Abstract
The cereal aleurone layer is a secretory tissue whose function is regulated by gibberellic acid (GA) and abscisic acid (ABA). Aleurone cells lack functional chloroplasts, thus excluding photosynthesis as a source of active oxygen species (AOS) in cell death. Incubation of barley aleurone layers or protoplasts in GA initiated the cell death programme, but incubation in ABA delays programmed cell death (PCD). Light, especially blue and UV-A light, and H(2)O(2) accelerate PCD of GA-treated aleurone cells, but ABA-treated aleurone cells are refractory to light and H(2)O(2) and are not killed. It was shown that light elevated intracellular H(2)O(2), and that the rise in H(2)O(2) was greater in GA-treated cells compared to cells in ABA. Experiments with antioxidants show that PCD in aleurone is probably regulated by AOS. The sensitivity of GA-treated aleurone to light and H(2)O(2) is a result of lowered amounts of enzymes that metabolize AOS. mRNAs encoding catalase, ascorbate peroxidase and superoxide dismutase are all reduced during 6-18 h of incubation in GA, but these mRNAs were present in higher amounts in cells incubated in ABA. The amounts of protein and enzyme activities encoded by these mRNAs were also dramatically reduced in GA-treated cells. Aleurone cells store and metabolize neutral lipids via the glyoxylate cycle in response to GA, and glyoxysomes are one potential source of AOS in the GA-treated cells. Mitochondria are another potential source of AOS in GA-treated cells. AOS generated by these organelles bring about membrane rupture and cell death.
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Claims 13
Claim · model-written summary
Barley aleurone cells lack functional chloroplasts.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaret0 - Organ / stage
- Aleurone cellse0
- Outcome
- lack functional chloroplastse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Aleurone cells lack functional chloroplasts”
t0“barley”
Claim · model-written summary
GA initiated cell death programme in barley aleurone.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- GAe0
- Outcome
- cell death programmee0
- Direction
- initiatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Incubation of barley aleurone layers or protoplasts in GA initiated the cell death programme, but incubation in ABA delays programmed cell death (PCD).”
Claim · model-written summary
ABA delays programmed cell death (PCD) in barley aleurone.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- ABAe0
- Outcome
- programmed cell death (PCD)e0
- Direction
- delayse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Incubation of barley aleurone layers or protoplasts in GA initiated the cell death programme, but incubation in ABA delays programmed cell death (PCD).”
Claim · model-written summary
Light, particularly blue and UV-A, and hydrogen peroxide accelerated death in GA-treated aleurone cells.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- Light, especially blue and UV-A light, and H(2)O(2)e0
- Outcome
- PCDe0
- Direction
- acceleratee0
- Qualifier
- GA-treated aleurone cellse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Light, especially blue and UV-A light, and H(2)O(2) accelerate PCD of GA-treated aleurone cells”
t0“barley”
Claim · model-written summary
ABA-treated aleurone cells resisted light and hydrogen peroxide and survived.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- light and H(2)O(2)e0
- Outcome
- not killede0
- Qualifier
- ABA-treated aleurone cellse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ABA-treated aleurone cells are refractory to light and H(2)O(2) and are not killed.”
t0“barley”
Claim · model-written summary
Light raised intracellular hydrogen peroxide, with a larger rise under GA than ABA.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- lighte0
- Outcome
- intracellular H(2)O(2)e0
- Direction
- elevatede0
- Qualifier
- GA-treated cellse0
- Comparator
- cells in ABAe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“light elevated intracellular H(2)O(2), and that the rise in H(2)O(2) was greater in GA-treated cells compared to cells in ABA.”
t0“barley”
Claim · model-written summary
Antioxidant experiments suggested active oxygen species regulate aleurone cell death.
- Taxon
- barleyHordeum vulgaret0
- Outcome
- PCD in aleuronee0
- Qualifier
- regulated by AOSe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Experiments with antioxidants show that PCD in aleurone is probably regulated by AOS.”
t0“barley”
Claim · model-written summary
Reduced amounts of active oxygen metabolizing enzymes explained GA-treated aleurone sensitivity to light and peroxide.
- Taxon
- barleyHordeum vulgaret0
- Outcome
- sensitivity of GA-treated aleurone to light and H(2)O(2)e0
- Qualifier
- lowered amounts of enzymes that metabolize AOSe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The sensitivity of GA-treated aleurone to light and H(2)O(2) is a result of lowered amounts of enzymes that metabolize AOS.”
t0“barley”
Claim · model-written summary
Catalase, ascorbate peroxidase and superoxide dismutase transcripts fell during 6–18 hours of GA incubation and were higher under ABA.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- GAe0
- Gene
- catalase, ascorbate peroxidase and superoxide dismutasee0
- Outcome
- mRNAs encoding catalase, ascorbate peroxidase and superoxide dismutasee0
- Direction
- reducede0
- Qualifier
- during 6-18 he0
- Comparator
- ABAe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mRNAs encoding catalase, ascorbate peroxidase and superoxide dismutase are all reduced during 6-18 h of incubation in GA, but these mRNAs were present in higher amounts in cells incubated in ABA.”
t0“barley”
Claim · model-written summary
GA dramatically reduced the corresponding proteins and enzyme activities.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- GAe0
- Outcome
- amounts of protein and enzyme activitiese0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The amounts of protein and enzyme activities encoded by these mRNAs were also dramatically reduced in GA-treated cells.”
t0“barley”
Claim · model-written summary
GA-responsive aleurone cells stored and metabolized neutral lipids via the glyoxylate cycle.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- GAe0
- Outcome
- store and metabolize neutral lipids via the glyoxylate cyclee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Aleurone cells store and metabolize neutral lipids via the glyoxylate cycle in response to GA”
t0“barley”
Claim · model-written summary
Glyoxysomes and mitochondria were proposed as sources of active oxygen species in GA-treated cells.
- Taxon
- barleyHordeum vulgaret0
- Outcome
- source of AOSe0
- Qualifier
- GA-treated cellse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“glyoxysomes are one potential source of AOS in the GA-treated cells. Mitochondria are another potential source of AOS in GA-treated cells.”
t0“barley”
Claim · model-written summary
Organelle-generated active oxygen species were asserted to cause membrane rupture and cell death.
- Taxon
- barleyHordeum vulgaret0
- Outcome
- membrane rupture and cell deathe0
- Qualifier
- AOS generated by these organellese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“AOS generated by these organelles bring about membrane rupture and cell death.”
t0“barley”
The same questions in other papers
Gibberellic acid · cytology · Hordeum vulgare (barley)Positive and negative results
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- positive
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See all 5 papers →(+)-abscisic acid · cytology · Hordeum vulgare (barley)Results agree
1 paper in the same direction as this paper
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hydrogen peroxide · cytology · Hordeum vulgare (barley)Results agree
2 papers in the same direction as this paper
- negative
- negative
light · cytology · Hordeum vulgare (barley)Results agree
1 paper in the same direction as this paper
- negative
uv · cytology · 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.