Variations in miserotoxin concentration of Columbia milkvetch located in pure lodgepole pine forests were compared to changes in rainfall patterns during the period 1973 to 1976. The substantial increase in precipitation for 1976 was reflected in soil and plant moisture changes and these conditions appeared to induce the formation of higher miserotoxin levels. In addition, a number of secondary miserotoxin peaks were generated during pod development in 1976. Understory light regimes at 12 lodgepole pine sites were determined by chemical actinometry, which expressed duration in direct sun at each plot as a percentage of "full sun" (FS) control. Sites with <15% FS exhibited lower miserotoxin levels than either the 15-35% or >35% FS groups. Miserotoxin levels above 6% predominated in the latter two categories. A positive relationship between light and toxicity was not apparent in the Douglasfir stands where miserotoxin levels remained low. A gas chromatography method was developed to speed up miserotoxin determinations and to screen Columbia milkvetch samples for the presence of free 3-nitropropanol. This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries. The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information. Migrated from OJS platform August 2020
Scholarly peer-reviewed articles published by the Society for Range Management. Access articles on a rolling-window basis from vol. 1, 1948 up to 5 years from the current year. Formerly Journal of Range Management (JRM). More recent content is available by subscription from SRM.