Abstract
The relationship of zinc (Zn) efficiency in rice to differential tolerance of photosynthetic capacity and chloroplast function to low Zn stress was studied using Zn-efficient (IR8192) and Zn-inefficient (Erjiufeng) rice genotypes (Oryza sativa L.). Zinc deficiency caused extensive declines in leaf chlorophyll (Chl) content, ratios of chl a:b, Pn, Fv/Fm and Fv/Fo, indicating that the intrinsic quantum efficiency of the photosystem II (PSII) units was damaged. A greater decline was observed in the inefficient genotype (Erjiufeng) than the efficient genotype (IR8192). The 77 K chl fluorescence emission spectrum revealed that Zn deficiency blocked energy spillover from PSII to PSI and more excitation energy was distributed to PSII in IR8192 than Erjiufeng. The spectrum of Zn-deficient Erjiufeng was completely disordered, implying that the photosynthetic centers were seriously damaged. Electron microscopy showed that Zn deficiency caused a severe damage to the fine structure of chloroplasts, but IR8192 had a better preserved chloroplast ultrastructure as compared with Erjiufeng. These differences may result from the higher levels of the antioxidant enzyme activities and lower oxidant stress level in IR8192. These results indicate that Zn deficiency decreases leaf photosynthetic capacity primarily by reducing the number of PSII units per unit leaf area, and also reducing the photochemical capacity of the remaining PSII units. Therefore, the maintenance of more efficient photochemical capacity under low Zn stress is a key factor for the high Zn efficiency in rice, which may result from less antioxidant damage caused by low Zn to the chloroplast ultrastructure.
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Claims 9
Claim · model-written summary
Zinc deficiency decreased chlorophyll content, chlorophyll a:b, Pn, Fv/Fm and Fv/Fo.
- Taxon
- Oryza sativa L.
Oryza sativae1 - Treatment
- Zinc deficiencye0
- Outcome
- leaf chlorophyll (Chl) content, ratios of chl a:b, Pne0
- Direction
- declinese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Zinc deficiency caused extensive declines in leaf chlorophyll (Chl) content, ratios of chl a:b, Pn, Fv/Fm and Fv/Fo”
e1“rice genotypes (Oryza sativa L.)”
Claim · model-written summary
The inefficient Erjiufeng genotype had greater declines than IR8192 under zinc deficiency.
- Taxon
- Oryza sativa L.Oryza sativae1
- Material
- Erjiufenge0
- Outcome
- greater declinee0
- Direction
- greatere0
- Comparator
- IR8192e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A greater decline was observed in the inefficient genotype (Erjiufeng) than the efficient genotype (IR8192).”
e1“rice genotypes (Oryza sativa L.)”
Claim · model-written summary
Zinc deficiency blocked energy spillover from PSII to PSI.
- Taxon
- Oryza sativa L.Oryza sativae1
- Treatment
- Zn deficiencye0
- Outcome
- energy spillover from PSII to PSIe0
- Direction
- blockede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Zn deficiency blocked energy spillover from PSII to PSI”
e1“rice genotypes (Oryza sativa L.)”
Claim · model-written summary
More excitation energy was distributed to PSII in IR8192 than in Erjiufeng.
- Taxon
- Oryza sativa L.Oryza sativae1
- Material
- IR8192e0
- Outcome
- excitation energy was distributed to PSIIe0
- Direction
- moree0
- Comparator
- Erjiufenge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“more excitation energy was distributed to PSII in IR8192 than Erjiufeng”
e1“rice genotypes (Oryza sativa L.)”
Claim · model-written summary
The fluorescence spectrum of zinc-deficient Erjiufeng was disordered.
- Taxon
- Oryza sativa L.Oryza sativae1
- Material
- Erjiufenge0
- Outcome
- spectrume0
- Direction
- completely disorderede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The spectrum of Zn-deficient Erjiufeng was completely disordered”
e1“rice genotypes (Oryza sativa L.)”
Claim · model-written summary
Zinc deficiency severely damaged chloroplast fine structure.
- Taxon
- Oryza sativa L.Oryza sativae1
- Treatment
- Zn deficiencye0
- Outcome
- fine structure of chloroplastse0
- Direction
- severe damagee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Zn deficiency caused a severe damage to the fine structure of chloroplasts”
e1“rice genotypes (Oryza sativa L.)”
Claim · model-written summary
IR8192 preserved chloroplast ultrastructure better than Erjiufeng.
- Taxon
- Oryza sativa L.Oryza sativae1
- Material
- IR8192e0
- Outcome
- chloroplast ultrastructuree0
- Direction
- better preservede0
- Comparator
- Erjiufenge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“IR8192 had a better preserved chloroplast ultrastructure as compared with Erjiufeng”
e1“rice genotypes (Oryza sativa L.)”
Claim · model-written summary
IR8192 had higher antioxidant enzyme activity and lower oxidant stress than Erjiufeng.
- Taxon
- Oryza sativa L.Oryza sativae1
- Material
- IR8192e0
- Outcome
- antioxidant enzyme activitiese0
- Direction
- highere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“higher levels of the antioxidant enzyme activities and lower oxidant stress level in IR8192”
e1“rice genotypes (Oryza sativa L.)”
Claim · model-written summary
IR8192 had lower oxidant stress than Erjiufeng.
- Taxon
- Oryza sativa L.Oryza sativae1
- Material
- IR8192e0
- Outcome
- oxidant stress levele0
- Direction
- lowere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“higher levels of the antioxidant enzyme activities and lower oxidant stress level in IR8192”
e1“rice genotypes (Oryza sativa L.)”
The same questions in other papers
zinc atom · physiology: photosynthesis · Oryza sativa (rice)Positive and negative results
11 papers in the same direction as this paper · 2 in the opposite direction
This paper is about lacking the nutrient, so it counts the other way round here.
- positive
- positive
- negative
10 papers more in this group
See all 14 papers →zinc atom · soil: physics · Oryza sativa (rice)Results agree
1 paper in the same direction as this paper
This paper is about lacking the nutrient, so it counts the other way round here.
- 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.