Subcellular distribution governing accumulation and translocation of pesticides in wheat (Triticum aestivum L.)

Root uptake, translocation, and subcellular distribution of six pesticides (dinotefuran, thiamethoxam, imidacloprid, imazethapyr, propiconazole, and chlorpyrifos) with K-ow ranging from -0.549 to 4.7 were investigated in wheat to study transportation and accumulation of pesticides. The root bioconcentration factor (RCF) of pesticides decreased with water solubility (R-2 = 0.6121) and increased with hydrophobicity (when the pH-adjusted log K-ow > 2, R-2 = 0.925), respectively. The translocation of neutral pesticides from roots to shoots increased positively with water solubility (R-2 > 0.6484) but decreased with hydrophobicity (R-2 > 0.8039). The subcellular fraction concentration factor (SFCF) increased linearly with hydrophobicity of the tested pesticides (R-2 > 0.958). The log RCF was positively correlated with log SFCF in root cell walls (R-2 = 0.9894) and organelles (R-2 = 0.9786). Transportation of the pesticides from roots to stems and stems to leaves was adversely affected by the log SFCF of cell walls and organelles of roots (R-2 > 0.7997) and stems (R-2 > 0.6666), respectively. Hydrophobicity-dependent SFCF is a factor governing accumulation of pesticides in roots after uptake and their subsequent upward translocation. (C) 2020 Elsevier Ltd. All rights reserved.