Diurnal cycle of sparteine production in Lupinus arcticus

• Published in: Canadian Journal of Botany
• Main Authors: Sharam, Gregory J., Turkington, Roy
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2005
• Subjects: Plant Science; Arctic; Yukon
• Online Access: http://dx.doi.org/10.1139/b05-104; http://www.nrcresearchpress.com/doi/full-xml/10.1139/b05-104; http://www.nrcresearchpress.com/doi/pdf/10.1139/b05-104

Sparteine is a neurological toxin found in arctic lupine ( Lupinus arcticus S. Wats.) and is probably used as a defensive chemical to deter herbivory, particularly by snowshoe hares ( Lepus americanus Erxleben). Lupine leaves were collected in southwestern Yukon at 2 h intervals for 2 consecutive days at the peak of the growing season (24–25 June), and their sparteine was extracted and compared with a standard using gas chromatography. A significant daily cycle of sparteine in leaf material was observed, with maximum concentrations occurring during the night and minimum during the afternoon. This may be a temporally optimal response to higher levels of hare herbivory that occur at night.