Effect of shade on alkaloid content of Lupinus leucophyllus.

Abstract

On a pasture in Washington, USA, with a historically high incidence of crooked calf (lupine-induced arthrogryposis), the north-facing half of each of five plants of Lupinus leucophyllus was shaded by constructing a tent with black 4-mm plastic stretching from the centre of the plant clump over to its north edge. The shading was left in place for 7 days, and thereafter, the shaded and unshaded halves of the lupine plants were harvested at midday, dried and stored at room temperature until analysis. There was no significant effect of the shade on the concentration of the teratogenic alkaloid anagyrine, but a significant difference was observed with 5,6-dehydrolupanine. A significant difference was also observed with unknown alkaloid F and total alkaloids. Given the small sample size, these results suggest further studies on the effects of shade on alkaloid concentration and plant palatability are warranted.