Abstract
Nitrate reductase (NR) induction is enhanced by exogenously supplied sucrose in excised pea roots exposed to both exogenous nitrate and exogenous nitrite. NR synthesis is preferentially supported by sugars transported to the cells at the moment, however NR induction can take place for some time without exogenous sugar influx if roots are saturated with sugars during precultivation. Steady high NR levels are dependent on steady sugar and nitrate influxes. NR induction is low in roots precultivated for 20 h without sucrose although sugar content is still high in them. This suggests that compartmentation of sugars in the cells is of major importance during NR induction. Total nitrate content in roots exposed to nitrate is not influenced by sucrose supplied together with nitrate. Some nitrite is oxidized to nitrate in roots exposed to exogenous nitrite ; we assume that this nitrate is responsible for NR induction. Our results indicate that sugars, besides many indirect effects on NR induction, may also directly influence NR synthesis either as coinducers or as derepressors of NR synthesis. Our results further show that NR is not a product-inducible enzyme.
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Claims 11
Claim · model-written summary
Sucrose enhanced nitrate reductase induction in excised pea roots exposed to nitrate and nitrite.
- Taxon
- pisum sativum
Lathyrus oleraceust0 - Organ / stage
- excised pea rootse0
- Treatment
- exogenously supplied sucrosee0
- Outcome
- Nitrate reductase (NR) inductione0
- Direction
- enhancede0
- Qualifier
- both exogenous nitrate and exogenous nitritee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“pisum sativum”
e0“Nitrate reductase (NR) induction is enhanced by exogenously supplied sucrose in excised pea roots exposed to both exogenous nitrate and exogenous nitrite.”
Claim · model-written summary
Sugar transport at the time of induction preferentially supported NR synthesis.
- Taxon
- pisum sativumLathyrus oleraceust0
- Compound
- sugarse0
- Outcome
- NR synthesise0
- Direction
- preferentially supportede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“pisum sativum”
e0“NR synthesis is preferentially supported by sugars transported to the cells at the moment”
Claim · model-written summary
NR induction persisted for some time without external sugar influx after sugar-saturated precultivation.
- Taxon
- pisum sativumLathyrus oleraceust0
- Outcome
- NR induction can take placee0
- Qualifier
- without exogenous sugar influx if roots are saturated with sugars during precultivatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“pisum sativum”
e0“NR induction can take place for some time without exogenous sugar influx if roots are saturated with sugars during precultivation”
Claim · model-written summary
Sustained high NR levels depended on sustained sugar and nitrate influx.
- Taxon
- pisum sativumLathyrus oleraceust0
- Compound
- sugar and nitratee0
- Outcome
- Steady high NR levelse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“pisum sativum”
e0“Steady high NR levels are dependent on steady sugar and nitrate influxes.”
Claim · model-written summary
NR induction was low after 20 hours of precultivation without sucrose despite high sugar content.
- Taxon
- pisum sativumLathyrus oleraceust0
- Outcome
- NR inductione0
- Direction
- lowe0
- Qualifier
- precultivated for 20 h without sucrose although sugar content is still highe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“pisum sativum”
e0“NR induction is low in roots precultivated for 20 h without sucrose although sugar content is still high in them.”
Claim · model-written summary
Sugar compartmentation was proposed as important for NR induction.
- Taxon
- pisum sativumLathyrus oleraceust0
- Outcome
- NR inductione0
- Qualifier
- compartmentation of sugars in the cellse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“pisum sativum”
e0“This suggests that compartmentation of sugars in the cells is of major importance during NR induction.”
Claim · model-written summary
Sucrose supplied with nitrate did not influence total nitrate content.
- Taxon
- pisum sativumLathyrus oleraceust0
- Treatment
- sucrose supplied together with nitratee0
- Outcome
- Total nitrate contente0
- Direction
- not influencede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“pisum sativum”
e0“Total nitrate content in roots exposed to nitrate is not influenced by sucrose supplied together with nitrate.”
Claim · model-written summary
Some exogenous nitrite was oxidized to nitrate in roots.
- Taxon
- pisum sativumLathyrus oleraceust0
- Outcome
- nitrite is oxidized to nitratee0
- Qualifier
- roots exposed to exogenous nitritee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“pisum sativum”
e0“Some nitrite is oxidized to nitrate in roots exposed to exogenous nitrite”
Claim · model-written summary
The authors assumed nitrate formed from nitrite was responsible for NR induction.
- Taxon
- pisum sativumLathyrus oleraceust0
- Compound
- nitratee0
- Outcome
- NR inductione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“pisum sativum”
e0“we assume that this nitrate is responsible for NR induction”
Claim · model-written summary
The authors proposed that sugars may directly affect NR synthesis as coinducers or derepressors.
- Taxon
- pisum sativumLathyrus oleraceust0
- Compound
- sugarse0
- Outcome
- NR synthesise0
- Qualifier
- either as coinducers or as derepressorse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“pisum sativum”
e0“sugars, besides many indirect effects on NR induction, may also directly influence NR synthesis either as coinducers or as derepressors of NR synthesis”
Claim · model-written summary
NR was found not to be a product-inducible enzyme.
- Taxon
- pisum sativumLathyrus oleraceust0
- Outcome
- NR is not a product-inducible enzymee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“pisum sativum”
e0“NR is not a product-inducible enzyme”
The same questions in other papers
sucrose · nutrient: content · Lathyrus oleraceus (pea)Positive and negative results
1 in the opposite direction
- positive
sucrose · physiology: enzyme activity · Lathyrus oleraceus (pea)Positive and negative results
3 papers in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
- positive
1 paper more in this group
See all 5 papers →nitrogen · nutrient: content · Lathyrus oleraceus (pea)Positive and negative results
4 papers in the same direction as this paper · 12 in the opposite direction
- positive
- positive
- positive
13 papers more in this group
See all 17 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.