STATISTICAL ANALYSIS TO DETERMINE THE RELATIVE IMPORTANCE OF VARIABLES INVOLVED IN FOLIAR TRANSLOCATION
A recent study used a novel relationship to establish the relative importance of species, active ingredient (AI), AI concentration (g L -1 ), and surfactant to foliar uptake. The relationship used was nmol mm -2 uptake versus initial dose (ID; nmol mm -2 applied) and was termed the uptake ratio. The current study used a similar relationship (nmol mm -2 translocation versus ID; termed the translocation ratio) to establish the relative importance of the same variables to foliar translocation. Species, AI, its concentration, and surfactant all significantly affected the translocation ratio (explaining 33% of the deviance). However, AI concentration played only a minor role (p = 0.0011; 2% deviance). The percentage deviance explained by each of the other primary variables was 6% (surfactant), 8% (AI), and 18% (species). The most important interaction was between AI and species, which explained 13% of the deviance, followed by AI and surfactant explaining 9% of the deviance, and surfactant and species explaining 8% of the deviance. Overall, 82% of the deviance could be explained. More useful was the analysis of the individual xenobiotics, where the models explained 79%, 84%, and 74% of the variance in the translocation ratio for 2-deoxy-D-glucose (DOG), 2,4-D, and epoxiconaxole, respectively. In the case of 2,4-D, species, surfactant, and AI concentration all significantly affected the translocation ratio. However, for DOG, only species and surfactant were significant, and for epoxiconazole only species significantly affected the translocation ratio. The effect of surfactant on translocation decreased with increasing AI lipophilicity, with surfactant having no significant effect on the translocation of epoxiconazole.