Testing Nerium oleander as a biomonitor for surfactant polluted marine aerosol.

Oleander was tested as biomonitoring plant for surfactant polluted marine aerosol. Potted plants in the greenhouse were sprayed once a week for 5 weeks with seawater containing sodium dioctyl sulfosuccinate (SDS) at the following concentrations: 5, 10, 15, 30, 60, 120, 250, 500 mg/L. A significant correlation was found between SDS concentration in the spray and surfactant deposit on the leaves at the end of the 5 weeks. At that time and two months later, we assessed: leaf visible injury, foliar chloride content, damage to stomatal crypts, water potential, net photosynthesis and stomatal conductance. Relative to controls (not sprayed and sprayed either with deionized water or with seawater without surfactants), all the parameters were affected (P<0.05) by the presence of surfactant. Furthermore they were correlated (P<0.05) with the concentration of surfactant. Visible injury occurred after treatments containing concentrations of surfactant exceeding 30 mg/L