Abstract
The chlorophyll (Chl) biosynthetic reactions were monitored during senescence of dark-incubated excised barley (Hordeum vulgare L. cv IB 65) leaves floated in double-distilled water or kinetin solution. Kinetin abolished the degradation of Chl but failed to check the net degradation of protochlorophyllide (Pchlide), suggesting that different sets of enzymes, i.e. kinetin sensitive and insensitive, are responsible for the degradation of Chl and Pchlide, respectively. Upon exposure of the leaves to light, the dark-accumulated Pchlide was efficiently phototransformed to chorophyllide (Chlide), even on the 7th d of dark incubation, demonstrating that the activity of Pchlide reductase, one of the late enzymes of the Chl biosynthetic pathway, is not substantially affected during senescence. The senescing leaves continued to synthesize Pchlide and Chlide until the 7th d, although at a reduced rate (20% of the 1st d). The decline of the rate of synthesis of Pchlide and Chlide is due to the loss of activity of two early enzymes of the Chl biosynthetic pathway, i.e. 5-aminolevulinic acid dehydratase and porphobilinogen deaminase. Kinetin substantially checked the loss of activity of these two enzymes.
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Claims 6
Claim · model-written summary
Kinetin prevented chlorophyll degradation in dark incubated barley leaves.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaree1 - Organ / stage
- leavese1
- Treatment
- Kinetine0
- Outcome
- degradation of Chle0
- Direction
- abolishede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Kinetin abolished the degradation of Chl but failed to check the net degradation of protochlorophyllide (Pchlide)”
e1“barley (Hordeum vulgare L. cv IB 65) leaves”
Claim · model-written summary
Kinetin failed to prevent net protochlorophyllide degradation.
- Taxon
- barleyHordeum vulgaree1
- Treatment
- Kinetine0
- Outcome
- net degradation of protochlorophyllide (Pchlide)e0
- Direction
- failed to checke0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Kinetin abolished the degradation of Chl but failed to check the net degradation of protochlorophyllide (Pchlide)”
e1“barley (Hordeum vulgare L. cv IB 65) leaves”
Claim · model-written summary
Light phototransformed accumulated protochlorophyllide to chlorophyllide even on day seven of dark incubation.
- Taxon
- barleyHordeum vulgaree1
- Treatment
- lighte0
- Outcome
- dark-accumulated Pchlide was efficiently phototransformed to chorophyllide (Chlide)e0
- Qualifier
- 7th d of dark incubatione0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Upon exposure of the leaves to light, the dark-accumulated Pchlide was efficiently phototransformed to chorophyllide (Chlide), even on the 7th d of dark incubation”
e1“barley (Hordeum vulgare L. cv IB 65) leaves”
Claim · model-written summary
Senescing leaves still synthesized protochlorophyllide and chlorophyllide on day seven, at 20% of the first day rate.
- Taxon
- barleyHordeum vulgaree1
- Organ / stage
- leavese0
- Outcome
- synthesize Pchlide and Chlidee0
- Direction
- reducede0
- Value
- 20% of the 1st de0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The senescing leaves continued to synthesize Pchlide and Chlide until the 7th d, although at a reduced rate (20% of the 1st d).”
e1“barley (Hordeum vulgare L. cv IB 65) leaves”
Claim · model-written summary
The authors attribute the reduced synthesis of protochlorophyllide and chlorophyllide to loss of two early enzyme activities.
- Taxon
- barleyHordeum vulgaree1
- Gene
- 5-aminolevulinic acid dehydratase and porphobilinogen deaminasee0
- Outcome
- decline of the rate of synthesis of Pchlide and Chlidee0
- Direction
- declinee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The decline of the rate of synthesis of Pchlide and Chlide is due to the loss of activity of two early enzymes of the Chl biosynthetic pathway, i.e. 5-aminolevulinic acid dehydratase and porphobilinogen deaminase.”
e1“barley (Hordeum vulgare L. cv IB 65) leaves”
Claim · model-written summary
Kinetin substantially prevented the loss of activity of the two early chlorophyll biosynthetic enzymes.
- Taxon
- barleyHordeum vulgaree2
- Treatment
- Kinetine0
- Gene
- 5-aminolevulinic acid dehydratase and porphobilinogen deaminasee1
- Outcome
- loss of activity of these two enzymese0
- Direction
- checkede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Kinetin substantially checked the loss of activity of these two enzymes.”
e1“5-aminolevulinic acid dehydratase and porphobilinogen deaminase.”
e2“barley (Hordeum vulgare L. cv IB 65) leaves”
The same questions in other papers
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1 paper in the same direction as this paper · 4 in the opposite direction
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2 papers more in this group
See all 6 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.