Abstract
A high capacity for accumulation of Mn was reported for sunflower plants. Localization of excess Mn is therefore of special interest for understanding metal tolerance mechanisms in this species. In this study, structural and histochemical alterations caused by Mn accumulation in leaves were investigated in sunflower (Helianthus annuus L. cv. Azar-ghol) plants grown in nutrient solution. In the presence of excess Mn (up to 100 µM) shoot and root accumulated up to 4-5 mg Mn g -1 DW concomitant with an increased activity of peroxidase, but not catalase. Symptoms were observed in mature leaves of plants as small dark-brown to black spots associated with the leaf trichomes. In the short uni- or multi-cellula r leaf hairs the entire trichome was blackened, while there was a blackened basal cell or tip cell in the long linear multi-cellular trichomes. No dark deposition was observed either in the tip or in the base of the spiral multi-cellular trichomes. Epiillumination method revealed a dense dark discoloration of small veins of areoles in mature leaves of Mn treated plants with a high auto-fluorescence, suggesting accumulation of phenolics. Histochemical methods for callose, lipids, lignin and proteins showed no change in Mn treated leaves; while a significant decrease of starch grains was observed using polysaccaride identification test. Bleaching of dark spots by ethanol and lack of auto-fluoresc ence in the locations of leaf trichomes as well as result of histochemical methods for free and bound phenolics suggested strongly that the dark spots are the locations of MnO2 deposits.
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Claims 13
Claim · model-written summary
Shoots accumulated up to 4-5 mg Mn g -1 DW under excess Mn.
- Taxon
- sunflower
Helianthus annuust0 - Treatment
- excess Mn (up to 100 µM)e0
- Outcome
- shoote0
- Direction
- accumulatede0
- Value
- 4-5 mg Mn g -1 DWe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the presence of excess Mn (up to 100 µM) shoot and root accumulated up to 4-5 mg Mn g -1 DW”
t0“SUNFLOWER”
Claim · model-written summary
Roots accumulated up to 4-5 mg Mn g -1 DW under excess Mn.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- excess Mn (up to 100 µM)e0
- Outcome
- root accumulatede0
- Direction
- accumulatede0
- Value
- 4-5 mg Mn g -1 DWe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the presence of excess Mn (up to 100 µM) shoot and root accumulated up to 4-5 mg Mn g -1 DW”
t0“SUNFLOWER”
Claim · model-written summary
Peroxidase activity increased under excess Mn.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- excess Mne1
- Gene
- peroxidasee0
- Outcome
- activity of peroxidasee0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“concomitant with an increased activity of peroxidase, but not catalase.”
t0“SUNFLOWER”
e1“excess Mn (up to 100 µM)”
Claim · model-written summary
Catalase activity did not increase under excess Mn.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“concomitant with an increased activity of peroxidase, but not catalase.”
t0“SUNFLOWER”
e1“excess Mn (up to 100 µM)”
Claim · model-written summary
Mature leaves had dark spots associated with trichomes.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- mature leavese0
- Outcome
- small dark-brown to black spotse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Symptoms were observed in mature leaves of plants as small dark-brown to black spots associated with the leaf trichomes.”
t0“SUNFLOWER”
Claim · model-written summary
Short leaf hairs were entirely blackened.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- short uni- or multi-cellula r leaf hairse0
- Outcome
- entire trichome was blackenede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the short uni- or multi-cellula r leaf hairs the entire trichome was blackened”
t0“SUNFLOWER”
Claim · model-written summary
Long trichomes had a blackened basal or tip cell.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- long linear multi-cellular trichomese0
- Outcome
- blackened basal cell or tip celle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there was a blackened basal cell or tip cell in the long linear multi-cellular trichomes.”
t0“SUNFLOWER”
Claim · model-written summary
Spiral trichomes lacked dark deposition.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- spiral multi-cellular trichomese0
- Outcome
- No dark depositione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No dark deposition was observed either in the tip or in the base of the spiral multi-cellular trichomes.”
t0“SUNFLOWER”
Claim · model-written summary
Small veins in treated mature leaves had dense dark discoloration and high auto-fluorescence.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- mature leavese0
- Treatment
- Mn treatede0
- Outcome
- dense dark discoloration of small veins of areolese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a dense dark discoloration of small veins of areoles in mature leaves of Mn treated plants with a high auto-fluorescence”
t0“SUNFLOWER”
Claim · model-written summary
Callose, lipids and lignin showed no histochemical change in Mn treated leaves.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- Mn treatede0
- Outcome
- callose, lipids, lignine0
- Direction
- no changee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Histochemical methods for callose, lipids, lignin and proteins showed no change in Mn treated leaves”
t0“SUNFLOWER”
Claim · model-written summary
Proteins showed no histochemical change in Mn treated leaves.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- Mn treatede0
- Outcome
- proteinse0
- Direction
- no changee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Histochemical methods for callose, lipids, lignin and proteins showed no change in Mn treated leaves”
t0“SUNFLOWER”
Claim · model-written summary
Starch grains significantly decreased in Mn treated leaves.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- Mn treated leavese1
- Outcome
- starch grainse0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a significant decrease of starch grains was observed”
t0“SUNFLOWER”
e1“Mn treated leaves”
Claim · model-written summary
The dark spots were interpreted as MnO2 deposits.
- Taxon
- sunflowerHelianthus annuust0
- Compound
- MnO2e0
- Outcome
- dark spotse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the dark spots are the locations of MnO2 deposits.”
t0“SUNFLOWER”
The same questions in other papers
manganese atom · physiology: antioxidant enzymes · Helianthus annuus (common sunflower)Positive and negative results
1 in the opposite direction
- positive
manganese atom · molecular: metabolites · Helianthus annuus (common sunflower)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- positive
- negative
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.