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| Web URL(s): | http://www.jstor.org/stable/2557531
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| Publication Type:
| Refereed |
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| Author(s): | Collis, B. E.;
Pollock, C. J. |
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| Author Affiliation: | Department of Botany, University of Glasgow; Environmental Biology Department, AFRC Institute of Grassland and Environmental Research, Welsh Plant Breeding Station, Aberystwyth |
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| Title: | The control of sucrose synthesis in leaves of Lolium temulentum L., a fructan-accumulating grass |
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| Source: | New Phytologist. Vol. 119, No. 4, December 1991, p. 483-489. |
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| Publishing Information: | Oxford, England: Cambridge University Press. |
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| Keywords: | TIC Keywords: Lolium temulentum; Sucrose; Leaves; Fructose; Grasses; Fructans
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| Abstract/Contents: | The control of sucrose synthesis was studied in leaves of the fructan-accumulating species Lolium temulentum L. The cytoplasmic fructose-1,6-bisphosphate (Cyt'F-1,6-BPase) was partially purified and its kinetic properties compared with the reported values for the enzyme from spinach leaves. The enzymes from the two species were similar, particularly in their inhibition by fructose-1,6-bisphosphate (F-2,6BP). Leaves were excised and illuminated or whole plants were chilled and illuminated in order to increase the accumulation of sucrose and low-molecular-weight fructan. Leaf glucose-6-phosphate (G-6-P) and fructose-6-phosphate (F-6-P) contents were estimated. The G-6-P/F-6-P ratio showed that most of the hexose phosphates were present in the cytoplasm. In excised leaves G-6-P concentrations were higher than controls after 4 h of illumination, probably reflecting the release of glucose by fructan synthesis. This extra source of substrate supply may disrupt the coordinated control of sucrose phosphate synthase (SPS) and Cyt'F-1,6-BPase. The calculated activity of Cyt'F-1,6-BPase in vivo is insufficient to catalyse the observed flux of photoassimilates to sucrose and fructan. The maximum catalytic activity of phosphofructophosphotransferase (PFP) was determined, and was found to be 12-14 u[mu]mol hexose g-1 f. wt h-1 in control leaves. It is proposed that, given suitable metabolite concentrations, PFP could supplement the inhibited Cyt'F-1,6-BPase activity and contribute to the flux of photoassimilates to sucrose and fructan. |
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| Language: | English |
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| References: | 30 |
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| Note: | Tables
Graphs |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Collis, B. E., and C. J. Pollock. 1991. The control of sucrose synthesis in leaves of Lolium temulentum L., a fructan-accumulating grass. New Phytol. 119(4):p. 483-489. |
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| Web URL(s):
http://www.jstor.org/stable/2557531
Last checked: 12/18/2015
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Access conditions: Item is within a limited-access website |
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MSU catalog number: QK 1 .N38 |
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