Abstract
ABSTRACT The objective of the present study was to evaluate the tolerance to cadmium (Cd) of sunflower genotypes grown in greenhouse conditions, and the effectiveness of using photosynthetic parameters as physiological indicators of this tolerance. Seeds of two sunflower genotypes previously identified as tolerant (H358) and Cd-sensitive (AG960) to Cd were used. The seeds were germinated in plastic cups containing plant substrate; after 9 days, the seedlings were transplanted to plastic basins containing a nutrient solution with 0 or 10 µM of Cd, where they remained for 16 days. Samples of the plants were harvested every 5 days. The experiment was carried out in a randomized complete design, using a 4×2×2 factorial arrangement (4 days of grown in a nutrient solution with Cd, 2 sunflower genotypes, and 2 Cd levels) with four replications. Cd stress decreased CO2 net assimilation, stomatal conductance, carboxylation efficiency, photosynthetic pigment contents, potential quantum yield (Fv/Fm), and effective quantum yield of plants of the two evaluated genotypes. The decrease in photosynthetic rates of these plants was caused by both stomatal and non-stomatal limitations. Plants of the AG960 genotype showed more pronounced deleterious effects due to Cd stress than those of the H358 genotype. Thus, CO2 net assimilation rate, stomatal conductance, and chloroplast pigment content are good physiological indicators of sunflower tolerance to Cd and can at least in part, explain the greater tolerance of the H358 genotype to Cd stress when compared to the AG960 genotype.
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Claims 5
Claim · model-written summary
Cadmium stress decreased CO2 assimilation, stomatal conductance and carboxylation efficiency in both sunflower genotypes.
- Taxon
- sunflower
Helianthus annuust0 - Treatment
- Cd stresse0
- Outcome
- CO2 net assimilation, stomatal conductance, carboxylation efficiencye0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cd stress decreased CO2 net assimilation, stomatal conductance, carboxylation efficiency, photosynthetic pigment contents, potential quantum yield (Fv/Fm), and effective quantum yield of plants of the two evaluated genotypes”
t0“SUNFLOWER”
Claim · model-written summary
Cadmium stress decreased pigment content and both quantum yields.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- Cd stresse0
- Outcome
- photosynthetic pigment contents, potential quantum yield (Fv/Fm), and effective quantum yielde0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cd stress decreased CO2 net assimilation, stomatal conductance, carboxylation efficiency, photosynthetic pigment contents, potential quantum yield (Fv/Fm), and effective quantum yield of plants of the two evaluated genotypes”
t0“SUNFLOWER”
Claim · model-written summary
Both stomatal and non-stomatal limitations caused the decline in photosynthesis.
- Taxon
- sunflowerHelianthus annuust0
- Outcome
- decrease in photosynthetic ratese0
- Qualifier
- both stomatal and non-stomatal limitationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The decrease in photosynthetic rates of these plants was caused by both stomatal and non-stomatal limitations”
t0“SUNFLOWER”
Claim · model-written summary
AG960 showed stronger cadmium damage than H358.
- Taxon
- sunflowerHelianthus annuust0
- Material
- AG960e0
- Treatment
- Cd stresse0
- Outcome
- deleterious effectse0
- Direction
- more pronouncede0
- Comparator
- H358e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plants of the AG960 genotype showed more pronounced deleterious effects due to Cd stress than those of the H358 genotype”
t0“SUNFLOWER”
Claim · model-written summary
Assimilation, conductance and pigment content were judged useful indicators of cadmium tolerance.
- Taxon
- sunflowerHelianthus annuust0
- Outcome
- physiological indicators of sunflower tolerance to Cde0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CO2 net assimilation rate, stomatal conductance, and chloroplast pigment content are good physiological indicators of sunflower tolerance to Cd”
t0“SUNFLOWER”
The same questions in other papers
cadmium atom · physiology: gas exchange · Helianthus annuus (common sunflower)Results differ
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cadmium atom · physiology: photosynthesis · Helianthus annuus (common sunflower)Results agree
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- negative
- no effect
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5 papers more in this group
See all 9 papers →heavy metal · physiology: photosynthesis · Helianthus annuus (common sunflower)Results agree
3 papers in the same direction as this paper
- negative
- negative
- negative
heavy metal · physiology: gas exchange · Helianthus annuus (common sunflower)Results agree
3 papers in the same direction as this paper
- negative
- no effect
- 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.