Abstract
Changes of specific soluble carbohydrates, nitrate reductase activity (NRA), and nitrate levels were monitored under prolonged darkness in MM.106 apple leaves (Malus dom- estica Borkh.). The prolonged darkness significantly reduced the level of total soluble carbohydrates, mainly due to the decrease in sorbitol. The prolonged darkness also greatly reduced NRA and consequently resulted in the accumulation of nitrate. The NRA correlated well with nitrate, total soluble carbohydrates, and sorbitol. The addition of 100 mM sorbitol, glucose or 50 mM sucrose to the in vivo nitrate reductase (NR) assay medium significantly increased the NRA of dark-pretreated leaves by 30 to 39%. These observations are consistent with the hypothesis that soluble carbohydrates produced photosyn- thetically provide the reductant and carbon skeletons required for the reduction of nitrate. However, the rate of decrease in NRA was much greater than that of decrease in the level of soluble carbohydrates and the NRA of dark pretreated leaves was not fully recovered to the level of the leaves, which had been subjected to 16 h light and 8 h dark, by the addition of soluble carbohydrates to the in vivo NR assay medium. It thus appears that there are other possible factors, in addition to the soluble carbohydrates, responsible for the decrease in NRA under the prolonged darkness.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 8
Claim · model-written summary
Prolonged darkness significantly reduced total soluble carbohydrates in apple leaves, mainly due to decreased sorbitol.
- Taxon
- apple
Malus domesticae0 - Material
- MM.106e0
- Treatment
- prolonged darknesse1
- Outcome
- total soluble carbohydratese1
- Direction
- reducede1
- Qualifier
- mainly due to the decrease in sorbitole1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“monitored under prolonged darkness in MM.106 apple leaves”
e1“The prolonged darkness significantly reduced the level of total soluble carbohydrates, mainly due to the decrease in sorbitol”
Claim · model-written summary
Prolonged darkness greatly reduced nitrate reductase activity in apple leaves.
- Taxon
- appleMalus domesticae0
- Treatment
- prolonged darknesse2
- Outcome
- NRAe2
- Direction
- reducede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“monitored under prolonged darkness in MM.106 apple leaves”
e2“The prolonged darkness also greatly reduced NRA and consequently resulted in the accumulation of nitrate”
Claim · model-written summary
Prolonged darkness resulted in accumulation of nitrate in apple leaves.
- Taxon
- appleMalus domesticae0
- Treatment
- prolonged darknesse2
- Compound
- nitratee2
- Outcome
- accumulation of nitratee2
- Direction
- increaseinferrede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“monitored under prolonged darkness in MM.106 apple leaves”
e2“The prolonged darkness also greatly reduced NRA and consequently resulted in the accumulation of nitrate”
Claim · model-written summary
Nitrate reductase activity correlated well with nitrate, total soluble carbohydrates and sorbitol in apple leaves.
- Taxon
- appleMalus domesticae0
- Compound
- nitratee4
- Outcome
- NRAe4
- Qualifier
- correlated well with nitrate, total soluble carbohydrates, and sorbitole4
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“monitored under prolonged darkness in MM.106 apple leaves”
e4“The NRA correlated well with nitrate, total soluble carbohydrates, and sorbitol”
Claim · model-written summary
Adding 100 mM sorbitol, glucose or 50 mM sucrose significantly increased nitrate reductase activity of dark-pretreated apple leaves by 30 to 39%.
- Taxon
- appleMalus domesticae0
- Treatment
- addition of 100 mM sorbitol, glucose or 50 mM sucrosee3
- Outcome
- NRAe3
- Direction
- increasede3
- Value
- 30 to 39%e3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“monitored under prolonged darkness in MM.106 apple leaves”
e3“The addition of 100 mM sorbitol, glucose or 50 mM sucrose to the in vivo nitrate reductase (NR) assay medium significantly increased the NRA of dark-pretreated leaves by 30 to 39%”
Claim · model-written summary
The rate of decrease in nitrate reductase activity under prolonged darkness was much greater than the rate of decrease in soluble carbohydrates.
- Taxon
- appleMalus domesticae0
- Outcome
- rate of decrease in NRAe5
- Qualifier
- much greater than that of decrease in the level of soluble carbohydratese5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“monitored under prolonged darkness in MM.106 apple leaves”
e5“the rate of decrease in NRA was much greater than that of decrease in the level of soluble carbohydrates”
Claim · model-written summary
Adding soluble carbohydrates did not fully restore nitrate reductase activity of dark-pretreated apple leaves to the level of leaves under 16 h light and 8 h dark.
- Taxon
- appleMalus domesticae0
- Treatment
- addition of soluble carbohydratese6
- Outcome
- NRAe6
- Direction
- not fully recoverede6
- Comparator
- 16 h light and 8 h darke6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“monitored under prolonged darkness in MM.106 apple leaves”
e6“the NRA of dark pretreated leaves was not fully recovered to the level of the leaves, which had been subjected to 16 h light and 8 h dark, by the addition of soluble carbohydrates to the in vivo NR assay medium”
Claim · model-written summary
Factors other than soluble carbohydrates appear to be responsible for the decrease in nitrate reductase activity under prolonged darkness in apple leaves.
- Taxon
- appleMalus domesticae0
- Outcome
- decrease in NRAe7
- Qualifier
- other possible factors, in addition to the soluble carbohydratese7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“monitored under prolonged darkness in MM.106 apple leaves”
e7“It thus appears that there are other possible factors, in addition to the soluble carbohydrates, responsible for the decrease in NRA under the prolonged darkness”
The same questions in other papers
sucrose · physiology: enzyme activity · Malus domestica (apple)Results agree
1 paper in the same direction as this paper
- positive
light · nutrient: content · Malus domestica (apple)Results agree
2 papers in the same direction as this paper
- negative
- negative
light · quality: sugar starch · Malus domestica (apple)Results agree
2 papers in the same direction as this paper
- negative
- no effect
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.