Abstract
ABSTRACT Mechanisms preventing oxidative burst in cells exposed to high metal concentrations are crucial for cell survival. In this report, sunflower (Helianthus annuus L.) was used as a model species to investigate: (a) how cadmium (Cd) affects plant defense pathways (in particular, those involved in preventing oxidative stress), and (b) whether antioxidative enzymes of plants and of in vitro cell culture (calluses) have similar responses to Cd exposure. For this experiment, plants (grown hydroponically on Long Ashton medium) and calluses (grown on Murashige and Skoog medium) were exposed for three weeks to different Cd concentrations (0, 5, 50, and 500 μ M). Solute and electrolyte leakage increased significantly with the increase in Cd concentration in the external medium and in exposed leaves, and less in exposed calluses. Cadmium exposure also reduced significantly soluble protein contents in both leaves and calluses. The activities of catalase and peroxidase decreased significantly in 50 and 500 μ M-exposed leaves compared with the control, but increased in 5 μ M-exposed calluses, decreasing in the calluses exposed 500 μ M Cd. The decrease in antioxidative enzymes activities is congruent with the decrease in membrane integrity and suggests that calluses develop antioxidant mechanisms that respond better to Cd stress than do leaves. On average, 100% of plants exposed for 21 d to 500 μ M and 95% of plants exposed for 45 d to 50 μ M Cd were dead. After 45 d, only 53% of 50 μ M-exposed calluses had died. These surviving calluses were maintained on 50 μ M for six months. Six-month-old exposed calluses had higher activities of peroxidase and catalase when compared with control calluses, as well as lower membrane degradation. These data show that calluses are more tolerant than plants to Cd exposure, and that antioxidant mechanisms under Cd exposure may differ between the two cell systems and vary with time.
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Claims 14
Claim · model-written summary
Cadmium increased solute and electrolyte leakage in sunflower leaves.
- Taxon
- sunflower
Helianthus annuust0 - Organ / stage
- leavese0
- Treatment
- Cd concentratione0
- Outcome
- Solute and electrolyte leakagee0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Solute and electrolyte leakage increased significantly with the increase in Cd concentration in the external medium and in exposed leaves, and less in exposed calluses.”
t0“Sunflower”
Claim · model-written summary
Cadmium increased solute and electrolyte leakage less in calluses than leaves.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- callusese0
- Treatment
- Cd concentratione0
- Outcome
- Solute and electrolyte leakagee0
- Direction
- lesse0
- Comparator
- leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Solute and electrolyte leakage increased significantly with the increase in Cd concentration in the external medium and in exposed leaves, and less in exposed calluses.”
t0“Sunflower”
Claim · model-written summary
Cadmium significantly reduced soluble protein contents in leaves.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- leavese0
- Treatment
- Cadmium exposuree0
- Outcome
- soluble protein contentse0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cadmium exposure also reduced significantly soluble protein contents in both leaves and calluses.”
t0“Sunflower”
Claim · model-written summary
Cadmium significantly reduced soluble protein contents in calluses.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- callusese0
- Treatment
- Cadmium exposuree0
- Outcome
- soluble protein contentse0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cadmium exposure also reduced significantly soluble protein contents in both leaves and calluses.”
t0“Sunflower”
Claim · model-written summary
Catalase activity fell in leaves exposed to 50 and 500 μ M cadmium.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- leavese0
- Treatment
- 50 and 500 μ M-exposede0
- Outcome
- catalasee0
- Direction
- decreasede0
- Comparator
- the controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The activities of catalase and peroxidase decreased significantly in 50 and 500 μ M-exposed leaves compared with the control, but increased in 5 μ M-exposed calluses, decreasing in the calluses exposed 500 μ M Cd.”
t0“Sunflower”
Claim · model-written summary
Peroxidase activity fell in leaves exposed to 50 and 500 μ M cadmium.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- leavese0
- Treatment
- 50 and 500 μ M-exposede0
- Outcome
- peroxidasee0
- Direction
- decreasede0
- Comparator
- the controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The activities of catalase and peroxidase decreased significantly in 50 and 500 μ M-exposed leaves compared with the control, but increased in 5 μ M-exposed calluses, decreasing in the calluses exposed 500 μ M Cd.”
t0“Sunflower”
Claim · model-written summary
Catalase and peroxidase activity increased in calluses exposed to 5 μ M cadmium.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- callusese0
- Treatment
- 5 μ M-exposede0
- Outcome
- catalase and peroxidasee0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The activities of catalase and peroxidase decreased significantly in 50 and 500 μ M-exposed leaves compared with the control, but increased in 5 μ M-exposed calluses, decreasing in the calluses exposed 500 μ M Cd.”
t0“Sunflower”
Claim · model-written summary
Catalase and peroxidase activity decreased in calluses exposed to 500 μ M cadmium.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- callusese0
- Treatment
- 500 μ M Cde0
- Outcome
- catalase and peroxidasee0
- Direction
- decreasinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The activities of catalase and peroxidase decreased significantly in 50 and 500 μ M-exposed leaves compared with the control, but increased in 5 μ M-exposed calluses, decreasing in the calluses exposed 500 μ M Cd.”
t0“Sunflower”
Claim · model-written summary
All plants exposed to 500 μ M cadmium for 21 days died.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- 500 μ Me0
- Outcome
- plants exposed for 21 d to 500 μ M and 95% of plants exposed for 45 d to 50 μ M Cd were deade0
- Value
- 100%e0
- Qualifier
- 21 de0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“On average, 100% of plants exposed for 21 d to 500 μ M and 95% of plants exposed for 45 d to 50 μ M Cd were dead.”
t0“Sunflower”
Claim · model-written summary
95% of plants exposed to 50 μ M cadmium for 45 days died.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- 50 μ M Cde0
- Outcome
- plants exposed for 45 d to 50 μ M Cd were deade0
- Value
- 95%e0
- Qualifier
- 45 de0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“On average, 100% of plants exposed for 21 d to 500 μ M and 95% of plants exposed for 45 d to 50 μ M Cd were dead.”
t0“Sunflower”
Claim · model-written summary
53% of calluses exposed to 50 μ M cadmium died after 45 days.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- callusese0
- Treatment
- 50 μ M-exposede0
- Outcome
- calluses had diede0
- Value
- 53%e0
- Qualifier
- 45 de0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After 45 d, only 53% of 50 μ M-exposed calluses had died.”
t0“Sunflower”
Claim · model-written summary
Six-month cadmium-exposed calluses had higher peroxidase activity than controls.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- callusese0
- Outcome
- peroxidasee0
- Direction
- highere0
- Qualifier
- Six-month-olde0
- Comparator
- control callusese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Six-month-old exposed calluses had higher activities of peroxidase and catalase when compared with control calluses, as well as lower membrane degradation.”
t0“Sunflower”
Claim · model-written summary
Six-month cadmium-exposed calluses had higher catalase activity than controls.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- callusese0
- Outcome
- catalasee0
- Direction
- highere0
- Qualifier
- Six-month-olde0
- Comparator
- control callusese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Six-month-old exposed calluses had higher activities of peroxidase and catalase when compared with control calluses, as well as lower membrane degradation.”
t0“Sunflower”
Claim · model-written summary
Six-month cadmium-exposed calluses had lower membrane degradation than controls.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- callusese0
- Outcome
- membrane degradatione0
- Direction
- lowere0
- Qualifier
- Six-month-olde0
- Comparator
- control callusese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Six-month-old exposed calluses had higher activities of peroxidase and catalase when compared with control calluses, as well as lower membrane degradation.”
t0“Sunflower”
The same questions in other papers
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3 papers in the same direction as this paper · 4 in the opposite direction
- positive
- positive
- positive
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See all 8 papers →heavy metal · physiology: osmolytes · Helianthus annuus (common sunflower)Results agree
5 papers in the same direction as this paper
- negative
- negative
- negative
2 papers more in this group
See all 6 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.