A rapid method to assess the formaldehyde dehydrogenase activity in plants for the remediation of formaldehyde

The formaldehyde dehydrogenase (FADH) activity in plants is essential to the removal of airborne formaldehyde (FA) by plants. A rapid and efficient method was established to assess the FADH activity in plants by analyzing the efficiencies of the extracts of fresh and enzyme-inactivated leaves to degrade FA, with the enzyme-inactivated leaves prepared by freezing with liquid nitrogen. The efficiencies of airborne FA dissipated by different plants were evaluated through the FA fumigation experiments using four selected plants, with the results analyzed against the calculated leaf FADH activities. Fresh and enzyme-inactivated leaf extracts degraded FA to different extents. The degradative efficiencies of leaf extracts were positively related to the initial FA test levels at 6-18 mg l^-1. The relative plant-leaf FADH activities formed the order of Chenopodium album L. > Atenia cordifolia > Plantain > Aloe, which was in line with the observed FA dissipating efficiencies of the plants exposed to 0.72 mg m^-3 airborne FA for 24 h. Other dominant degrading mechanisms in plant leaves resulted in higher dissipating efficiencies of Plantain over that of Atenia cordifolia when exposed to 1.56 mg m^-3 FA for 24 h. The established method could be applied to estimate the FADH activity in plants for assessment of the plant remediation efficiency of FA in air at lower concentrations.