Abstract
Thirty days old rice plants grown under low and moderate light conditions were transferred to full sunlight to observe the extent of photoinhibitory damage and protective mechanism, and the relationship between xanthophyll cycle and nonphotochemical quenching (qN) under changing light environment. Control plants (low, moderate and sun grown) exhibited similar Fv/Fm ratio, indicating similar photosynthetic efficiency prior to light stress. On exposure to the high light treatment, low light grown plants exhibited faster and higher degree of photoinhibition compared to moderate and high light grown plants. Moderate and high light grown plants showed relatively less photoinhibition and also showed higher qN, indicating better capacity of energy dissipation. Increase in qN in moderate light and sun grown plants was accompanied by conversion of violaxanthin (V) to antheraxanthin (A) and zeaxanthin (Z) indicating operation of Z-dependent thermal dissipation. Rice plants fed with ascorbate (AsA), a stimulator of the de-epoxidation state of V to Z, showed higher Fv/Fm ratio and qN than the plants fed with dithiothreitol (DTT) an inhibitor of xanthophyll cycle. This indicated that an increased amount of energy reached PS II reaction centre, due to absence of A and Z formation, thereby causing greater damage to photosynthesis in DTT fed rice plants. The present data confirmed the relationship between qN and Z in dissipating the excess light energy, thereby protecting plants against photodamage.
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Claims 8
Claim · model-written summary
Before stress, plants grown under low, moderate and sun light had similar Fv/Fm.
- Taxon
- rice
Oryza sativat0 - Outcome
- Fv/Fm ratioe0
- Direction
- similare0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Control plants (low, moderate and sun grown) exhibited similar Fv/Fm ratio, indicating similar photosynthetic efficiency prior to light stress”
t0“rice (Oryza sativa L.) plants”
Claim · model-written summary
After high light exposure, low-light-grown rice had faster and greater photoinhibition than moderate- and high-light-grown plants.
- Taxon
- riceOryza sativat0
- Material
- low light grown plantse0
- Treatment
- high light treatmente0
- Outcome
- photoinhibitione0
- Direction
- faster and highere0
- Comparator
- moderate and high light grown plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“On exposure to the high light treatment, low light grown plants exhibited faster and higher degree of photoinhibition compared to moderate and high light grown plants”
t0“rice (Oryza sativa L.) plants”
Claim · model-written summary
Moderate- and high-light-grown rice showed less photoinhibition.
- Taxon
- riceOryza sativat0
- Material
- Moderate and high light grown plantse0
- Outcome
- photoinhibitione0
- Direction
- lesse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Moderate and high light grown plants showed relatively less photoinhibition and also showed higher qN”
t0“rice (Oryza sativa L.) plants”
Claim · model-written summary
Moderate- and high-light-grown rice showed higher nonphotochemical quenching.
- Taxon
- riceOryza sativat0
- Material
- Moderate and high light grown plantse0
- Outcome
- qNe0
- Direction
- highere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Moderate and high light grown plants showed relatively less photoinhibition and also showed higher qN”
t0“rice (Oryza sativa L.) plants”
Claim · model-written summary
In moderate- and sun-grown rice, increased quenching accompanied conversion of violaxanthin to antheraxanthin and zeaxanthin.
- Taxon
- riceOryza sativat0
- Compound
- violaxanthin (V)e0
- Outcome
- qNe0
- Direction
- Increasee0
- Qualifier
- conversion of violaxanthin (V) to antheraxanthin (A) and zeaxanthin (Z)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increase in qN in moderate light and sun grown plants was accompanied by conversion of violaxanthin (V) to antheraxanthin (A) and zeaxanthin (Z)”
t0“rice (Oryza sativa L.) plants”
Claim · model-written summary
Ascorbate-fed rice had higher Fv/Fm than dithiothreitol-fed rice.
- Taxon
- RiceOryza sativae0
- Treatment
- ascorbate (AsA)e0
- Outcome
- Fv/Fm ratioe0
- Direction
- highere0
- Comparator
- dithiothreitol (DTT)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rice plants fed with ascorbate (AsA), a stimulator of the de-epoxidation state of V to Z, showed higher Fv/Fm ratio and qN than the plants fed with dithiothreitol (DTT) an inhibitor of xanthophyll cycle”
Claim · model-written summary
Ascorbate-fed rice had higher quenching than dithiothreitol-fed rice.
- Taxon
- RiceOryza sativae0
- Treatment
- ascorbate (AsA)e0
- Outcome
- qNe0
- Direction
- highere0
- Comparator
- dithiothreitol (DTT)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rice plants fed with ascorbate (AsA), a stimulator of the de-epoxidation state of V to Z, showed higher Fv/Fm ratio and qN than the plants fed with dithiothreitol (DTT) an inhibitor of xanthophyll cycle”
Claim · model-written summary
The authors inferred that absent antheraxanthin and zeaxanthin formation increased energy at PS II and damaged photosynthesis in DTT-fed rice.
- Taxon
- riceOryza sativae0
- Treatment
- DTTe0
- Outcome
- greater damage to photosynthesise0
- Qualifier
- absence of A and Z formatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“an increased amount of energy reached PS II reaction centre, due to absence of A and Z formation, thereby causing greater damage to photosynthesis in DTT fed rice plants”
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See all 47 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.