Abstract
Maize (Zea mays L.) plants were grown to the nine-leaf stage. Despite a saturating N supply, the youngest mature leaves (seventh position on the stem) contained little NO3- reserve. Droughted plants (deprived of nutrient solution) showed changes in foliar enzyme activities, mRNA accumulation, photosynthesis, and carbohydrate and amino acid contents. Total leaf water potential and CO2 assimilation rates, measured 3 h into the photoperiod, decreased 3 d after the onset of drought. Starch, glucose, fructose, and amino acids, but not sucrose (Suc), accumulated in the leaves of droughted plants. Maximal extractable phosphoenolpyruvate carboxylase activities increased slightly during water deficit, whereas the sensitivity of this enzyme to the inhibitor malate decreased. Maximal extractable Suc phosphate synthase activities decreased as a result of water stress, and there was an increase in the sensitivity to the inhibitor orthophosphate. A correlation between maximal extractable foliar nitrate reductase (NR) activity and the rate of CO2 assimilation was observed. The NR activation state and maximal extractable NR activity declined rapidly in response to drought. Photosynthesis and NR activity recovered rapidly when nutrient solution was restored at this point. The decrease in maximal extractable NR activity was accompanied by a decrease in NR transcripts, whereas Suc phosphate synthase and phosphoenolpyruvate carboxylase mRNAs were much less affected. The coordination of N and C metabolism is retained during drought conditions via modulation of the activities of Suc phosphate synthase and NR commensurate with the prevailing rate of photosynthesis.
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Claims 16
Claim · model-written summary
Young mature maize leaves had little nitrate reserve despite saturating N.
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Despite a saturating N supply, the youngest mature leaves (seventh position on the stem) contained little NO3- reserve”
t0“Maize”
Claim · model-written summary
Drought reduced leaf water potential after three days.
- Treatment
- droughte0
- Outcome
- Total leaf water potentiale0
- Direction
- decreasede0
- Qualifier
- 3 d after the onset of droughte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total leaf water potential and CO2 assimilation rates, measured 3 h into the photoperiod, decreased 3 d after the onset of drought”
t0“Maize”
Claim · model-written summary
Drought reduced CO2 assimilation after three days.
- Treatment
- droughte0
- Outcome
- CO2 assimilation ratese0
- Direction
- decreasede0
- Qualifier
- 3 d after the onset of droughte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total leaf water potential and CO2 assimilation rates, measured 3 h into the photoperiod, decreased 3 d after the onset of drought”
t0“Maize”
Claim · model-written summary
Starch, glucose, and fructose accumulated in droughted leaves.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starch, glucose, fructose, and amino acids, but not sucrose (Suc), accumulated in the leaves of droughted plants”
t0“Maize”
Claim · model-written summary
Amino acids accumulated in droughted leaves.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starch, glucose, fructose, and amino acids, but not sucrose (Suc), accumulated in the leaves of droughted plants”
t0“Maize”
Claim · model-written summary
Sucrose did not accumulate in droughted leaves.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starch, glucose, fructose, and amino acids, but not sucrose (Suc), accumulated in the leaves of droughted plants”
t0“Maize”
Claim · model-written summary
Water deficit slightly increased extractable PEP carboxylase activity.
- Treatment
- water deficite0
- Gene
- phosphoenolpyruvate carboxylasee0
- Outcome
- Maximal extractable phosphoenolpyruvate carboxylase activitiese0
- Direction
- increased slightlye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maximal extractable phosphoenolpyruvate carboxylase activities increased slightly during water deficit”
t0“Maize”
Claim · model-written summary
Water deficit decreased PEP carboxylase sensitivity to malate.
- Treatment
- water deficite1
- Compound
- malatee0
- Outcome
- sensitivity of this enzyme to the inhibitor malatee0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the sensitivity of this enzyme to the inhibitor malate decreased”
t0“Maize”
e1“during water deficit”
Claim · model-written summary
Water stress decreased sucrose phosphate synthase activity.
- Treatment
- water stresse0
- Gene
- Suc phosphate synthasee0
- Outcome
- Maximal extractable Suc phosphate synthase activitiese0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maximal extractable Suc phosphate synthase activities decreased as a result of water stress”
t0“Maize”
Claim · model-written summary
Water stress increased sucrose phosphate synthase sensitivity to orthophosphate.
- Treatment
- water stresse1
- Compound
- orthophosphatee0
- Outcome
- sensitivity to the inhibitor orthophosphatee0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there was an increase in the sensitivity to the inhibitor orthophosphate”
t0“Maize”
e1“as a result of water stress”
Claim · model-written summary
Maximum nitrate reductase activity correlated with CO2 assimilation.
- Gene
- nitrate reductase (NR)e0
- Outcome
- maximal extractable foliar nitrate reductase (NR) activitye0
- Qualifier
- rate of CO2 assimilatione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A correlation between maximal extractable foliar nitrate reductase (NR) activity and the rate of CO2 assimilation was observed”
t0“Maize”
Claim · model-written summary
Drought rapidly reduced nitrate reductase activation state and activity.
- Treatment
- droughte0
- Outcome
- NR activation state and maximal extractable NR activitye0
- Direction
- declined rapidlye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The NR activation state and maximal extractable NR activity declined rapidly in response to drought”
t0“Maize”
Claim · model-written summary
Photosynthesis and nitrate reductase activity recovered upon nutrient restoration.
- Treatment
- nutrient solution was restorede0
- Outcome
- Photosynthesis and NR activitye0
- Direction
- recovered rapidlye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Photosynthesis and NR activity recovered rapidly when nutrient solution was restored at this point”
t0“Maize”
Claim · model-written summary
Nitrate reductase transcripts declined with extractable activity.
- Gene
- NRe0
- Outcome
- NR transcriptse0
- Direction
- decreasee0
- Qualifier
- decrease in maximal extractable NR activitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The decrease in maximal extractable NR activity was accompanied by a decrease in NR transcripts”
t0“Maize”
Claim · model-written summary
Sucrose phosphate synthase and PEP carboxylase mRNAs were much less affected.
- Gene
- Suc phosphate synthase and phosphoenolpyruvate carboxylasee0
- Outcome
- mRNAs were much less affectede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Suc phosphate synthase and phosphoenolpyruvate carboxylase mRNAs were much less affected”
t0“Maize”
Claim · model-written summary
The authors infer coordinated N and C metabolism during drought through synthase and NR activities.
- Gene
- Suc phosphate synthase and NRe0
- Outcome
- coordination of N and C metabolism is retainede0
- Qualifier
- drought conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The coordination of N and C metabolism is retained during drought conditions via modulation of the activities of Suc phosphate synthase and NR commensurate with the prevailing rate of photosynthesis”
t0“Maize”
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See all 155 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.