Abstract
The role of the ascorbate‐glutathione cycle and AOS detoxification was investigated during leaf growth of defoliated and undefoliated plants of ryegrass ( Lolium perenne L. cv. Bravo). Antioxidants and related enzymatic activities were located in elongating leaf bases (ELBs) of undefoliated plants, following a decreasing gradient from basal (meristem) to distal segments, inverse to H 2 O 2 levels. In the meristematic zone, the intense activity of the ascorbate‐glutathione cycle and the supply of reducing power by the oxidative pentose phosphate pathway allowed the maintenance of both antioxidant reduction and H 2 O 2 detoxification. BCNU (1–3 bis(2‐chloroethyl)‐ N ‐nitrosourea), a glutathione reductase inhibitor, induced an increase in the meristematic zone in both H 2 O 2 and antioxidant levels and a decrease in reduced/oxidized ratios of glutathione and ascorbate. These changes were associated with a reduced foliar regrowth activity. In the absence of BCNU, defoliation did not modify the ratios of reduced/oxidized antioxidants, although it triggered a temporary increase in H 2 O 2 level. The results are discussed on the basis of a possible control of leaf growth by glutathione and ascorbate.
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Claims 7
Claim · model-written summary
Antioxidants and related enzymes declined from basal to distal elongating leaf-base segments, opposite the hydrogen peroxide gradient.
- Organ / stage
- elongating leaf bases (ELBs)e0
- Outcome
- Antioxidants and related enzymatic activitiese0
- Direction
- decreasing gradiente0
LoliumOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Antioxidants and related enzymatic activities were located in elongating leaf bases (ELBs) of undefoliated plants, following a decreasing gradient from basal (meristem) to distal segments, inverse to H 2 O 2 levels.”
t0“ryegrass”
Claim · model-written summary
In the meristem, ascorbate-glutathione cycling and pentose phosphate reducing power maintained antioxidant reduction and hydrogen peroxide detoxification.
- Outcome
- antioxidant reduction and H 2 O 2 detoxificatione0
- Qualifier
- supply of reducing power by the oxidative pentose phosphate pathwaye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the meristematic zone, the intense activity of the ascorbate‐glutathione cycle and the supply of reducing power by the oxidative pentose phosphate pathway allowed the maintenance of both antioxidant reduction and H 2 O 2 detoxification.”
t0“ryegrass”
Claim · model-written summary
BCNU increased meristematic hydrogen peroxide and antioxidant levels.
- Organ / stage
- meristematic zonee0
- Treatment
- BCNUe0
- Outcome
- H 2 O 2 and antioxidant levelse0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“BCNU (1–3 bis(2‐chloroethyl)‐ N ‐nitrosourea), a glutathione reductase inhibitor, induced an increase in the meristematic zone in both H 2 O 2 and antioxidant levels and a decrease in reduced/oxidized ratios of glutathione and ascorbate.”
t0“ryegrass”
Claim · model-written summary
BCNU decreased reduced-to-oxidized glutathione and ascorbate ratios.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“BCNU (1–3 bis(2‐chloroethyl)‐ N ‐nitrosourea), a glutathione reductase inhibitor, induced an increase in the meristematic zone in both H 2 O 2 and antioxidant levels and a decrease in reduced/oxidized ratios of glutathione and ascorbate.”
t0“ryegrass”
Claim · model-written summary
Those BCNU-associated changes accompanied reduced foliar regrowth.
Not reportedTreatment
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These changes were associated with a reduced foliar regrowth activity.”
t0“ryegrass”
Claim · model-written summary
Without BCNU, defoliation did not change reduced-to-oxidized antioxidant ratios.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the absence of BCNU, defoliation did not modify the ratios of reduced/oxidized antioxidants, although it triggered a temporary increase in H 2 O 2 level.”
t0“ryegrass”
Claim · model-written summary
Without BCNU, defoliation temporarily increased hydrogen peroxide.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the absence of BCNU, defoliation did not modify the ratios of reduced/oxidized antioxidants, although it triggered a temporary increase in H 2 O 2 level.”
t0“ryegrass”
The same questions in other papers
pruning · molecular: metabolites · LoliumResults agree
3 papers in the same direction as this paper
- no effect
- no effect
- negative
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.