Submitted to: International Symposium on Adjuvants for Agrochemicals
Publication Type: Abstract only
Publication Acceptance Date: 7/1/1998
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Epicuticular wax is the outermost barrier to, and determinant of reaction to, pesticide spray deposition, spread, and penetration on leaf surfaces. Wax components on leaf surfaces vary among species and are thought to be instrumental in affecting the structural and functional aspects of leaf epicuticular wax. We have previously reported on the composition of Johnsongrass leaf epicuticular wax. In this abstract we are reporting on the composition of epicuticular wax from soybean leaves with differing levels of pubescence (isolines of dense, normal and glabrous). Epicuticular wax was extracted with chloroform, filtered, dried in vacuo, weighed, and silanized for GC/MS analysis. The samples were examined as the whole wax using a procedure developed in our laboratory. Wax component identification is possible for most of the resultant peaks, using GC retention times and mass spectral patterns. The epicuticular wax, as determined by our system, consists of a mixture of simple aliphatic hydrocarbons (C21-C35), primary alcohols (C16-C32), secondary alcohols (C23 and C24), and carboxylic acids (C14-C36). The presence of higher molecular weight fractions were not observed due to the 650 dalton limit of our mass analyzer. The pubescence factor had little effect on wax composition. Once the components of soybean leaf epicuticular wax are determined, a model system can be constructed to aid in design of appropriate spray adjuvants and pesticide formulations.