Abstract
Starch synthesis in leaves was increased by phosphate starvation or by treatments which decreased cytoplasmic orthophosphate levels (such as mannose feeding). Usually less than 30% of the total carbon fixed during CO(2) assimilation was incorporated into starch in spinach (Spinacia oleracea L.), spinach beet (Beta vulgaris), and tobacco (Nicotiana tabacum) leaves.In isolated spinach chloroplasts, formation of starch from CO(2) was usually less than in leaves. In the absence of significant levels of 3-phosphoglycerate, concentrations of phosphate as low as 1 mm (in the medium) or 10 mm (in the stroma) almost completely inhibited starch synthesis. The inhibitory action of phosphate could be overcome by 3-phosphoglycerate. The controlling factor of starch synthesis appeared to be the ratio of phosphoglycerate to orthophosphate rather than the stromal hexose monophosphate concentration, and it is suggested that this control is exerted via the phosphate translocator and the known allosteric regulation of ADP-glucose pyrophosphorylase. Starch synthesis was also favored by the presence of dihydroxyacetone phosphate and by high light and high temperature. Oxygen was inhibitory, probably owing to carbon drain into glycolate. Starch formation by intact chloroplasts could not be promoted by added glucose or glucose 6-phosphate.Starch mobilization in the dark was promoted by orthophosphate and phosphate-dependent mobilization was inhibited by phosphoglycerate. The principal products of starch breakdown in the presence of phosphate were the transport metabolites dihydroxyacetone phosphate and 3-phosphoglycerate. Formation of these compounds from starch was stimulated by ATP or oxaloacetate. In a phosphate-independent reaction, starch was also converted to neutral products such as maltose and glucose. The rates of phosphate-dependent starch degradation phosphorolysis were very much higher than those of starch hydrolysis for which there was no phosphate requirement.
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Claims 20
Claim · model-written summary
Phosphate starvation or treatments lowering cytoplasmic orthophosphate increased leaf starch synthesis.
- Taxon
- spinach (Spinacia oleracea L.), spinach beet (Beta vulgaris), and tobacco (Nicotiana tabacum)
Spinacia oleracea
Nicotiana tabacum
Beta vulgarise1 - Treatment
- phosphate starvatione0
- Outcome
- Starch synthesis in leavese0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starch synthesis in leaves was increased by phosphate starvation or by treatments which decreased cytoplasmic orthophosphate levels (such as mannose feeding).”
e1“spinach (Spinacia oleracea L.), spinach beet (Beta vulgaris), and tobacco (Nicotiana tabacum) leaves”
Claim · model-written summary
Usually less than 30% of fixed carbon entered starch in spinach, spinach beet and tobacco leaves.
- Taxon
- spinach (Spinacia oleracea L.), spinach beet (Beta vulgaris), and tobacco (Nicotiana tabacum)Spinacia oleraceaNicotiana tabacumBeta vulgarise0
- Outcome
- total carbon fixed during CO(2) assimilation was incorporated into starche0
- Value
- less than 30%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Usually less than 30% of the total carbon fixed during CO(2) assimilation was incorporated into starch in spinach (Spinacia oleracea L.), spinach beet (Beta vulgaris), and tobacco (Nicotiana tabacum) leaves.”
Claim · model-written summary
Starch formation from CO2 in isolated spinach chloroplasts was usually less than in leaves.
- Taxon
- spinachSpinacia oleraceae0
- Organ / stage
- chloroplastse0
- Outcome
- formation of starch from CO(2)e0
- Direction
- less thane0
- Comparator
- leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In isolated spinach chloroplasts, formation of starch from CO(2) was usually less than in leaves.”
Claim · model-written summary
Low phosphate nearly completely inhibited starch synthesis without substantial 3-phosphoglycerate.
- Treatment
- phosphatee0
- Outcome
- starch synthesise0
- Direction
- inhibitede0
- Value
- 1 mme0
- Qualifier
- In the absence of significant levels of 3-phosphoglyceratee0
Not reportedTaxonComparator
Verbatim
e0“In the absence of significant levels of 3-phosphoglycerate, concentrations of phosphate as low as 1 mm (in the medium) or 10 mm (in the stroma) almost completely inhibited starch synthesis.”
t0“Leaves and Isolated Chloroplasts”
Claim · model-written summary
3-phosphoglycerate overcame phosphate inhibition of starch synthesis.
- Taxon
- spinachSpinacia oleraceae1
- Treatment
- 3-phosphoglyceratee0
- Outcome
- inhibitory action of phosphatee0
- Direction
- overcomee0
- Comparator
- phosphatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The inhibitory action of phosphate could be overcome by 3-phosphoglycerate.”
e1“isolated spinach chloroplasts”
Claim · model-written summary
The phosphoglycerate to orthophosphate ratio appeared to control starch synthesis rather than stromal hexose monophosphate.
- Taxon
- spinachSpinacia oleraceae1
- Compound
- phosphoglyceratee0
- Outcome
- starch synthesise0
- Qualifier
- ratio of phosphoglycerate to orthophosphatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The controlling factor of starch synthesis appeared to be the ratio of phosphoglycerate to orthophosphate rather than the stromal hexose monophosphate concentration”
e1“isolated spinach chloroplasts”
Claim · model-written summary
Control was suggested to operate through the phosphate translocator and ADP-glucose pyrophosphorylase regulation.
- Taxon
- spinachSpinacia oleraceae1
- Gene
- ADP-glucose pyrophosphorylasee0
- Outcome
- this controle0
- Qualifier
- phosphate translocatore0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it is suggested that this control is exerted via the phosphate translocator and the known allosteric regulation of ADP-glucose pyrophosphorylase”
e1“isolated spinach chloroplasts”
Claim · model-written summary
Dihydroxyacetone phosphate favored starch synthesis.
- Taxon
- spinachSpinacia oleraceae1
- Treatment
- dihydroxyacetone phosphatee0
- Outcome
- Starch synthesise0
- Direction
- favorede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starch synthesis was also favored by the presence of dihydroxyacetone phosphate and by high light and high temperature.”
e1“isolated spinach chloroplasts”
Claim · model-written summary
High light favored starch synthesis.
- Taxon
- spinachSpinacia oleraceae1
- Treatment
- high lighte0
- Outcome
- Starch synthesise0
- Direction
- favorede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starch synthesis was also favored by the presence of dihydroxyacetone phosphate and by high light and high temperature.”
e1“isolated spinach chloroplasts”
Claim · model-written summary
High temperature favored starch synthesis.
- Taxon
- spinachSpinacia oleraceae1
- Treatment
- high temperaturee0
- Outcome
- Starch synthesise0
- Direction
- favorede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starch synthesis was also favored by the presence of dihydroxyacetone phosphate and by high light and high temperature.”
e1“isolated spinach chloroplasts”
Claim · model-written summary
Oxygen inhibited starch synthesis, possibly through carbon drain into glycolate.
- Taxon
- spinachSpinacia oleraceae1
- Treatment
- Oxygene0
- Outcome
- inhibitorye0
- Direction
- inhibitorye0
- Qualifier
- probably owing to carbon drain into glycolatee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Oxygen was inhibitory, probably owing to carbon drain into glycolate.”
e1“isolated spinach chloroplasts”
Claim · model-written summary
Added glucose did not promote starch formation by intact chloroplasts.
- Taxon
- spinachSpinacia oleraceae1
- Treatment
- added glucosee0
- Outcome
- Starch formatione0
- Direction
- could not be promotede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starch formation by intact chloroplasts could not be promoted by added glucose or glucose 6-phosphate.”
e1“isolated spinach chloroplasts”
Claim · model-written summary
Added glucose 6-phosphate did not promote starch formation by intact chloroplasts.
- Taxon
- spinachSpinacia oleraceae1
- Treatment
- glucose 6-phosphatee0
- Outcome
- Starch formatione0
- Direction
- could not be promotede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starch formation by intact chloroplasts could not be promoted by added glucose or glucose 6-phosphate.”
e1“isolated spinach chloroplasts”
Claim · model-written summary
Orthophosphate promoted starch mobilization in the dark.
- Taxon
- spinachSpinacia oleraceae1
- Treatment
- orthophosphatee0
- Outcome
- Starch mobilizatione0
- Direction
- promotede0
- Qualifier
- in the darke0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starch mobilization in the dark was promoted by orthophosphate”
e1“isolated spinach chloroplasts”
Claim · model-written summary
Phosphoglycerate inhibited phosphate-dependent starch mobilization.
- Taxon
- spinachSpinacia oleraceae1
- Treatment
- phosphoglyceratee0
- Outcome
- phosphate-dependent mobilizatione0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“phosphate-dependent mobilization was inhibited by phosphoglycerate”
e1“isolated spinach chloroplasts”
Claim · model-written summary
Phosphate-dependent starch breakdown chiefly produced dihydroxyacetone phosphate and 3-phosphoglycerate.
- Taxon
- spinachSpinacia oleraceae1
- Outcome
- transport metabolites dihydroxyacetone phosphate and 3-phosphoglyceratee0
- Qualifier
- in the presence of phosphatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The principal products of starch breakdown in the presence of phosphate were the transport metabolites dihydroxyacetone phosphate and 3-phosphoglycerate.”
e1“isolated spinach chloroplasts”
Claim · model-written summary
ATP stimulated formation of starch-breakdown transport metabolites.
- Taxon
- spinachSpinacia oleraceae2
- Treatment
- ATPe0
- Outcome
- dihydroxyacetone phosphate and 3-phosphoglyceratee1
- Direction
- stimulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Formation of these compounds from starch was stimulated by ATP or oxaloacetate.”
e1“The principal products of starch breakdown in the presence of phosphate were the transport metabolites dihydroxyacetone phosphate and 3-phosphoglycerate.”
e2“isolated spinach chloroplasts”
Claim · model-written summary
Oxaloacetate stimulated formation of starch-breakdown transport metabolites.
- Taxon
- spinachSpinacia oleraceae2
- Treatment
- oxaloacetatee0
- Outcome
- dihydroxyacetone phosphate and 3-phosphoglyceratee1
- Direction
- stimulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Formation of these compounds from starch was stimulated by ATP or oxaloacetate.”
e1“The principal products of starch breakdown in the presence of phosphate were the transport metabolites dihydroxyacetone phosphate and 3-phosphoglycerate.”
e2“isolated spinach chloroplasts”
Claim · model-written summary
Starch also converted to maltose and glucose through a phosphate-independent reaction.
- Taxon
- spinachSpinacia oleraceae1
- Outcome
- neutral products such as maltose and glucosee0
- Qualifier
- phosphate-independent reactione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In a phosphate-independent reaction, starch was also converted to neutral products such as maltose and glucose.”
e1“isolated spinach chloroplasts”
Claim · model-written summary
Phosphate-dependent phosphorolysis degraded starch much faster than starch hydrolysis.
- Taxon
- spinachSpinacia oleraceae1
- Outcome
- rates of phosphate-dependent starch degradation phosphorolysise0
- Direction
- very much highere0
- Comparator
- starch hydrolysise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The rates of phosphate-dependent starch degradation phosphorolysis were very much higher than those of starch hydrolysis for which there was no phosphate requirement.”
e1“isolated spinach chloroplasts”
The same questions in other papers
ATP · molecular: metabolites · Spinacia oleracea (spinach)Positive and negative results
1 paper in the same direction as this paper · 2 in the opposite direction
- no effect
- no effect
- positive
oxaloacetate(2-) · molecular: metabolites · Spinacia oleracea (spinach)Results agree
1 paper in the same direction as this paper
- positive
phosphorus · quality: sugar starch · Nicotiana tabacum (tobacco)Positive and negative results
3 in the opposite direction
This paper is about lacking the nutrient, so it counts the other way round here.
- positive
- positive
- positive
phosphorus · quality: sugar starch · Beta vulgaris (beet)Positive and negative results
3 papers in the same direction as this paper · 11 in the opposite direction
This paper is about lacking the nutrient, so it counts the other way round here.
- positive
- positive
- positive
11 papers more in this group
See all 15 papers →light · quality: sugar starch · Spinacia oleracea (spinach)Results agree
1 paper in the same direction as this paper
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.