Abstract
The effect of nitrogen supply to chicory plants on carbon partitioning between shoot, root and tuberized root was studied at different stages of vegetative growth, using long-term 13CO2 labelling-chase experiments. This approach was complemented by measurement of storage carbohydrates and activities of enzymes involved in root sucrose metabolism (sucrose-sucrose fructosyl transferase (SST), sucrose synthase, invertase). In both young and mature plants, low NO3- resulted in a 30–35% decrease in 13C assimilation. However, the partitioning of 13C between shoot and root was affected differently at different stages of development. In young plants, in which carbohydrates were being used for structural root and shoot growth, neither 13C shoot/13C root ratio nor root activities of the above enzymes were modified by NO3- supply. In contrast, in mature plants storing large amounts of carbohydrates as fructan in the tuberized root, low NO3- caused the ratio to decrease from 0.6 to 0.2, despite unchanged net flux of 13C from shoot to root. The extractable activity of SST was elevated in mature plants, compared to young plants, at both low and high NO3-, consistent with its role in fructan synthesis. However, mature plants grown at low NO3- exhibited SST activity double that of plants grown at high NO3-. From these results, it is concluded that the observed decrease in shoot/root dry weight ratio at low NO3- supply is caused by increased utilization of carbohydrates for storage due to elevated root SST activity.
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Claims 7
Claim · model-written summary
Low nitrate decreased carbon assimilation by 30–35% in young and mature chicory.
- Taxon
- chicory
Cichorium intybust0 - Treatment
- low NO3-e0
- Outcome
- 13C assimilatione0
- Direction
- decreasee0
- Value
- 30–35%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“chicory (Cichorium intybus)”
e0“In both young and mature plants, low NO3- resulted in a 30–35% decrease in 13C assimilation.”
Claim · model-written summary
In young plants, nitrate supply did not modify the shoot/root carbon ratio or root enzyme activities.
- Taxon
- chicoryCichorium intybust0
- Treatment
- NO3- supplye0
- Outcome
- 13C shoot/13C root ratio nor root activities of the above enzymese0
- Direction
- neithere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“chicory (Cichorium intybus)”
e0“In young plants, in which carbohydrates were being used for structural root and shoot growth, neither 13C shoot/13C root ratio nor root activities of the above enzymes were modified by NO3- supply.”
Claim · model-written summary
In mature plants, low nitrate decreased the shoot/root carbon ratio from 0.6 to 0.2.
- Taxon
- chicoryCichorium intybust0
- Treatment
- low NO3-e0
- Outcome
- ratioe0
- Direction
- decreasee0
- Value
- 0.6 to 0.2e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“chicory (Cichorium intybus)”
e0“low NO3- caused the ratio to decrease from 0.6 to 0.2”
Claim · model-written summary
The net carbon flux from shoot to root remained unchanged in mature plants under low nitrate.
- Taxon
- chicoryCichorium intybust0
- Treatment
- low NO3-e1
- Outcome
- net flux of 13C from shoot to roote0
- Direction
- unchangede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“chicory (Cichorium intybus)”
e0“despite unchanged net flux of 13C from shoot to root”
e1“In both young and mature plants, low NO3- resulted in a 30–35% decrease in 13C assimilation.”
Claim · model-written summary
Mature plants had greater SST activity than young plants at both nitrate levels.
- Taxon
- chicoryCichorium intybust0
- Gene
- SSTe0
- Outcome
- extractable activity of SSTe0
- Direction
- elevatede0
- Comparator
- young plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“chicory (Cichorium intybus)”
e0“The extractable activity of SST was elevated in mature plants, compared to young plants, at both low and high NO3-”
Claim · model-written summary
Mature low nitrate plants had twice the SST activity of mature high nitrate plants.
- Taxon
- chicoryCichorium intybust0
- Treatment
- low NO3-e0
- Gene
- SSTe0
- Outcome
- SST activitye0
- Direction
- doublee0
- Comparator
- high NO3-e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“chicory (Cichorium intybus)”
e0“mature plants grown at low NO3- exhibited SST activity double that of plants grown at high NO3-”
Claim · model-written summary
Authors attributed the lower shoot/root dry weight ratio at low nitrate to greater carbohydrate storage from elevated root SST activity.
- Taxon
- chicoryCichorium intybust0
- Gene
- SSTe0
- Outcome
- shoot/root dry weight ratioe0
- Direction
- decreasee0
- Qualifier
- increased utilization of carbohydrates for storagee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“chicory (Cichorium intybus)”
e0“the observed decrease in shoot/root dry weight ratio at low NO3- supply is caused by increased utilization of carbohydrates for storage due to elevated root SST activity”