Abstract
When the epicotyls of etiolated 7 d pea seedlings were illuminated, there was a rapid rise in the lignin content of the apical shoot (consisting of the third internode with its terminal bud), to give a 10-fold increase after 24 h; there was no change in the unilluminated controls. About 80% of the lignin in the apical shoot was found in the stem internode, both before and after illumination. Over this period, the activities of phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, and 4-coumarate: CoA ligase increased co-ordinately up to five times those of the dark controls over 12 h, when lignification was most rapid, and then declined to about half their maximum activity. All three enzymes showed the same 1.5 h lag period before increasing. By comparison, no increases were observed in the later enzymes of lignin biosynthesis, namely S-adenosylmethionine: caffeate O-methyltransferase, cinnamoyl-CoA reductase, NADP+-cinnamyl alcohol dehydrogenase, and cell-wall peroxidase, but the proportions of these enzymes in buds and stem internodes were close to the distribution of lignin between them, both before and after illumination. Two forms of 4-coumarate: CoA ligase were found; despite their different activities and substrate specificities, both forms showed substantial changes. The results suggest that lignogenesis is initiated by an increase in the activities of the three enzymes of general phenylpropanoid metabolism in cells already containing enzymes catalysing the later stages of lignin synthesis; they are discussed in relation to biochemical and anatomical differentiation within plant organs generally.
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Claims 9
Claim · model-written summary
Illumination increased apical-shoot lignin tenfold after 24 h.
- Taxon
- pea
Lathyrus oleraceuse0 - Organ / stage
- apical shoote0
- Treatment
- illuminatede0
- Outcome
- lignin contente0
- Direction
- increasee0
- Value
- 10-folde0
- Comparator
- unilluminated controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When the epicotyls of etiolated 7 d pea seedlings were illuminated, there was a rapid rise in the lignin content of the apical shoot (consisting of the third internode with its terminal bud), to give a 10-fold increase after 24 h; there was no change in the unilluminated controls.”
Claim · model-written summary
About 80% of apical-shoot lignin was in the stem internode before and after illumination.
- Taxon
- peaLathyrus oleraceust0
- Organ / stage
- stem internodee0
- Outcome
- lignin in the apical shoote0
- Value
- 80%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“About 80% of the lignin in the apical shoot was found in the stem internode, both before and after illumination.”
t0“Pea”
Claim · model-written summary
Phenylalanine ammonia-lyase activity rose up to fivefold during illumination.
- Taxon
- peaLathyrus oleraceust0
- Treatment
- illuminatione1
- Gene
- phenylalanine ammonia-lyasee0
- Outcome
- activitiese0
- Direction
- increasede0
- Value
- five timese0
- Comparator
- dark controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the activities of phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, and 4-coumarate: CoA ligase increased co-ordinately up to five times those of the dark controls over 12 h”
t0“Pea”
e1“the distribution of lignin between them, both before and after illumination.”
Claim · model-written summary
Cinnamate 4-hydroxylase activity rose up to fivefold during illumination.
- Taxon
- peaLathyrus oleraceust0
- Treatment
- illuminatione1
- Gene
- cinnamate 4-hydroxylasee0
- Outcome
- activitiese0
- Direction
- increasede0
- Value
- five timese0
- Comparator
- dark controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the activities of phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, and 4-coumarate: CoA ligase increased co-ordinately up to five times those of the dark controls over 12 h”
t0“Pea”
e1“the distribution of lignin between them, both before and after illumination.”
Claim · model-written summary
4-coumarate: CoA ligase activity rose up to fivefold during illumination.
- Taxon
- peaLathyrus oleraceust0
- Treatment
- illuminatione1
- Gene
- 4-coumarate: CoA ligasee0
- Outcome
- activitiese0
- Direction
- increasede0
- Value
- five timese0
- Comparator
- dark controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the activities of phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, and 4-coumarate: CoA ligase increased co-ordinately up to five times those of the dark controls over 12 h”
t0“Pea”
e1“the distribution of lignin between them, both before and after illumination.”
Claim · model-written summary
The three early enzymes had a 1.5 h lag and later fell to half maximum activity.
- Taxon
- peaLathyrus oleraceust0
- Outcome
- lag periode0
- Value
- 1.5 he0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All three enzymes showed the same 1.5 h lag period before increasing.”
t0“Pea”
Claim · model-written summary
Later lignin-biosynthesis enzymes did not increase during illumination.
- Taxon
- peaLathyrus oleraceust0
- Treatment
- illuminatione1
- Outcome
- later enzymes of lignin biosynthesise0
- Direction
- no increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no increases were observed in the later enzymes of lignin biosynthesis, namely S-adenosylmethionine: caffeate O-methyltransferase, cinnamoyl-CoA reductase, NADP+-cinnamyl alcohol dehydrogenase, and cell-wall peroxidase”
t0“Pea”
e1“the distribution of lignin between them, both before and after illumination.”
Claim · model-written summary
Two 4-coumarate: CoA ligase forms were found and both changed substantially.
- Taxon
- peaLathyrus oleraceust0
- Gene
- 4-coumarate: CoA ligasee0
- Outcome
- Two formse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Two forms of 4-coumarate: CoA ligase were found; despite their different activities and substrate specificities, both forms showed substantial changes.”
t0“Pea”
Claim · model-written summary
The authors infer early phenylpropanoid enzyme activation initiates lignogenesis.
- Taxon
- peaLathyrus oleraceust0
- Outcome
- lignogenesise0
- Qualifier
- increase in the activities of the three enzymes of general phenylpropanoid metabolisme0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lignogenesis is initiated by an increase in the activities of the three enzymes of general phenylpropanoid metabolism”
t0“Pea”
The same questions in other papers
light · physiology: enzyme activity · Lathyrus oleraceus (pea)Positive and negative results
7 in the opposite direction
- positive
- positive
- positive
4 papers more in this group
See all 8 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.