Hostname: page-component-848d4c4894-8kt4b Total loading time: 0 Render date: 2024-07-07T04:43:19.476Z Has data issue: false hasContentIssue false
  • English
  • Français

Sampling a Poisonous Plant Population: Quantifying Toxic Alkaloids in Tall Larkspur (Delphinium barbeyi) Leaves

Published online by Cambridge University Press:  12 June 2017

Gary D. Manners  and
James A. Pfister
Gary D. Manners*
Affiliation:
USDA, Agric. Res. Ser., Western Regional Res. Ctr., 800 Buchanan St., Albany, CA 94710
James A. Pfister
Affiliation:
USDA, Agric. Res. Ser., Poisonous Plant Res. Lab., 1150 East 1400 North, Logan, UT 84341
*
*Corresponding author. email: gmann@pw.usda.gov.
Get access Rights & Permissions [Opens in a new window]

Abstract

Poisonous plants and noxious weeds are often chemically examined to determine concentrations of secondary metabolites which are responsible for their toxic or biological activity. This study examined sample size requirements and sample methods necessary to quantify accurately the concentrations of individual and total toxic alkaloids in two tall larkspur populations. A high performance liquid chromatography analytical method was utilized to determine toxic alkaloid concentrations in all leaves from three individual plant stems and leaves from the remaining stems (remainder) from each of 50 plants in each population. To obtain high precision in quantifying toxic alkaloids in the larkspur populations (within 2.5 to 5% of the population mean, 0.95 confidence), very large numbers of samples (>50–200) were required. However, lower precision (within 10% of the population mean, 0.90–0.95 confidence) required only 20 samples. Similarly, testing parameters relating to toxin concentration in tall larkspur populations within 5 or 10% of the population mean also required hundreds of samples at power levels of 0.95 and α-levels of 0.05. Relaxing power and α-level requirements to 0.80 and 0.1 respectively, reduced sample size to about 30. The means obtained by four different sampling methods were similar (P>0.05). Alkaloid concentrations in leaf samples from single stems were highly correlated to whole-plant leaf (remainder) samples (r2≥0.76), indicating that harvesting leaves from single stems provided representative samples of the entire plant. The results indicate the difficulty in obtaining accurate information about toxins in poisonous plant populations for risk assessment by livestock producers or extension agents and demonstrate the necessity for efficient analytical methodology. Researchers evaluating concentrations of plant compounds in other weeds or toxic plants should consider variability, sampling procedure, and sample size before experiments begin.

Keywords

Tall larkspur, Delphinium barbeyi Huth. ♯ DELBAPoisonous plantsnoxious weedssample sizetoxic alkaloidsmethyllycaconitine
Type
Physiology, Chemistry, and Biochemistry
Information
Weed Science , Volume 44 , Issue 4 , December 1996 , pp. 782 - 788
Copyright
Copyright © 1996 by the Weed Science Society of America 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Literature Cited

Barrett, J. P. and Goldsmith, L. 1976. When is n sufficiently large? Am. Stat. 30: 67–70.Google Scholar
Desu, M. M. and Raghavarao, D. 1990. Sample size methodology. Academic Press, Inc., San Diego, CA. pp. 7–12.Google Scholar
Gardner, D. R., Manners, G. D., Ralphs, M. H., and Pfister, J. A. (In press). Quantitative analysis of diterpenoid alkaloids in larkspur (Delphinium spp.) by Fourier transform infrared spectroscopy. Photochem Anal. Google Scholar
Gershenzon, P. 1984. Changes in the levels of plant secondary metabolites under water and nutrient stress. Pages 273–321 in Phytochemical adaptations to stress, Timmerman, B.N., ed. Plenum Press, NY.Google Scholar
Johnson, A. E., Molyneux, R. J., and Merrill, G. B. 1985. Chemistry of toxic range plants. Variation in pyrrolidine alkaloid content of Senecio, Amsinckia, and Crotalaria species. J. Agric. Food Chem. 33: 50–55.Google Scholar
Keeler, R. F., Van Kampen, K. R., and James, L. F. 1978. Effects of poisonous plants on livestock. Academic Press, New York. pp. 13–21.Google Scholar
Kent, M. and Coker, P. 1992. Vegetation description and analysis. CRC Press, Ann Arbor. pp. 52–54.Google Scholar
Lemeshow, S. and Levy, P. S. 1991. Sampling of populations: methods and applications. John Wiley & Sons, Inc., New York. pp. 37–40.Google Scholar
Manners, G. D., Panter, K. E., Ralphs, M. H., Pfister, J. A., and Olsen, J. D. 1993. The occurrence and toxic evaluation of norditerpenoid alkaloids in the tall larkspurs (Delphinium spp.). J. Agric. Food Chem. 41: 96–100.CrossRefGoogle Scholar
Manners, G. D. and Pfister, J. A. 1993. Normal phase liquid chromatographic analysis of toxic norditerpenoid alkaloids. Phytochem. Anal. 4: 14–18.Google Scholar
Mitchell, J. E. 1993. The rangelands of Colorado. Rangelands 15: 213–219.Google Scholar
Molyneux, R. J. and Johnson, A. E. 1984. Extraordinary levels of production of pyrrolizidine alkaloids in Senecio riddellii . J. Nat. Prod. 47: 1030–1032.Google Scholar
Mueller-Dombois, D. and Ellenberg, H. 1974. Aims and methods of vegetation ecology. J. Wiley & Sons, New York. pp. 90–108.Google Scholar
Neter, J. and Wasserman, W. 1974. Applied linear statistical models. Richard D. Irwin, Inc., Homewood, Illinois. pp. 57–60.Google Scholar
Pfister, J. A., Manners, G. D., Gardner, D. R., and Ralphs, M. H. 1994. Toxic alkaloid levels in tall larkspur (Delphinium barbeyi) in western Colorado. J. Range Manage. 47: 355–358.Google Scholar
Pfister, J. A., Molyneux, R. J., and Baker, D. C. 1992. Pyrrolizidine alkaloid content of houndstongue (Cynoglossum officinale L.). J. Range Manage. 45: 254–256.Google Scholar
Pfister, J. A., Manners, G. D., Ralphs, M. H., Hong, Z. X., and Lane, M. A. 1988 Effects of phenology, site and rumen fill on tall larkspur consumption by cattle. J. Range Manage. 41: 509–513.Google Scholar
Ralphs, M. H., Olsen, J. D., Pfister, J. A., and Manners, G. D. 1988. Plant-animal interactions in larkspur poisoning in cattle. J. Anim. Sci. 66: 2334–2342.Google Scholar
Ralphs, M. H. and Williams, M. C. 1988. Alkaloid response to defoliation of velvet lupine (Lupinus leucophyllus). Weed Technol. 2: 429–432.Google Scholar
Rosenthal, G. A. and Berenbaum, M. R. 1991. Herbivores: their interactions with secondary plant metabolites. 2nd Ed. Academic Press, New York. pp. 198–206.Google Scholar
Steel, R.G.D. and Torrie, J. H. 1980. Principles and procedures of statistics. 2nd Ed. McGraw-Hill Book Company, New York. p. 37.Google Scholar
Williams, B. 1978. A sampler on sampling. John Wiley & Sons, Inc., New York. pp. 219–220.Google Scholar