan, Y.A., Low, K.S., and Chong, C.L., Rapid determination of chlorophylls in vegetable oils by laser-based fluorometry, J. Sci. Food Agric., 66, 479, 1994. Bhattacharya, D. and Medlin, L., Algal phylogeny and the origin of land plants, Plant Physiol., 116, 9, 1998. [Pg.46]

Chlorophylls a and b and, in smaller amounts, chlorophylls a and b can be found in any photosynthetic tissue obtained from land plants. They may thus be extracted from an almost infinite number of sources [23], although it is easier to work with material containing relatively litde water as this has to be removed at later stages of the workup. Thus, woodier tissues are to be preferred as sources as compared to those containing large volumes of water, e.g., parsley rather than cucumber. [Pg.335]

J. I. Sprent, F. R. Minchin, and R. Parson, Evolution since Knoxville were rhizobia wise to inhabit land plants New horizon. in nitrogen fixation (R. Palacios, J. Mora and W. E. Newton, eds.), Kluwer Academic Publishers, Dordrecht, 1993. [Pg.321]

The various chlorophyll types are listed in Table 12.1. An alternate resonance form is available for all the chlorophylls listed in Table 12.1 except for bacteriochlorophyll. Chlorophyll a is found in all green plants. In most land plants and algae one also finds chlorophyll b or d. Thus a more correct statement than the one made previously would be that chlorophyll a is the photochemically active pigment in all green plants, as shown by experimenta-tion.<8)... [Pg.283]

Edwards D, Abbott GD, Raven JA (1996) Cuticles of early land plants a palaeoecophy-siological evaluation. In Kerstiens G (ed) Plant cuticles an integrated functional approach. BIOS Scientific Publishers, Oxford UK, chap 1... [Pg.50]

Various primitive multi-cellular eukaryotes in precambrian fossils, some mineralized. Green algae dominant. Early land plants Fossils and tracks. Oxygen and ozone accumulating 1-4%... [Pg.278]

Natural products find a place not as such but at points where, once again, their chemistry illustrates the behavior of their furan nuclei. There are now so many naturally occurring furans (the sea adds its quota to the land plant count every week) that even to make a list, as in the previous review, was too big a task and would have taken too much room happily, reference to almost any issue of Phytochemistry will immediately supply examples and there are already some good lists available elsewhere (eremophilane2 and farnesane23 furans, butenolides,3 furanoid fatty acids,4 marine products5). [Pg.168]

Xylan occurs in practically all land plants and is said to be present in some marine algae.6 In both wide botanical distribution and abundance in nature it closely follows cellulose and starch. It is most abundant in annual crops, particularly in agricultural residues such as corn cobs, corn stalks, grain hulls and stems. Here it occurs in amounts ranging from 15 to 30%. Hard woods contain 20 to 25% xylan while soft woods contain 7 to 12 %. Spring wood has more pentosan than summer wood. 7 Low strength vegetable fibers of commerce such as jute, sisal, Manila... [Pg.283]

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