Abstract
A hydroponic experiment was carried out to study the effects of different concentrations of sulfur(0.01—32 mmol/L) on chlorophyll contents and chlorophyll fluorescence parameters of flue-cured tobacco leaves at maturation stage.Chlorophyll a and chlorophyll b contents of flue-cured tobacco leaves at maturation stage gradually increased with increasing concentrations of sulfur,but differences among the treatments were not significant.Chlorophyll a/b values of flue-cured tobacco leaves at maturation stage had no regular change but chlorophyll a/b values in the 0.01—8 mmol/L concentrations of sulfur were slightly higher than those in the 16 and 32 mmol/L concentrations of sulfur.As the sulfur concentration increasing from 2 to 32 mmol/L,there were decreases in the effective quantum yield(EQY),the maximum quantum yield of PSⅡ photochemistry in the dark-adapted state(Fv/Fm),and the photosynthetic electron transport rate(ETR) of flue-cured tobacco leaves at maturation stage,but increases in nonphotochemical quenching(NPQ),basal quantum yield of nonphotochemical quenching(Fo/Fm),PSⅡ water-splitting apparatus inactivation(Fo/Fv),and the degree of reaction center closure(1-qP).The plastoquinone pool(Fv/2) of flue-cured tobacco leaves at maturation stage in the 2 mmol/L concentration of sulfur was lower than that in the 4 mmol/L concentration of sulfur but higher than those in the 8—32 mmol/L concentrations of sulfur.The curves of Fv/2 of flue-cured tobacco in 8—32 mmol/L concentrations of sulfur were almostly overlapped.The EQY,and ETR of flue-cured tobacco leaves at maturation stage in the 0.01 mmol/L concentration of sulfur were lower than those in the 2—8 mmol/L concentrations of sulfur,but higher than those in the 16—32 mmol/L concentrations of sulfur.The Fv/Fm of flue-cured tobacco leaves at maturation stage in the 0.01 mmol/L concentration of sulfur was lower than those in the 2-4 mmol/L concentrations of sulfur but higer than that in the 32 mmol/L concentration of sulfur.There were not significantly different in the Fv/Fm among the 0.01,8 and 16 mmol/L concentration of sulfur.The curves of 1-qP,Fo/Fm and Fo/Fv of flue-cured tobacco leaves at maturation stage in the 0.01 mmol/L concentration of sulfur were intertvined with 8 and 16 mmol/L concentrations of sulfur and higher than those in the 2—4 mmol/L concentrations of sulfur but lower than those in the 32 mmol/L concentration of sulfur.The NPQ of flue-cured tobacco leaves at maturation stage in the 0.01 mmol/L concentration of sulfur were significantly higher than those in the 2—4 mmol/L concentrations of sulfur.Similarly,the NPQ in the 0.01 mmol/L concentration of sulfur was higer than those in the 8—32 mmol/L concentrations of sulfur at photosynthetic active radiation(PAR) range 0—500 μmol · m-2 · s-1 but lower than those in 8 and 16mmol/L concentrations of sulfur at photosynthetic active radiation over 500μmol · m-2 · s-1.The Fv/2 of flue-cured tobacco leaves at maturation stage in the 0.01 mmol/L concentrations of sulfur was lower than that in the 4 mmol/L concentration of sulfur,but higher than those in the 2 mmol/L and the 8—32 mmol/L concentrations of sulfur.These results suggested that the decreases in the EQY,Fv/Fm,and ETR of flue-cured leaves at maturation stage in the 0.01 mmol/L concentrations of sulfur did not result from a decreased plastoquinone pool,but from an increase in the degree of reaction center closure.In the 16—32 mmol/L concentrations of sulfur,the decreases in EQY,Fv/Fm,and ETR resulted from a combination of increased degree of reaction center closure and a decreased plastoquinone pool.
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Claims 18
Claim · model-written summary
Chlorophyll a and b contents rose with increasing sulfur, although differences were not significant.
- Taxon
- flue-cured tobaccoe0
- Organ / stage
- leaves at maturation stagee0
- Treatment
- increasing concentrations of sulfure0
- Outcome
- Chlorophyll a and chlorophyll b contentse0
- Direction
- increasede0
Not reportedComparator
Verbatim
e0“Chlorophyll a and chlorophyll b contents of flue-cured tobacco leaves at maturation stage gradually increased with increasing concentrations of sulfur,but differences among the treatments were not significant”
Claim · model-written summary
Chlorophyll a/b values showed no regular response to sulfur.
- Taxon
- flue-cured tobaccoe0
- Organ / stage
- leaves at maturation stagee0
- Treatment
- sulfure1
- Outcome
- Chlorophyll a/b valuese0
- Direction
- no regular changee0
Not reportedComparator
Verbatim
e0“Chlorophyll a/b values of flue-cured tobacco leaves at maturation stage had no regular change”
e1“sulfur”
Claim · model-written summary
Chlorophyll a/b was slightly higher at 0.01–8 than at 16 and 32 mmol/L sulfur.
Verbatim
e0“chlorophyll a/b values in the 0.01—8 mmol/L concentrations of sulfur were slightly higher than those in the 16 and 32 mmol/L concentrations of sulfur”
e1“flue-cured tobacco”
Claim · model-written summary
Increasing sulfur from 2 to 32 mmol/L decreased effective quantum yield, Fv/Fm and electron transport rate.
- Taxon
- flue-cured tobaccoe0
- Treatment
- sulfur concentration increasing from 2 to 32 mmol/Le0
- Outcome
- effective quantum yield(EQY),the maximum quantum yield of PSⅡ photochemistry in the dark-adapted state(Fv/Fm),and the photosynthetic electron transport rate(ETR)e0
- Direction
- decreasese0
Not reportedComparator
Verbatim
e0“As the sulfur concentration increasing from 2 to 32 mmol/L,there were decreases in the effective quantum yield(EQY),the maximum quantum yield of PSⅡ photochemistry in the dark-adapted state(Fv/Fm),and the photosynthetic electron transport rate(ETR) of flue-cured tobacco leaves at maturation stage”
Claim · model-written summary
Increasing sulfur from 2 to 32 mmol/L increased NPQ, Fo/Fm and Fo/Fv.
- Taxon
- flue-cured tobaccoe0
- Treatment
- sulfur concentration increasing from 2 to 32 mmol/Le0
- Outcome
- nonphotochemical quenching(NPQ),basal quantum yield of nonphotochemical quenching(Fo/Fm),PSⅡ water-splitting apparatus inactivation(Fo/Fv)e0
- Direction
- increasese0
Not reportedComparator
Verbatim
e0“As the sulfur concentration increasing from 2 to 32 mmol/L,there were decreases in the effective quantum yield(EQY),the maximum quantum yield of PSⅡ photochemistry in the dark-adapted state(Fv/Fm),and the photosynthetic electron transport rate(ETR) of flue-cured tobacco leaves at maturation stage,but increases in nonphotochemical quenching(NPQ),basal quantum yield of nonphotochemical quenching(Fo/Fm),PSⅡ water-splitting apparatus inactivation(Fo/Fv),and the degree of reaction center closure(1-qP)”
Claim · model-written summary
Increasing sulfur from 2 to 32 mmol/L increased reaction center closure.
- Taxon
- flue-cured tobaccoe0
- Treatment
- sulfur concentration increasing from 2 to 32 mmol/Le0
- Outcome
- degree of reaction center closure(1-qP)e0
- Direction
- increasese0
Not reportedComparator
Verbatim
e0“As the sulfur concentration increasing from 2 to 32 mmol/L,there were decreases in the effective quantum yield(EQY),the maximum quantum yield of PSⅡ photochemistry in the dark-adapted state(Fv/Fm),and the photosynthetic electron transport rate(ETR) of flue-cured tobacco leaves at maturation stage,but increases in nonphotochemical quenching(NPQ),basal quantum yield of nonphotochemical quenching(Fo/Fm),PSⅡ water-splitting apparatus inactivation(Fo/Fv),and the degree of reaction center closure(1-qP)”
Claim · model-written summary
At 2 mmol/L sulfur, the plastoquinone pool was lower than at 4 mmol/L but higher than at 8–32 mmol/L.
Verbatim
e0“The plastoquinone pool(Fv/2) of flue-cured tobacco leaves at maturation stage in the 2 mmol/L concentration of sulfur was lower than that in the 4 mmol/L concentration of sulfur but higher than those in the 8—32 mmol/L concentrations of sulfur”
Claim · model-written summary
Plastoquinone pool curves at 8–32 mmol/L sulfur nearly overlapped.
Verbatim
e0“The curves of Fv/2 of flue-cured tobacco in 8—32 mmol/L concentrations of sulfur were almostly overlapped”
Claim · model-written summary
At 0.01 mmol/L sulfur, EQY and ETR were lower than at 2–8 but higher than at 16–32 mmol/L.
Verbatim
e0“The EQY,and ETR of flue-cured tobacco leaves at maturation stage in the 0.01 mmol/L concentration of sulfur were lower than those in the 2—8 mmol/L concentrations of sulfur,but higher than those in the 16—32 mmol/L concentrations of sulfur”
Claim · model-written summary
At 0.01 mmol/L sulfur, Fv/Fm was lower than at 2–4 but higher than at 32 mmol/L.
Verbatim
e0“The Fv/Fm of flue-cured tobacco leaves at maturation stage in the 0.01 mmol/L concentration of sulfur was lower than those in the 2-4 mmol/L concentrations of sulfur but higer than that in the 32 mmol/L concentration of sulfur”
Claim · model-written summary
Fv/Fm did not differ significantly among 0.01, 8 and 16 mmol/L sulfur.
- Taxon
- flue-cured tobaccoe1
- Treatment
- 0.01,8 and 16 mmol/L concentration of sulfure0
- Outcome
- Fv/Fme0
- Direction
- not significantly differente0
Not reportedComparator
Verbatim
e0“There were not significantly different in the Fv/Fm among the 0.01,8 and 16 mmol/L concentration of sulfur”
e1“flue-cured tobacco”
Claim · model-written summary
At 0.01 mmol/L sulfur, 1-qP, Fo/Fm and Fo/Fv exceeded 2–4 mmol/L but were below 32 mmol/L.
Verbatim
e0“The curves of 1-qP,Fo/Fm and Fo/Fv of flue-cured tobacco leaves at maturation stage in the 0.01 mmol/L concentration of sulfur were intertvined with 8 and 16 mmol/L concentrations of sulfur and higher than those in the 2—4 mmol/L concentrations of sulfur but lower than those in the 32 mmol/L concentration of sulfur”
Claim · model-written summary
NPQ at 0.01 mmol/L sulfur was significantly higher than at 2–4 mmol/L.
Verbatim
e0“The NPQ of flue-cured tobacco leaves at maturation stage in the 0.01 mmol/L concentration of sulfur were significantly higher than those in the 2—4 mmol/L concentrations of sulfur”
Claim · model-written summary
At PAR 0–500, NPQ at 0.01 mmol/L sulfur exceeded 8–32 mmol/L.
Verbatim
e0“the NPQ in the 0.01 mmol/L concentration of sulfur was higer than those in the 8—32 mmol/L concentrations of sulfur at photosynthetic active radiation(PAR) range 0—500 μmol · m-2 · s-1”
e1“flue-cured tobacco”
Claim · model-written summary
At PAR over 500, NPQ at 0.01 mmol/L sulfur was lower than at 8 and 16 mmol/L.
Verbatim
e0“lower than those in 8 and 16mmol/L concentrations of sulfur at photosynthetic active radiation over 500μmol · m-2 · s-1”
e1“The NPQ of flue-cured tobacco leaves at maturation stage in the 0.01 mmol/L concentration of sulfur”
Claim · model-written summary
At 0.01 mmol/L sulfur, Fv/2 was lower than at 4 mmol/L and higher than at 2 and 8–32 mmol/L.
Verbatim
e0“The Fv/2 of flue-cured tobacco leaves at maturation stage in the 0.01 mmol/L concentrations of sulfur was lower than that in the 4 mmol/L concentration of sulfur,but higher than those in the 2 mmol/L and the 8—32 mmol/L concentrations of sulfur”
Claim · model-written summary
The authors attribute low-sulfur losses of EQY, Fv/Fm and ETR to greater reaction center closure, not a reduced plastoquinone pool.
Verbatim
e0“the decreases in the EQY,Fv/Fm,and ETR of flue-cured leaves at maturation stage in the 0.01 mmol/L concentrations of sulfur did not result from a decreased plastoquinone pool,but from an increase in the degree of reaction center closure”
Claim · model-written summary
The authors attribute high-sulfur losses of EQY, Fv/Fm and ETR to more reaction center closure and a smaller plastoquinone pool.
Verbatim
e0“In the 16—32 mmol/L concentrations of sulfur,the decreases in EQY,Fv/Fm,and ETR resulted from a combination of increased degree of reaction center closure and a decreased plastoquinone pool”
e1“flue-cured tobacco”
The same questions in other papers
sulfur atom · physiology: pigments · Nicotiana tabacum (tobacco)Results agree
2 papers in the same direction as this paper
- positive
- positive
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.