Abstract
BACKGROUND: The stimulatory effect of CO2 on ethylene evolution in plants is known, but the extent to which ethylene controls photosynthesis is not clear. Studies on the effects of ethylene on CO2 metabolism have shown conflicting results. Increase or inhibition of photosynthesis by ethylene has been reported. To understand the physiological processes responsible for ethylene-mediated changes in photosynthesis, stomatal and mesophyll effects on photosynthesis and ethylene biosynthesis in response to ethephon treatment in mustard (Brassica juncea) cultivars differing in photosynthetic capacity were studied. RESULTS: The effects of ethephon on photosynthetic rate (PN), stomatal conductance (gS), carbonic anhydrase (CA) activity, 1-aminocyclopropane carboxylic acid synthase (ACS) activity and ethylene evolution were similar in both the cultivars. Increasing ethephon concentration up to 1.5 mM increased PN, gS and CA maximally, whereas 3.0 mM ethephon proved inhibitory. ACS activity and ethylene evolution increased with increasing concentrations of ethephon. The corresponding changes in gs and CA activity suggest that the changes in photosynthesis in response to ethephon were triggered by altered stomatal and mesophyll processes. Stomatal conductance changed in parallel with changes in mesophyll photosynthetic properties. In both the cultivars ACS activity and ethylene increased up to 3.0 mM ethephon, but 1.5 mM ethephon caused maximum effects on photosynthetic parameters. CONCLUSION: These results suggest that ethephon affects foliar gas exchange responses. The changes in photosynthesis in response to ethephon were due to stomatal and mesophyll effects. The changes in gS were a response maintaining stable intercellular CO2 concentration (Ci) under the given treatment in both the cultivars. Also, the high photosynthetic capacity cultivar, Varuna responded less to ethephon than the low photosynthetic capacity cultivar, RH30. The photosynthetic capacity of RH30 increased with the increase in ethylene evolution due to 1.5 mM ethephon application.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 10
Claim · model-written summary
Ethephon effects on photosynthetic rate, stomatal conductance and carbonic anhydrase activity were similar in both cultivars.
- Taxon
- Brassica juncea
Brassica junceat0 - Treatment
- ethephone0
- Outcome
- photosynthetic rate (PN), stomatal conductance (gS), carbonic anhydrase (CA) activitye0
- Direction
- similare0
- Qualifier
- both the cultivarse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The effects of ethephon on photosynthetic rate (PN), stomatal conductance (gS), carbonic anhydrase (CA) activity, 1-aminocyclopropane carboxylic acid synthase (ACS) activity and ethylene evolution were similar in both the cultivars.”
t0“Brassica juncea”
Claim · model-written summary
Ethephon effects on ACS activity and ethylene evolution were similar in both cultivars.
- Taxon
- Brassica junceaBrassica junceat0
- Treatment
- ethephone0
- Outcome
- 1-aminocyclopropane carboxylic acid synthase (ACS) activity and ethylene evolutione0
- Direction
- similare0
- Qualifier
- both the cultivarse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The effects of ethephon on photosynthetic rate (PN), stomatal conductance (gS), carbonic anhydrase (CA) activity, 1-aminocyclopropane carboxylic acid synthase (ACS) activity and ethylene evolution were similar in both the cultivars.”
t0“Brassica juncea”
Claim · model-written summary
Increasing ethephon up to 1.5 mM maximally increased PN, gS and CA.
- Taxon
- Brassica junceaBrassica junceat0
- Treatment
- ethephon concentration up to 1.5 mMe0
- Outcome
- PN, gS and CAe0
- Direction
- increasede0
- Qualifier
- maximallye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing ethephon concentration up to 1.5 mM increased PN, gS and CA maximally”
t0“Brassica juncea”
Claim · model-written summary
3.0 mM ethephon inhibited PN, gS and CA.
- Taxon
- Brassica junceaBrassica junceat0
- Treatment
- 3.0 mM ethephone0
- Outcome
- PN, gS and CAe0
- Direction
- inhibitorye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing ethephon concentration up to 1.5 mM increased PN, gS and CA maximally, whereas 3.0 mM ethephon proved inhibitory.”
t0“Brassica juncea”
Claim · model-written summary
Increasing ethephon increased ACS activity and ethylene evolution, up to 3.0 mM in both cultivars.
- Taxon
- Brassica junceaBrassica junceat0
- Treatment
- increasing concentrations of ethephone0
- Outcome
- ACS activity and ethylene evolutione0
- Direction
- increasede0
- Qualifier
- up to 3.0 mM ethephone1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ACS activity and ethylene evolution increased with increasing concentrations of ethephon.”
e1“In both the cultivars ACS activity and ethylene increased up to 3.0 mM ethephon”
t0“Brassica juncea”
Claim · model-written summary
The authors attribute ethephon-induced photosynthesis changes to stomatal and mesophyll processes.
- Taxon
- Brassica junceaBrassica junceat0
- Treatment
- ethephone0
- Outcome
- photosynthesise0
- Qualifier
- altered stomatal and mesophyll processese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the changes in photosynthesis in response to ethephon were triggered by altered stomatal and mesophyll processes.”
t0“Brassica juncea”
Claim · model-written summary
Stomatal conductance changed in parallel with mesophyll photosynthetic properties.
- Taxon
- Brassica junceaBrassica junceat0
- Organ / stage
- mesophylle0
- Outcome
- Stomatal conductancee0
- Qualifier
- in parallel with changes in mesophyll photosynthetic propertiese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Stomatal conductance changed in parallel with changes in mesophyll photosynthetic properties.”
t0“Brassica juncea”
Claim · model-written summary
Changes in gS maintained stable intercellular CO2 concentration under treatment in both cultivars.
- Taxon
- Brassica junceaBrassica junceat0
- Outcome
- intercellular CO2 concentration (Ci)e0
- Direction
- stablee0
- Qualifier
- changes in gSe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The changes in gS were a response maintaining stable intercellular CO2 concentration (Ci) under the given treatment in both the cultivars.”
t0“Brassica juncea”
Claim · model-written summary
Varuna responded less to ethephon than RH30.
- Taxon
- Brassica junceaBrassica junceat0
- Material
- Varunae0
- Treatment
- ethephone0
- Outcome
- responded lesse0
- Direction
- lesse0
- Comparator
- RH30e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the high photosynthetic capacity cultivar, Varuna responded less to ethephon than the low photosynthetic capacity cultivar, RH30.”
t0“Brassica juncea”
Claim · model-written summary
RH30 photosynthetic capacity increased alongside increased ethylene evolution following 1.5 mM ethephon application.
- Taxon
- Brassica junceaBrassica junceat0
- Material
- RH30e0
- Treatment
- 1.5 mM ethephon applicatione0
- Compound
- ethylenee0
- Outcome
- photosynthetic capacitye0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The photosynthetic capacity of RH30 increased with the increase in ethylene evolution due to 1.5 mM ethephon application.”
t0“Brassica juncea”
The same questions in other papers
(2-chloroethyl)phosphonic acid · physiology: photosynthesis · Brassica juncea (Indian mustard)Results agree
4 papers in the same direction as this paper
- positive
- positive
- positive
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.