Abstract:
Definitive evidence for the occurrence and seasonal variation of indole-3 -acetic acid (IAA) in shoots 0 DougLas-fir (Pseudotsuga rrienztesii (Mirb. ) Franco) was sought. Collections obtained in December and June were extracted by solvent using methanol arid diethyl ether arid by certtrtfugatiori. Extraction by ceritrifugation appeared to be twice as effective as solvent extraction with diethyl ether in removing IAA from shoot material. Qualitative and quantitative information was acquired by gas-liquid chromatographic separation of methyl and/or trimethyls ilyl derivatives
of plant extract components. Results from three columns containing physically different stationary phases support the contention that IAA does occur in Douglas-fir and its levels vary seasonally. Mass analysis of a synthetic IAA peak and the proposed endogenous LAA peak from two representative extracts gave definitive support to gas-liquid chromatography data and established the presence of JAA in Douglas -fir.
