Efficiency and mechanism of formaldehyde removal from air by two wild plants; Plantago asiatica L. and Taraxacum mongolicum Hand.-Mazz.

Abstract

Indoor potted plants played an important role in the removal of air-borne VOCs. According to the difference between plant fresh extracts and boiled extracts on breakdown ability to the added formaldehyde, a simple quantitative evaluation method was used to identify the mechanisms of formaldehyde removal from the air by wild Taraxacum mongolicum Hand.-Mazz. and Plantago asiatica L.. After shoots exposure to formaldehyde (1.28mg/m3 in the air) for 24h, the formaldehyde removal rates of P. asiatica and T. mongolicum were 73.18 and 121.20mg/h/kg FW (fresh weight), respectively. Formaldehyde can be transported from the air to the rhizosphere solution by plants, and the maximum rates of transmission by T. mongolicum and P. asiatica were 23.73 and 83.08mg/h/kg FW, respectively. Although plant metabolism was responsible for formaldehyde loss in the air-plant-solution system, and the metabolic activity depended on the enzymatic and redox reactions in the plants, P. asiatica and T. mongolicum are still good candidate species for developing phyto-microbial technologies. The redox reaction was the main mechanism used by P. asiatica shoots to dissipate formaldehyde, while the enzymatic reaction was the main mechanism used by T. mongolicum. The higher oxidative potential and lower defensive enzyme activity in P. asiatica shoots led to its higher formaldehyde removal rate compared to T. mongolicum. Meanwhile, the stronger redox reaction ability in the T. mongolicum roots was partly responsible for its lower formaldehyde transmission rate. The results show two plants have strong tolerance to formaldehyde in the air and good formaldehyde removal ability.