Abstract
The effects of calcium in the propensity to generate superoxide radical and to form ethylene from ACC were investigated with electron-paramagnetic-resonance spectroscopy. (1). The rate of ethylene formation from ACC, superoxide radical production and membrane fluidity were decreased by treatment with exogenous Ca~(2+) (10~(-1) mol /L), but during senescence the opposite effects were observed by endogenous Ca~(2+) of chloroplasts, isolated from wheat seedlings irrigated with Ca~(2+) (10~(-1) mol/L). (2). The effects of endogenous Ca~(2+) concentration in increasing O_~- and ethylene production were inhibited by CaM antagonists, such as phenothiazine (50 μmol / L) and W_7 (50 μmol / L), and promoted by exogenous linoleic acid, which was considered an endogenous Ca~(2+) ionophore. Linoleic acid was probably the precursor of ethylene, but much less ethylene was produced from it than from ACC. O_2~- levels was positively correlated to ethylene production regulated by endogenous Ca~(2+)(r=0.941). These results implied that exogenous Ca~(2+) may affect membrane state, and hence change the configuration of ethylene forming enzyme or decrease O_2~- production and inhibit the conversion of ACC to ethylene. These also suggested that during senescence internalized Ca~(2+) may induce the increase of superoxide radical production, and then enhance the ethylene formation from its precursor. According to above findings, lipid peroxidation caused by O_2~- and other activated oxygen play a key role in triggering senescence in chloroplasts.
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Claims 5
Claim · model-written summary
Exogenous calcium decreased ethylene formation, superoxide production, and membrane fluidity.
- Taxon
- Wheat
Triticum aestivumt0 - Treatment
- exogenous Ca~(2+) (10~(-1) mol /L)e0
- Outcome
- ethylene formation from ACC, superoxide radical production and membrane fluiditye0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The rate of ethylene formation from ACC, superoxide radical production and membrane fluidity were decreased by treatment with exogenous Ca~(2+) (10~(-1) mol /L)”
t0“Wheat”
Claim · model-written summary
Endogenous calcium increased ethylene formation, superoxide production, and membrane fluidity during senescence.
- Taxon
- wheatTriticum aestivume0
- Organ / stage
- senescencee0
- Treatment
- Ca~(2+) (10~(-1) mol/L)e0
- Outcome
- opposite effectse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“during senescence the opposite effects were observed by endogenous Ca~(2+) of chloroplasts, isolated from wheat seedlings irrigated with Ca~(2+) (10~(-1) mol/L)”
Claim · model-written summary
CaM antagonists inhibited calcium-related increases in superoxide and ethylene.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- CaM antagonistse0
- Outcome
- O_~- and ethylene productione0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The effects of endogenous Ca~(2+) concentration in increasing O_~- and ethylene production were inhibited by CaM antagonists, such as phenothiazine (50 μmol / L) and W_7 (50 μmol / L)”
t0“Wheat”
Claim · model-written summary
Linoleic acid promoted calcium-related increases in superoxide and ethylene.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- exogenous linoleic acide0
- Outcome
- promotede0
- Direction
- promotede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“promoted by exogenous linoleic acid”
t0“Wheat”
Claim · model-written summary
Superoxide levels correlated positively with ethylene production.
- Taxon
- WheatTriticum aestivumt0
- Compound
- O_2~-e0
- Outcome
- ethylene productione0
- Direction
- positively correlatede0
- Value
- r=0.941e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O_2~- levels was positively correlated to ethylene production regulated by endogenous Ca~(2+)(r=0.941)”
t0“Wheat”
The same questions in other papers
calcium atom · physiology: oxidative · Triticum aestivum (wheat)Positive and negative results
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- positive
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See all 11 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.