Methyl mercury toxicity in plant cultures: modification of resistance and demethylation by light and/or 2,4-dichlorophenoxyacetic acid
Cultures of Daucus carota, Ca-68-10, and Lactuca sativa, Le-67, were grown at increasing methyl mercury (MeHg) concentrations ranging from initial doses of 0.05 to 5.0 micrograms/ml per day for 4 days with or without 0.15 microgram/ml 2,4-dichlorophenoxyacetic acid (2,4-D) in the presence or absence of light. The presence of 2,4-D interacted with light synergistically in the expression of MeHg toxicity within the whole range of concentrations. Demethylation patterns increased or decreased depending on the species, the 2,4-D concentration in the medium, and methyl mercury concentration used in the treatment. Lettuce was more sensitive to this interaction than carrot. In lettuce, the presence of 2,4-D in the light lowered the concentration of total Hg (or MeHg) required to reduce growth by 50%, about 13 times relative to that in the dark (i.e., it sensitized the cells). In the absence of 2,4-D the pattern was reversed. In carrot the pattern was similar but less pronounced. This suggests that, in these cell populations, MeHg toxicity is partly a hormone-mediated and light-sensitive event.
- Research Organization:
- National Research Council of Canada, Ottawa
- OSTI ID:
- 6271832
- Journal Information:
- Ecotoxicol. Environ. Saf.; (United States), Vol. 13:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HERBS
SENSITIVITY
ACETIC ACID
CARROTS
CHLOROPHYLL
DEALKYLATION
DOSE-RESPONSE RELATIONSHIPS
GENETIC VARIABILITY
LETTUCE
METHYLMERCURY
SYNERGISM
TOXICITY
VISIBLE RADIATION
BIOLOGICAL VARIABILITY
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
ELECTROMAGNETIC RADIATION
FOOD
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
MERCURY COMPOUNDS
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC MERCURY COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHYTOCHROMES
PIGMENTS
PLANTS
PORPHYRINS
PROTEINS
RADIATIONS
VEGETABLES
560300* - Chemicals Metabolism & Toxicology