Abstract
Upon illumination of dark-grown maize seedlings (5 days old) with incandescent light, there occurred a nearly simultaneous increase, after a certain lag period, in the activities of enzymes engaged in the C(4) pathway and the Calvin-Benson cycle. The light-induced biosynthesis of chlorophyll (a and b) precedes the increase in enzyme activities and proceeds without lag phase. A diphasic feature in the elevation of enzyme activities as a function of the intensities of light provided was observed; the increase in enzyme activities was enhanced by light intensities greater than 10(3) ergs per square centimeter per second in comparison with light of lower intensities. Under light intensities greater than 10(3) ergs per square centimeter per second, the simultaneous addition of levulinic acid, which inhibited chlorophyll formation, markedly reduced the increase of enzyme activities. However, neither the diphasic light effect nor the inhibitory effect of levulinic acid was observed with ribulose-1,5-bisphosphate carboxylase. The enzyme activities in the dark-grown maize seedlings were enhanced by a brief irradiation with the red light and the red light effect was reversed by the following far red light treatment. The red light-induced increase in the enzyme activities did not accompany chlorophyll synthesis, and was completely inhibited by cycloheximide, indicating that enzyme synthesis rather than activation might be involved. Light may play a dual role in enzyme induction; one is as an energy source through the photosystems at high intensities and the other is presumably as a signal mediated by phytochrome at low intensities.
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Claims 12
Claim · model-written summary
Illumination increased activities of C4 and Calvin-Benson enzymes after a lag.
- Organ / stage
- seedlingse0
- Treatment
- illuminatione0
- Outcome
- activities of enzymes engaged in the C(4) pathway and the Calvin-Benson cyclee0
- Direction
- increasee0
- Comparator
- dark-growne0
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Upon illumination of dark-grown maize seedlings (5 days old) with incandescent light, there occurred a nearly simultaneous increase, after a certain lag period, in the activities of enzymes engaged in the C(4) pathway and the Calvin-Benson cycle.”
t0“Maize (Zea mays)”
Claim · model-written summary
Light induced chlorophyll biosynthesis before enzyme activity rose and without a lag.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The light-induced biosynthesis of chlorophyll (a and b) precedes the increase in enzyme activities and proceeds without lag phase.”
t0“Maize (Zea mays)”
Claim · model-written summary
Light above 10(3) ergs per square centimeter per second enhanced enzyme activities relative to lower light.
- Treatment
- light intensities greater than 10(3) ergs per square centimeter per seconde0
- Outcome
- enzyme activitiese0
- Direction
- enhancede0
- Comparator
- light of lower intensitiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the increase in enzyme activities was enhanced by light intensities greater than 10(3) ergs per square centimeter per second in comparison with light of lower intensities.”
t0“Maize (Zea mays)”
Claim · model-written summary
Levulinic acid at high light reduced the enzyme activity increase.
- Treatment
- simultaneous addition of levulinic acide0
- Outcome
- increase of enzyme activitiese0
- Direction
- reducede0
- Qualifier
- light intensities greater than 10(3) ergs per square centimeter per seconde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under light intensities greater than 10(3) ergs per square centimeter per second, the simultaneous addition of levulinic acid, which inhibited chlorophyll formation, markedly reduced the increase of enzyme activities.”
t0“Maize (Zea mays)”
Claim · model-written summary
Levulinic acid inhibited chlorophyll formation.
- Treatment
- simultaneous addition of levulinic acide0
- Outcome
- chlorophyll formatione0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the simultaneous addition of levulinic acid, which inhibited chlorophyll formation”
t0“Maize (Zea mays)”
Claim · model-written summary
Ribulose-1,5-bisphosphate carboxylase did not show the diphasic light or levulinic-acid inhibitory effect.
- Gene
- ribulose-1,5-bisphosphate carboxylasee0
- Outcome
- diphasic light effect nor the inhibitory effect of levulinic acide0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“neither the diphasic light effect nor the inhibitory effect of levulinic acid was observed with ribulose-1,5-bisphosphate carboxylase.”
t0“Maize (Zea mays)”
Claim · model-written summary
Brief red-light irradiation enhanced enzyme activities in dark-grown seedlings.
- Treatment
- brief irradiation with the red lighte0
- Outcome
- enzyme activitiese0
- Direction
- enhancede0
- Comparator
- dark-grown maize seedlingse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The enzyme activities in the dark-grown maize seedlings were enhanced by a brief irradiation with the red light”
t0“Maize (Zea mays)”
Claim · model-written summary
Subsequent far-red light reversed the red-light effect on enzyme activity.
- Treatment
- far red light treatmente0
- Outcome
- red light effecte0
- Direction
- reversede0
- Comparator
- red light effecte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the red light effect was reversed by the following far red light treatment.”
t0“Maize (Zea mays)”
Claim · model-written summary
Red-light induced enzyme activity increase occurred without chlorophyll synthesis.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The red light-induced increase in the enzyme activities did not accompany chlorophyll synthesis”
t0“Maize (Zea mays)”
Claim · model-written summary
Cycloheximide completely inhibited the red-light induced enzyme activity increase.
- Treatment
- cycloheximidee0
- Outcome
- red light-induced increase in the enzyme activitiese0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The red light-induced increase in the enzyme activities did not accompany chlorophyll synthesis, and was completely inhibited by cycloheximide”
t0“Maize (Zea mays)”
Claim · model-written summary
The authors infer that enzyme synthesis may mediate the red-light effect.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“indicating that enzyme synthesis rather than activation might be involved.”
t0“Maize (Zea mays)”
Claim · model-written summary
The authors propose high-intensity energy supply and low-intensity phytochrome signalling as two roles of light in enzyme induction.
- Outcome
- enzyme inductione0
- Qualifier
- as an energy source through the photosystems at high intensities and the other is presumably as a signal mediated by phytochrome at low intensitiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Light may play a dual role in enzyme induction; one is as an energy source through the photosystems at high intensities and the other is presumably as a signal mediated by phytochrome at low intensities.”
t0“Maize (Zea mays)”
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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.