IN-VITRO EFFECT OF FORMALDEHYDE ON DOUGLAS-FIR POLLEN

Formaldehyde (HCHO) concentrations of up to 479 mmol m(-3) have been r eported in urban fogwater, yet little is known about the phytotoxicity of HCHO at such concentrations. We report that formaldehyde at target concentrations of 300, 600, 900 and 1200 mmol m(-3) reduced germinati on of Douglas fir [Pseudotsuga menziesii (Mirbel) France.] pollen irt vitro. Formaldehyde concentrations and pH in media containing pollen d ecreased over 25 h, These effects were not seen with heat-killed polle n nor with media lacking pollen, which may suggest uptake or detoxific ation by live pollen. Stress was indicated by ion leakage from pollen, which increased within 20 h in all HCHO treatments. Reduced pollen vi ability was indicated by TTC staining of pollen, which decreased after HCHO treatment.