Abstract
Nonstructural carbohydrate status and activities of ADP‐glucose pyrophosphorylase (EC 2.7.7.27, ADPG pyrophosphorylase) and sucrose phosphate synthase (EC 2.4.1.14, SPS) were determined during ageing of tobacco ( Nicotiana tabacum L., cvs KY 14 and Speight G28) leaves sampled from control plants and from plants that had the apical meristem and subsequent axillary growth removed (detopped plants). Over the 30‐day period shoot growth increased much more for control compared to detopped plants, but the increase in root growth was similar for both treatments. Dry matter and leaf area of the individual leaf used for enzyme and metabolite analysis were constant over time for controls but increased 5‐fold for detopped plants. Ageing of control leaves was indicated by a progressive loss of chlorophyll and ribulose 1, 5‐bisphosphate carboxylase (EC 4.1.1.39, Rubisco) activity; loss of these components was diminished for detopped plants. In contrast to chlorophyll and Rubisco activity, activities of ADPG pyrophosphorylase and SPS remained relatively constant over time for controls. Thus, under normal ageing conditions, changes in activities of ADPG pyrophosphorylase and SPS were not closely associated with changes in the standard senescence indicators chlorophyll and Rubisco activity. The activities of ADPG pyrophosphorylase and SPS were enhanced, relative to controls, within 6 days after applying the detopping treatment and activities remained high for the duration of the 30‐day period. Detopping also led to increased concentrations of starch and sucrose, but the increases were not well correlated with changes in enzyme activities. The data indicated that the leaves of detopped plants functioned as both source leaves, with enhanced ability to synthesize carbohydrate, and sink leaves, with enhanced growth. Therefore, activities of ADPG pyrophosphorylase and SPS were more responsive to changes within an individual leaf than to changes in whole plant growth.
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Claims 11
Claim · model-written summary
Shoot growth increased more in controls than detopped plants.
- Taxon
- tobacco
Nicotiana tabacume1 - Treatment
- detopped plantse0
- Outcome
- shoot growthe0
- Direction
- increased much more for controle0
- Comparator
- controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“shoot growth increased much more for control compared to detopped plants”
e1“ageing of tobacco”
Claim · model-written summary
Root growth increased similarly in controls and detopped plants.
- Taxon
- tobaccoNicotiana tabacume2
- Treatment
- detopped plantse1
- Outcome
- root growthe0
- Direction
- similare0
- Comparator
- controle1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the increase in root growth was similar for both treatments”
e1“control compared to detopped plants”
e2“ageing of tobacco”
Claim · model-written summary
Leaf dry matter and area remained constant in controls but rose fivefold after detopping.
- Taxon
- tobaccoNicotiana tabacume1
- Organ / stage
- leafe0
- Treatment
- detopped plantse0
- Outcome
- Dry matter and leaf areae0
- Direction
- increasede0
- Value
- 5‐folde0
- Comparator
- controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Dry matter and leaf area of the individual leaf used for enzyme and metabolite analysis were constant over time for controls but increased 5‐fold for detopped plants”
e1“ageing of tobacco”
Claim · model-written summary
Control leaves progressively lost chlorophyll and Rubisco activity with age.
- Taxon
- tobaccoNicotiana tabacume1
- Organ / stage
- leavese0
- Outcome
- chlorophyll and ribulose 1, 5‐bisphosphate carboxylase (EC 4.1.1.39, Rubisco) activitye0
- Direction
- progressive losse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ageing of control leaves was indicated by a progressive loss of chlorophyll and ribulose 1, 5‐bisphosphate carboxylase (EC 4.1.1.39, Rubisco) activity”
e1“ageing of tobacco”
Claim · model-written summary
Detopping diminished the age-related loss of chlorophyll and Rubisco activity.
- Taxon
- tobaccoNicotiana tabacume2
- Treatment
- detopped plantse0
- Outcome
- chlorophyll and ribulose 1, 5‐bisphosphate carboxylase (EC 4.1.1.39, Rubisco) activitye1
- Direction
- diminishede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“loss of these components was diminished for detopped plants”
e1“a progressive loss of chlorophyll and ribulose 1, 5‐bisphosphate carboxylase (EC 4.1.1.39, Rubisco) activity”
e2“ageing of tobacco”
Claim · model-written summary
ADPG pyrophosphorylase and SPS activities remained relatively constant over time in controls.
- Taxon
- tobaccoNicotiana tabacume1
- Gene
- ADPG pyrophosphorylase and SPSe0
- Outcome
- activities of ADPG pyrophosphorylase and SPSe0
- Direction
- remained relatively constante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“activities of ADPG pyrophosphorylase and SPS remained relatively constant over time for controls”
e1“ageing of tobacco”
Claim · model-written summary
ADPG pyrophosphorylase and SPS activities rose within six days of detopping and remained high for 30 days.
- Taxon
- tobaccoNicotiana tabacume1
- Treatment
- detopping treatmente0
- Gene
- ADPG pyrophosphorylase and SPSe0
- Outcome
- activities of ADPG pyrophosphorylase and SPSe0
- Direction
- enhancede0
- Qualifier
- within 6 dayse0
- Comparator
- controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“activities of ADPG pyrophosphorylase and SPS were enhanced, relative to controls, within 6 days after applying the detopping treatment and activities remained high for the duration of the 30‐day period”
e1“ageing of tobacco”
Claim · model-written summary
Detopping increased starch and sucrose concentrations.
- Taxon
- tobaccoNicotiana tabacume1
- Treatment
- Detoppinge0
- Outcome
- concentrations of starch and sucrosee0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Detopping also led to increased concentrations of starch and sucrose”
e1“ageing of tobacco”
Claim · model-written summary
Carbohydrate increases did not correlate well with enzyme activity changes.
- Taxon
- tobaccoNicotiana tabacume2
- Outcome
- concentrations of starch and sucrosee1
- Direction
- not well correlatede0
- Comparator
- changes in enzyme activitiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the increases were not well correlated with changes in enzyme activities”
e1“increased concentrations of starch and sucrose”
e2“ageing of tobacco”
Claim · model-written summary
Detopped leaves had both source function with greater carbohydrate synthesis and sink function with greater growth.
- Taxon
- tobaccoNicotiana tabacume1
- Organ / stage
- leavese0
- Outcome
- enhanced ability to synthesize carbohydrate, and sink leaves, with enhanced growthe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the leaves of detopped plants functioned as both source leaves, with enhanced ability to synthesize carbohydrate, and sink leaves, with enhanced growth”
e1“ageing of tobacco”
Claim · model-written summary
ADPG pyrophosphorylase and SPS responded more to changes within leaves than to whole-plant growth.
- Taxon
- tobaccoNicotiana tabacume1
- Organ / stage
- individual leafe0
- Gene
- ADPG pyrophosphorylase and SPSe0
- Outcome
- activities of ADPG pyrophosphorylase and SPSe0
- Direction
- more responsivee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“activities of ADPG pyrophosphorylase and SPS were more responsive to changes within an individual leaf than to changes in whole plant growth”
e1“ageing of tobacco”
The same questions in other papers
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See all 7 papers →pruning · molecular: metabolites · Nicotiana tabacum (tobacco)Positive and negative results
22 papers in the same direction as this paper · 4 in the opposite direction
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See all 27 papers →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.