Accumulation of nitrate by annual goldeneye and showy goldeneye

Abstract

Annual goldeneye [Viguiera annua (M.E. Jones) Blake] and showy goldeneye [Viguiera multiflora (Nutt.) Blake], grown in the greenhouse and from the field, were analyzed for cyanide, soluble oxalates, alkaloids, nitro compounds, and nitrate. Both species were investigated for their ability to accumulate toxic levels of nitrate when grown in nutrient solution, or in soils fertilized with ammonium nitrate. Both species tested negative for cyanide, soluble oxalates, nitro compounds, and alkaloids. The plants accumulated toxic levels of nitrate, calculated as KNO3, when grown in nutrient solutions (4 to 5%), greenhouse soil fertilized with ammonium nitrate at 220 kg N/ha (3 to 4%), or from plots fertilized with ammonium nitrate in the field at 66 to 220 kg N/ha (2 to 3%). Annual goldeneye collected near a water tank and salt lick on a New Mexico ranch contained 4.7% nitrate but plants collected at other sites contained only 0.05 to 0.7% nitrate. Goldeneye in the field may accumulate toxic levels of nitrate if rooted on soils heavily contaminated by animal excreta around water tanks, ponds, salt licks, and along frequently used trails. Livestock losses from goldeneye can be reduced or prevented by avoiding the plants and by treating affected animals with methylene blue.