Uptake of some volatile alkyl methylphosphonofluoridates from the vapour phase by wheat plants

The uptake of cyclohexyl, isopropyl and 1,2,2‐trimethylpropyl methylphosphonofluoridates from the vapour phase by growing wheat plants was studied. The compounds were absorbed through the leaves of the plants and were degraded in a manner similar to that following their uptake through the roots from hydroponic culture solution. The levels of the methylphosphonic acid derivatives in the plant extracts were influenced by the vapour concentration of the methylphosphonofluoridate, the period of exposure to the vapour and the state of illumination of the plants, but were not markedly influenced by the chemical nature of the compounds. Likely mechanisms for the uptake are discussed and it is concluded that the main route of absorption involves the stomata. The studies suggest that growing plants can absorb and possibly have a “sink effect” for atmospheric organophosphorus contamination.