Phytotoxicity, uptake, and distribution of [14C] simazine in Canna hybrida ‘Yellow King Humbert’

Abstract

AbstractPhytoremediation depends on the ability of plants to tolerate and assimilate contaminants. We have been interested in the use of common ornamental plants to ameliorate the impacts of pesticide waste on golf courses and ornamental plant nurseries. This research characterized the interaction between an ornamental, Canna hybrida ‘Yellow King Humbert,’ and the herbicide simazine. Simazine tolerance levels for C. hybrida were determined by exposing plants for 7 d to 0, 0.01, 0.03, 0.1, 0.3, 1.0, or 3.0 mg‐simazine/L aqueous nutrient media. Response endpoints included fresh mass production after 7 d of exposure and 7 d postexposure and quantum efficiency using dark‐adapted and light‐adapted plants. Simazine uptake and distribution within the plant was determined by exposing plants to 2.02 μCi [14C]simazine in nutrient media (0.242 mg/L) for 1, 3, 5, or 7 d. Plant tissues were combusted and analyzed by liquid scintillation counting. Fresh mass production was reduced 66 and 78% for plants exposed to 1.0 and 3.0 mg/L, respectively. Photosynthetic efficiency measured in dark‐adapted plants was reduced 34 and 60% at the same respective concentrations, whereas photosynthetic efficiency measured in light‐adapted plants was reduced 76 and 92%, respectively. Simazine activity in solution was reduced 80% over 7 d. By day 7, simazine (and/or an impurity) was distributed throughout the plant, but predominantly occurred in the leaves. Uptake of simazine was correlated with water uptake throughout the 7 d. These results suggest that C. hybrida may be a good candidate for incorporation into a phytoremediation scheme for simazine.