Abstract
The effect of treatment of etiolated maize seedlings with UV-B and UV-A radiation, and different levels of photosynthetically active radiation (PAR, 400–700 nm), on the activity and quantity of NADP-malic enzyme (NADP-ME) and on RNA levels was determined. Under low levels of PAR (14 μmol m–2 s–1), exposure to UV-B radiation (9 μmol m–2 s–1) but not UV-A radiation (11 μmol m–2 s–1) for 6–24 h caused a marked increase in the activity of the enzyme similar to that observed under high PAR (300 μmol m–2 s–1) in the absence of UV-B. Western blot analysis indicated there was a specific increase of the photosynthetically active isoform of the enzyme. This increase was also measured at the RNA level by dot blot analysis, indicating that the induction is displayed at the level of NADP-ME transcription. UV-B treatment of green leaves after a 12 h dark period also caused an increase in the activity and level of NADP-ME. The UV-B induction of NADP-ME synthesis may reflect a mechanism for induction of photosynthetic processes in C4 photosynthesis. Alternatively, the relatively low intensity of UV-B radiation present under full sunlight might provide a signal that facilitates repair of UV-B-induced damage through the increased activity of different enzymes such as NADP-ME. It is speculated that the reducing power and pyruvate generated by activity of NADP-ME may be used for respiration in cellular repair processes and as substrates for the fatty acid synthesis required for membrane repair.
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 6
Claim · model-written summary
Under low PAR, UV-B increased NADP-malic enzyme activity in etiolated maize seedlings.
- Organ / stage
- seedlingst0
- Treatment
- UV-B radiation (9 μmol m–2 s–1)e0
- Gene
- NADP-malic enzymet0
- Outcome
- activity of the enzymee0
- Direction
- increasee0
- Qualifier
- 6–24 he0
- Comparator
- low levels of PAR (14 μmol m–2 s–1)e0
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under low levels of PAR (14 μmol m–2 s–1), exposure to UV-B radiation (9 μmol m–2 s–1) but not UV-A radiation (11 μmol m–2 s–1) for 6–24 h caused a marked increase in the activity of the enzyme similar to that observed under high PAR (300 μmol m–2 s–1) in the absence of UV-B”
t0“UV-B induction of NADP-malic enzyme in etiolated and green maize seedlings”
Claim · model-written summary
UV-A radiation did not increase enzyme activity under low PAR.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“exposure to UV-B radiation (9 μmol m–2 s–1) but not UV-A radiation (11 μmol m–2 s–1) for 6–24 h caused a marked increase in the activity of the enzyme”
t0“UV-B induction of NADP-malic enzyme in etiolated and green maize seedlings”
Claim · model-written summary
High PAR without UV-B produced enzyme activity similar to UV-B exposure under low PAR.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“similar to that observed under high PAR (300 μmol m–2 s–1) in the absence of UV-B”
t0“UV-B induction of NADP-malic enzyme in etiolated and green maize seedlings”
Claim · model-written summary
UV-B increased the photosynthetically active enzyme isoform.
- Treatment
- UV-Bt0
- Gene
- NADP-malic enzymet0
- Outcome
- photosynthetically active isoform of the enzymee0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Western blot analysis indicated there was a specific increase of the photosynthetically active isoform of the enzyme”
t0“UV-B induction of NADP-malic enzyme in etiolated and green maize seedlings”
Claim · model-written summary
UV-B increased NADP-ME RNA, consistent with transcriptional induction.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This increase was also measured at the RNA level by dot blot analysis, indicating that the induction is displayed at the level of NADP-ME transcription”
t0“UV-B induction of NADP-malic enzyme in etiolated and green maize seedlings”
Claim · model-written summary
UV-B increased NADP-ME activity in green leaves after 12 hours of darkness.
- Organ / stage
- green leavese0
- Treatment
- UV-B treatmente0
- Gene
- NADP-MEe0
- Outcome
- activity and level of NADP-MEe0
- Direction
- increasee0
- Qualifier
- after a 12 h dark periode0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“UV-B treatment of green leaves after a 12 h dark period also caused an increase in the activity and level of NADP-ME”
t0“UV-B induction of NADP-malic enzyme in etiolated and green maize seedlings”
The same questions in other papers
uv · physiology: photosynthesis · Zea mays (maize)Results differ
3 papers in the same direction as this paper · 6 in the opposite direction
- no effect
- negative
- negative
6 papers more in this group
See all 10 papers →light · physiology: enzyme activity · Zea mays (maize)Positive and negative results
11 papers in the same direction as this paper · 7 in the opposite direction
- positive
- positive
- no effect
15 papers more in this group
See all 19 papers →uv · physiology: enzyme activity · Zea mays (maize)Results agree
2 papers in the same direction as this paper
- positive
- positive
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.