Location: Poisonous Plant Research
Title: Geographical and seasonal variation in water hemlock (Cicuta maculata) toxinsAuthor
Stonecipher, Clinton - Clint | |
Welch, Kevin | |
Lee, Stephen | |
Cook, Daniel | |
Pfister, James |
Submitted to: Biochemical Systematics and Ecology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/6/2020 Publication Date: 4/1/2020 Publication URL: https://handle.nal.usda.gov/10113/6830194 Citation: Stonecipher, C.A., Welch, K.D., Lee, S.T., Cook, D., Pfister, J.A. 2020. Geographical and seasonal variation in water hemlock (Cicuta maculata) toxins. Biochemical Systematics and Ecology. 89. https://doi.org/10.1016/j.bse.2020.104012. DOI: https://doi.org/10.1016/j.bse.2020.104012 Interpretive Summary: Water hemlock plants are typically found in wet areas and are toxic to all species of livestock. The objective of this study was to evaluate the variation in toxic compounds in water hemlock populations across western North America. Toxin concentrations varied among the six collection locations and among plant parts. Tubers contained the highest toxin concentrations of all plant parts. Green seeds contained the second most abundant toxic concentrations. Toxin concentrations were also compared in different plant parts at several different growth stages over the growing season. Toxin concentrations in the tubers increased until the green seed stage whereupon the concentrations decreased as the seeds matured and the plant began to senesce. Concentrations of secondary compounds in the stems were consistent with the optimal defense theory in which secondary compounds were higher in stems in earlier development stages compared to later stages and concentrations in seeds were higher than other above ground parts. The toxic compounds are found in all plant parts, with tubers posing the most significant risk of livestock poisoning. Results presented in this study suggest that the toxic risk to livestock likely does not differ between water hemlock populations across western North America under similar circumstances of ingestion. Technical Abstract: Water hemlock (Cicuta spp.) plants are typically found in wet areas and are toxic to all species of livestock. The toxic components in water hemlock are C17 polyacetylenes, with cicutoxin being the most studied. The objective of this study was to evaluate the variation in cicutoxin and total C17 polyacetylene compounds in water hemlock populations across western North America. Cicutoxin and total C17 polyacetylene concentrations varied among the six collection locations and among plant parts. Tubers contained the highest cicutoxin and total C17 polyacetylene concentrations of all plant parts. Green seeds contained the second most abundant total C17 polyacetylene concentrations. Total C17 polyacetylene and cicutoxin concentrations were also compared in different plant parts at several different phenological stages over the growing season. Cicutoxin and total C17 polyacetylene concentrations in the tubers increased until the green seed stage whereupon the concentrations decreased as the seeds matured and the plant began to senesce. Concentrations of secondary compounds in the stems were consistent with the optimal defense theory in which secondary compounds were higher in stems in earlier development stages compared to later stages and concentrations in seeds were higher than other above ground parts. The toxic compounds are found in all plant parts, with tubers posing the most significant risk of livestock poisoning. Results presented in this study suggest that the toxic risk to livestock likely does not differ between water hemlock (Cicuta maculata) populations across western North America under similar circumstances of ingestion. |