Absorption of atmospheric C 2–C 5 aldehydes by various tree species and their tolerance to C 2–C 5 aldehydes

Abstract

To estimate the effect of tree planting on atmospheric C 2–C 5 aldehydes, a study was made on the absorption of, and tolerance to, C 2–C 5 aldehydes by various tree species. The absorption rates ranged from 10.2 for acetaldehyde (Japanese black pine) to 107 ng dm −2 h −1 ppb −1 for n-valeraldehyde (locust) at 1000 μmol of photons m −2 s −1. The absorption rates of C 2–C 5 aldehydes increased in the following order: coniferous tree species <evergreen broad-leaved tree species <deciduous broad-leaved tree species; trees exhibiting higher absorption rates of C 2–C 5 aldehydes had greater transpiration rates. In experiments with three species in which the light intensity was varied, there was a linear relationship between the absorption rate of a particular C 2–C 5 aldehyde and the transpiration rate. In comparison with the absorption rates estimated from a simplified gas diffusive resistance model, we conclude that C 2–C 5 aldehydes are absorbed through the stomata and are metabolized fairly rapidly within the leaf tissue, although the absorption rates are slightly less than the estimated potential absorption rates. At total C 2–C 5 aldehyde concentrations of less than approximately 3000 ppb, two orders of magnitude larger than the actual indoor or outdoor concentrations, evergreen broad-leaved tree species and coniferous tree species have the ability to absorb atmospheric C 2–C 5 aldehydes for at least 8 h without any visible foliar injury. Although deciduous broad-leaved tree species have lower tolerance to gaseous C 2–C 5 aldehydes than evergreen broad-leaved and coniferous ones, they have enough ability to absorb atmospheric C 2–C 5 aldehydes at total concentrations of approximately 400 ppb without visible foliar injury. We conclude that trees in general could act as an important sink for atmospheric C 2–C 5 aldehydes.