Abstract
Excised primary leaf blades of barley (Hordeum vulgare L. cv Gerbel) rapidly synthesized large quantities of fructan in the light and, upon transfer to the dark, they rapidly degraded it again. In the course of such a light/dark cycle the activities of sucrose-sucrose-fructosyltransferase (SST), fructan hydrolase, and invertase were measured in cell-free extracts of the blades. SST activity increased 20-fold within 24 hours in the light and disappeared again upon transfer to the dark during a similar period of time. Cycloheximide inhibited the increase of SST activity in the light indicating de novo synthesis. The loss of SST activity in the dark, however, was unaffected by cycloheximide. No SST activity appeared in the light if photosynthesis was inhibited by lowering the CO(2) concentration in the atmosphere. However, SST activity and fructan synthesis were induced even in the dark and at a low CO(2) concentration when the leaf blades were immersed in a solution of sucrose. Several other sugars, maltose and fructose in particular, had the same effect. Trehalose induced SST activity but no fructan synthesis occurred. The activities of fructan hydrolase and invertase changed little during the light/dark cycle. It is suggested that the control of SST activity in conjunction with the supply of photosynthates plays a key role in the regulation of fructan metabolism.
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Claims 13
Claim · model-written summary
SST activity in excised barley leaf blades increased 20-fold within 24 hours in the light.
- Taxon
- Hordeum vulgare
.jpg?width=60)
Hordeum vulgaret0 - Material
- cv Gerbelt0
- Organ / stage
- Excised primary leaf bladese1
- Treatment
- lighte2
- Gene
- sucrose-sucrose-fructosyltransferasee3
- Outcome
- SST activitye2
- Direction
- increasede2
- Value
- 20-folde2
- Comparator
- darke2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
t0“Regulation of Fructan Metabolism in Leaves of Barley (Hordeum vulgare L. cv Gerbel)”
e1“Excised primary leaf blades of barley (Hordeum vulgare L. cv Gerbel) rapidly synthesized large quantities of fructan in the light”
e2“SST activity increased 20-fold within 24 hours in the light and disappeared again upon transfer to the dark”
e3“sucrose-sucrose-fructosyltransferase (SST)”
Claim · model-written summary
SST activity in barley leaf blades disappeared after transfer to the dark.
- Taxon
- Hordeum vulgareHordeum vulgaret0
- Organ / stage
- Excised primary leaf bladese1
- Treatment
- transfer to the darke2
- Outcome
- SST activitye2
- Direction
- disappearede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Regulation of Fructan Metabolism in Leaves of Barley (Hordeum vulgare L. cv Gerbel)”
e1“Excised primary leaf blades of barley (Hordeum vulgare L. cv Gerbel) rapidly synthesized large quantities of fructan in the light”
e2“SST activity increased 20-fold within 24 hours in the light and disappeared again upon transfer to the dark”
Claim · model-written summary
Cycloheximide inhibited the light-induced increase in SST activity, indicating de novo synthesis.
- Taxon
- Hordeum vulgareHordeum vulgaret0
- Treatment
- Cycloheximidee3
- Outcome
- the increase of SST activity in the lighte3
- Direction
- inhibitede3
- Qualifier
- indicating de novo synthesise3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Regulation of Fructan Metabolism in Leaves of Barley (Hordeum vulgare L. cv Gerbel)”
e3“Cycloheximide inhibited the increase of SST activity in the light indicating de novo synthesis”
Claim · model-written summary
Cycloheximide did not affect the loss of SST activity in the dark.
- Taxon
- Hordeum vulgareHordeum vulgaret0
- Treatment
- cycloheximidee4
- Outcome
- The loss of SST activity in the darke4
- Direction
- unaffectede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Regulation of Fructan Metabolism in Leaves of Barley (Hordeum vulgare L. cv Gerbel)”
e4“The loss of SST activity in the dark, however, was unaffected by cycloheximide”
Claim · model-written summary
No SST activity appeared in the light when photosynthesis was inhibited by lowering CO2.
- Taxon
- Hordeum vulgareHordeum vulgaret0
- Treatment
- lowering the CO(2) concentratione5
- Outcome
- SST activitye5
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Regulation of Fructan Metabolism in Leaves of Barley (Hordeum vulgare L. cv Gerbel)”
e5“No SST activity appeared in the light if photosynthesis was inhibited by lowering the CO(2) concentration in the atmosphere”
Claim · model-written summary
Sucrose induced SST activity and fructan synthesis in the dark and at low CO2.
- Taxon
- Hordeum vulgareHordeum vulgaret0
- Treatment
- a solution of sucrosee6
- Outcome
- SST activity and fructan synthesise6
- Direction
- inducede6
- Comparator
- in the dark and at a low CO(2) concentratione6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Regulation of Fructan Metabolism in Leaves of Barley (Hordeum vulgare L. cv Gerbel)”
e6“SST activity and fructan synthesis were induced even in the dark and at a low CO(2) concentration when the leaf blades were immersed in a solution of sucrose”
Claim · model-written summary
Maltose and fructose had the same effect as sucrose on SST activity and fructan synthesis.
- Taxon
- Hordeum vulgareHordeum vulgaret0
- Treatment
- maltose and fructosee7
- Outcome
- SST activity and fructan synthesise6
- Direction
- had the same effecte7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Regulation of Fructan Metabolism in Leaves of Barley (Hordeum vulgare L. cv Gerbel)”
e6“SST activity and fructan synthesis were induced even in the dark and at a low CO(2) concentration when the leaf blades were immersed in a solution of sucrose”
e7“Several other sugars, maltose and fructose in particular, had the same effect”
Claim · model-written summary
Trehalose induced SST activity in barley leaf blades.
- Taxon
- Hordeum vulgareHordeum vulgaret0
- Treatment
- Trehalosee1
- Outcome
- SST activitye1
- Direction
- inducede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Regulation of Fructan Metabolism in Leaves of Barley (Hordeum vulgare L. cv Gerbel)”
e1“Trehalose induced SST activity but no fructan synthesis occurred”
Claim · model-written summary
Trehalose did not lead to fructan synthesis.
- Taxon
- Hordeum vulgareHordeum vulgaret0
- Treatment
- Trehalosee1
- Outcome
- fructan synthesise1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Regulation of Fructan Metabolism in Leaves of Barley (Hordeum vulgare L. cv Gerbel)”
e1“Trehalose induced SST activity but no fructan synthesis occurred”
Claim · model-written summary
Fructan hydrolase and invertase activities changed little during the light/dark cycle.
- Taxon
- Hordeum vulgareHordeum vulgaret0
- Treatment
- light/dark cyclee1
- Outcome
- The activities of fructan hydrolase and invertasee1
- Direction
- changed littlee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Regulation of Fructan Metabolism in Leaves of Barley (Hordeum vulgare L. cv Gerbel)”
e1“The activities of fructan hydrolase and invertase changed little during the light/dark cycle”
Claim · model-written summary
Fructan was degraded in barley leaf blades after transfer to the dark.
- Taxon
- Hordeum vulgareHordeum vulgaret0
- Organ / stage
- Excised primary leaf bladese1
- Outcome
- fructane1
- Direction
- degradede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Regulation of Fructan Metabolism in Leaves of Barley (Hordeum vulgare L. cv Gerbel)”
e1“Excised primary leaf blades of barley (Hordeum vulgare L. cv Gerbel) rapidly synthesized large quantities of fructan in the light and, upon transfer to the dark, they rapidly degraded it again”
Claim · model-written summary
Barley leaf blades rapidly synthesized large quantities of fructan in the light.
- Taxon
- Hordeum vulgareHordeum vulgaret0
- Organ / stage
- Excised primary leaf bladese1
- Outcome
- fructane1
- Direction
- synthesizede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Regulation of Fructan Metabolism in Leaves of Barley (Hordeum vulgare L. cv Gerbel)”
e1“Excised primary leaf blades of barley (Hordeum vulgare L. cv Gerbel) rapidly synthesized large quantities of fructan in the light”
Claim · model-written summary
Control of SST activity together with photosynthate supply appears to regulate fructan metabolism in barley leaves.
- Taxon
- Hordeum vulgareHordeum vulgaret0
- Outcome
- regulation of fructan metabolisme1
- Qualifier
- the control of SST activity in conjunction with the supply of photosynthatese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Regulation of Fructan Metabolism in Leaves of Barley (Hordeum vulgare L. cv Gerbel)”
e1“It is suggested that the control of SST activity in conjunction with the supply of photosynthates plays a key role in the regulation of fructan metabolism”
The same questions in other papers
light · molecular: metabolites · Hordeum vulgare (barley)Positive and negative results
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