Relationship between hydrophobicity parameters and the strength and selectivity of phytotoxicity of sulfosuccinic acid esters

The strength and selectivity of the phytotoxicity of 11 sulfosuccinic acid ester surfactants were determined on the leaves of Tradescantia bicolor, and the data were evaluated by multivariate mathematical-statistical methods. Spectral mapping technique combined with stepwise regression analysis indicated that both the strength and the selectivity of the effect depend significantly on the specific hydrophobic surface area of the anionic surfactants determined in the presence of ions. The significant relationship between this hydrophobicity parameter and phytotoxic activity suggests the involvement of apolar (hydrophobic) forces in the plant - surfactant interaction. It was assumed that the apolar alkyl chains of the surfactants may insert in the hydrophobic part of the phospholipid bilayers causing membrane disorder and malfunction.