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| Web URL(s): | http://www.jstor.org/stable/2557534
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| Publication Type:
| Refereed |
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| Author(s): | Smouter, Henk;
Simpson, Richard J. |
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| Author Affiliation: | School of Agriculture and Forestry, University of Melbourne |
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| Title: | Synthesis of fructan |
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| Article Series: | Fructan metabolism in leaves of Lolium rigidum Gaudin, part 1 |
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| Source: | New Phytologist. Vol. 119, No. 4, December 1991, p. 509-516. |
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| Publishing Information: | Oxford, England: Cambridge University Press. |
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| # of Pages: | 8 |
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| Keywords: | TIC Keywords: Fructans; Metabolism; Leaves; Lolium rigidum; Carbohydrates; Sucrose
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| Abstract/Contents: | Accumulation of water-soluble carbohydrates (WSC) in leaves of intact seedlings of annual ryegrass (Lolium rigidum Gaudin cv. Wimmera) was studied using a novel model system. The roots and leaf bases of intact seedlings, grown in nutrient solution, were cooled to 5 C to reduce sink activity and the production of photosynthates was enhanced by continuous illumination of the plants. This resulted in accumulation of WSC in the shoots. Thin-layer chromatography showed the presence of a complex series of fructans, distinct from those found in tubers of Helianthus tuberous. Two trisaccharides, 1-kestose and neokestose, were present in various proportions, but no 6-kestose was detected in the shoots. After feeding 14CO2 to the seedlings in a pulse-chase experiment, high specific radioactivity was measured in monosaccharides, sucrose and fructan oligosaccharide fractions to DP 5 within 1 hr. These fructan pools were rapidly turned over without significant accumulation of fructans during the first 16 h of the accumulation phase. Neokestose and 1-kestose contained equally high specific radioactivity, 1 h after feeding. These results indicated that neokestose was possibly as important as 1-kestose as a possible precursor for synthesis of fructan. Concentrations of WSC increased linearly from 2 to 14 mg g-1 f. wt of the leaves after 16 h and reached a concentration of 30 mg g-1 f. wt after 64 h. Sucrose, glucose and fructose were the first sugars to be accumulated and reached concentrations of 10, 3.5 and 2.5 mg g-1 f. wt, respectively. Tri- and tetrasaccharide accumulated to measurable concentrations after approximately 16 h of treatment and reached concentrations of 2.5 and 2.0 mg g-1 f. wt, respectively. The appearance of these oligosaccharides occurred when sucrose and monosaccharides reached stable concentrations in the leaves. The WSC concentration declined at a rate of about 0.8 mg g-1 f. wt h-1, when the root temperature was raised to 24 C after 64 h and plants were darkened. The decline in WSC concentration was accompanied by a 70% decline in sucrose concentration and a decline in all other fructan concentrations, while the concentration of fructose increased 2-fold. |
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| Language: | English |
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| References: | 25 |
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| See Also: | See also part 2 "Fructosyltransferase, invertase and fructan hydrolase activity" New Phytologist, 119(4) December 1991, p. 517-526, R=22814. R=22814 |
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| Note: | Pictures, b/w
Tables
Graphs |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Smouter, H., and R. J. Simpson. 1991. Synthesis of fructan. New Phytol. 119(4):p. 509-516. |
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| Web URL(s):
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Last checked: 12/18/2015
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MSU catalog number: QK 1 .N38 |
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