A Specific Radioimmunoassay for the Determination of Low Quantities of Indole-3-acetic Acid in Spruce Needles of Healthy and Damaged Trees

Summary The aim of the present investigation was to develop a radioimmunoassay for the quantification of indole-3-acetic acid in needles of Picea abies in damaged and phenotypically healthy trees. Phenols, lipophilic substances or compounds with cross-reactivity had to be separated from the extracts in several purification steps. Measurements were carried out between May and October 1986 on trees from two spruce plantations. Marked differences were found in IAA content in needles of healthy and damaged trees. In most cases the needles of the damaged trees contain lower endogenous IAA levels. The auxin levels also depended on the age of the tree, the year of needle formation, and the vegetat…