Abstract
The exposure of detached leaves of C3 plants (pea, barley) and C4 plant (maize) to 5 mM Pb (NO3)2 for 24 h caused a reduction of their photosynthetic activity by 40-60%, whereas the respiratory rate was stimulated by 20-50%. Mitochondria isolated from Pb2+-treated pea leaves oxidized substrates (glycine, succinate, malate) at higher rates than mitochondria from control leaves. The respiratory control (RCR) and the ADP/O ratio were not affected. Pb2+ caused an increase in ATP content and the ATP/ADP ratio in pea and maize leaves. Rapid fractionation of barley protoplasts incubated at low and high CO2 conditions, indicated that the increased ATP/ADP ratio in Pb2+-treated leaves resulted mainly from the production of mitochondrial ATP. The measurements of membrane potential of mitochondria with a TPP+-sensitive electrode further showed that mitochondria isolated from Pb2+-treated leaves had at least as high membrane potential as mitochondria from control leaves. The activity of NAD-malate dehydrogenase in the protoplasts from barley leaves treated with Pb2+ was 3-fold higher than in protoplasts from control leaves. The activities of photorespiratory enzymes NADH-hydroxypyruvate reductase and glycolate oxidase as well as of NAD-malic enzyme were not affected. The presented data indicate that stimulation of respiration in leaves treated by lead is in a close relationship with activation of malate dehydrogenase and stimulation of the mitochondrial ATP production. Thus, respiration might fulfil a protective role during heavy metal exposure.
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 11
Claim · model-written summary
Lead exposure reduced photosynthetic activity in pea, barley and maize leaves by 40-60%.
- Taxon
- pea, barley
Lathyrus oleraceus.jpg?width=60)
Hordeum vulgaree0 - Treatment
- 5 mM Pb (NO3)2 for 24 he0
- Outcome
- photosynthetic activitye0
- Direction
- reductione0
- Value
- 40-60%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“detached leaves of C3 plants (pea, barley) and C4 plant (maize) to 5 mM Pb (NO3)2 for 24 h caused a reduction of their photosynthetic activity by 40-60%”
Claim · model-written summary
Lead exposure stimulated leaf respiratory rate by 20-50%.
Zea maysNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“detached leaves of C3 plants (pea, barley) and C4 plant (maize) to 5 mM Pb (NO3)2 for 24 h caused a reduction of their photosynthetic activity by 40-60%, whereas the respiratory rate was stimulated by 20-50%”
Claim · model-written summary
Mitochondria from lead treated pea leaves oxidized glycine, succinate and malate faster than controls.
- Taxon
- peaLathyrus oleraceuse0
- Treatment
- Pb2+-treatede0
- Outcome
- oxidized substrates (glycine, succinate, malate)e0
- Direction
- higher ratese0
- Comparator
- control leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Mitochondria isolated from Pb2+-treated pea leaves oxidized substrates (glycine, succinate, malate) at higher rates than mitochondria from control leaves”
Claim · model-written summary
Respiratory control and ADP/O ratio were unaffected by lead treatment.
- Taxon
- peaLathyrus oleraceuse0
- Treatment
- Pb2+-treatede0
- Outcome
- respiratory control (RCR) and the ADP/O ratioe1
- Direction
- not affectede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pb2+-treated pea leaves”
e1“The respiratory control (RCR) and the ADP/O ratio were not affected”
Claim · model-written summary
Lead increased ATP content and ATP/ADP ratio in pea and maize leaves.
- Taxon
- peaLathyrus oleraceuse0
- Treatment
- Pb2+e0
- Outcome
- ATP content and the ATP/ADP ratioe0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pb2+ caused an increase in ATP content and the ATP/ADP ratio in pea and maize leaves”
Claim · model-written summary
The increased ATP/ADP ratio in lead treated barley leaves arose mainly from mitochondrial ATP production.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- Pb2+-treatede0
- Outcome
- increased ATP/ADP ratioe0
- Qualifier
- production of mitochondrial ATPe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“barley protoplasts incubated at low and high CO2 conditions, indicated that the increased ATP/ADP ratio in Pb2+-treated leaves resulted mainly from the production of mitochondrial ATP”
Claim · model-written summary
Mitochondria from lead treated leaves had at least as high membrane potential as controls.
- Taxon
- peaLathyrus oleraceuse0
- Treatment
- Pb2+-treatede1
- Outcome
- membrane potentiale1
- Direction
- at least as highe1
- Comparator
- control leavese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“pea leaves”
e1“mitochondria isolated from Pb2+-treated leaves had at least as high membrane potential as mitochondria from control leaves”
Claim · model-written summary
Lead raised NAD-malate dehydrogenase activity threefold in barley protoplasts.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- Pb2+e0
- Gene
- NAD-malate dehydrogenasee0
- Outcome
- activity of NAD-malate dehydrogenasee0
- Direction
- highere0
- Value
- 3-folde0
- Comparator
- control leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“activity of NAD-malate dehydrogenase in the protoplasts from barley leaves treated with Pb2+ was 3-fold higher than in protoplasts from control leaves”
Claim · model-written summary
Lead did not affect NADH-hydroxypyruvate reductase, glycolate oxidase or NAD-malic enzyme activity.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- Pb2+e0
- Outcome
- activities of photorespiratory enzymes NADH-hydroxypyruvate reductase and glycolate oxidase as well as of NAD-malic enzymee1
- Direction
- not affectede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“barley leaves treated with Pb2+”
e1“The activities of photorespiratory enzymes NADH-hydroxypyruvate reductase and glycolate oxidase as well as of NAD-malic enzyme were not affected”
Claim · model-written summary
The authors link lead stimulated respiration to malate dehydrogenase activation and mitochondrial ATP production.
- Taxon
- barleyHordeum vulgaree1
- Treatment
- leade0
- Outcome
- stimulation of respiratione0
- Qualifier
- activation of malate dehydrogenase and stimulation of the mitochondrial ATP productione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“stimulation of respiration in leaves treated by lead is in a close relationship with activation of malate dehydrogenase and stimulation of the mitochondrial ATP production”
e1“barley leaves treated with Pb2+”
Claim · model-written summary
The authors suggest respiration may protect leaves during heavy metal exposure.
- Taxon
- peaLathyrus oleraceuse0
- Outcome
- protective rolee1
- Qualifier
- respiratione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“pea leaves”
e1“respiration might fulfil a protective role during heavy metal exposure”
The same questions in other papers
lead atom · physiology: photosynthesis · Lathyrus oleraceus (pea)Results agree
1 paper in the same direction as this paper
- negative
lead atom · physiology: photosynthesis · Hordeum vulgare (barley)Results agree
4 papers in the same direction as this paper
- negative
- negative
- negative
1 paper more in this group
See all 5 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.