Quantification of juvenile hormone III in the sedge Cyperus iria L.: Comparison of HPLC and radioimmunoassay

Juvenile hormone III (JH III), a sesquiterpenoid involved in the regulation of insect development and reproduction, appears to be ubiquitous in insect s and has also been isolated from some species of sedge. The quantification of JH III extracted from the sedge Cyperus iria by HPLC and by radioimmuno assay (RIA) has been compared. The RIA, developed originally to determine i nsect haemolymph titres, was optimized for the analysis of plant tissues. T he antiserum 31867 displayed minimal cross-reactivity with precursors of JH III from the insect biosynthetic pathway or with extracts from related pla nt species. Analysis of standards and plant extracts by HPLC and RIA confir med that there was no significant difference between the ability of these t wo techniques to quantify JH III (paired t-test), Therefore, RIA was subseq uently used to determine the distribution of JH III in mature plants of C. iria, Substantial concentrations were detected in the above-ground plant ti ssues (0.2-1.2 mu g/g fresh weight), but the majority of JH III was found i n the roots (43.5 mu g/g fresh weight). Copyright (C) 2000 John Wiley & Son s, Ltd.