Modeling plant uptake of airborne organic chemicals. 1. Plant cuticle/water partitioning and molecular connectivity

Abstract

Molecular connectivity indexes were tested with regard to their ability to describe the cuticle/water partitioning for a variety of organic chemicals. A model is derived that accounts for 99% of the variation in the published cuticle/water partition coefficients (Kcv¡), which cover the range of 8.5 orders of magnitude. It is shown that the molecular size is directly proportional to the cuticle/water partition coefficients. It is also the most important structural feature that accounts for 89% of the variation in the measured Kcv/ data. Moreover, the molecular connectivity model outperforms in accuracy and speed the traditional empirical models based on 1-octanol/water partition coefficients or water solubilities. Our results and their comparison with previously published models demonstrate that the molecular connectivity model is an accurate predictive tool for the cuticle/water partition coefficients of a wide range of commercial chemicals and that it can be confidently used to assess their potential to penetrate and to accumulate in aboveground vegetation.

Can ornamental potted plants remove volatile organic compounds from indoor air? — a review

“…Indeed, in work with modelling plant uptake of xenobiotics the VOC characteristics that are included are often the 1-octanol/water partition coefficient and the Henry's law constant or the air/water partition coefficient (Bacci et al 1990;Riederer 1995;Trapp 2007). The ease of entry through the cuticle has been shown to be directly proportional to the molecular size of the compound (Sabljic et al 1990). These investigations are conducted within an agricultural or outdoor bioremediation context with pollutants such as pesticides or PAHs, and much is based on theoretical calculations.…”

“…The relationship between removal and VOC identity may be further explored by looking at parameters such as molecular size, 1-octanol/water coefficient and Henry's law constant (Bacci et al 1990;Riederer 1990;Sabljic et al 1990;Trapp and Matthies 1995). Uptake of pollutants has earlier been noted to be independent of functional group or molecular weight (Bromilow and Chamberlain 1995), but for degradation studies, functional groups may be a relevant factor (Korte et al 2000).…”

Role of needle surface waxes in dynamic exchange of mono- and sesquiterpenes

“…In addition to gas-phase reactions, heterogeneous reactions are known to play a key role in BVOC chemistry (Shen et al, 2013). It has been suggested that some of the BVOCs produced by foliage could be attached to the epicuticular waxes (Sabljic et al, 1990;Welke et al, 1998), providing additional protection against oxidants, but scientific knowledge on this issue is currently very limited. At least in theory BVOCs also affect the formation of water films on leaf surfaces (Rudich et al, 2000;Sumner et al, 2004), thereby enhancing O 3 deposition mediated by surface wetness.…”

Uptake of chlorobenzenes by tissues of the soybean plant: Equilibria and kinetics

“…In both approaches it is lipid, wax, or cutin phases that apparently absorb most of the chemical and are thus of primary interest when evaluating and correlating partitioning. The significance of lipids, waxes, and cutin as sites of absorption and accumulation of organic chemicals has been discussed and studied by numerous authors including Kirkwood [8], Sabljic and Güsten [9], Kerler and Schönherr [10], Schö nherr el al. [11], and Reischl et al [12].…”