On the Question of Occurrence of Indole-3-Acetic Acid in Pinus silvestris

Abstract

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The radial distribution and metabolism of IAA-14C in Pinus echinata stems in relation to wood formation

“…In the present study the seasonal change in the extent of IAA distribution in the maturing xylem coincided with the microscopically observed transition to latewood formation in the stems. As previously found for other species of conifers (Wodzicki and Peda 1963 ;Whitmore and Zahner 1966;Wodzicki 1971;Skene 1972), an increased width of the maturation zone of the stems was observed microscopically in late season with the advent of latewood formation, i.e. the maturation zone increased from 4-5 cells in May (150-190j~m) to 8-10 cells in August (200-300 jLrn).…”

“…under vacuum at 35"C, acidified with 0.1 N HC1, and partitioned (3 X) with peroxide-free ethyl ether as described by Wodzicki (1968). Before ether partitioning, the total radioactivity recovered was determined by pipetting aliquots of the reduced MeOH extract onto small rectangles of silica gel G layer, scraping the dried gel into vials, and measuring radioactivity by scintillation counting as described for sections.…”

“…The physiological mechanisms causing this seasonal transition from earlywood to latewood formation have been rather intensively investigated, but are still poorly understood (Wareing 1958;Larson 1962;Balatinecz and Kennedy 1968;Gordon and Larson 1968;Whitmore and Zahner 1966;see relevant papers in Zimmer~nann 1964). Recent findings indicate that in some conifers the increased tracheid wall thickness accompanying latewood formation results from an increase in the duration of the period of secondary wall deposition (Wodzicki 1971;Denne and Smith 197 1 ;Skene 1972). It is during secondary wall deposition or the maturation stage3 of tracheid differentiation that the bulk of usable wood substance is produced.…”

On the identification of native auxins in citrus tissues

“…(14,16,17). In their discussion of the Coleus case, Scott and Jacobs (14) emphasized the biochromatographic results, bringing forth the difficulties in obtaining reliable results with the chromogenic and fluorometric methods, probably because of the interference of other plant constituents (18). It seems that the bioassay techniques remain the most sensitive and most specific methods for the detection of minute amounts of plant hormones in relatively crude plant extracts.…”

Occurrence of Indole‐3‐Acetic Acid in Buds of Pinus silvestris

“…Recently Wodzicki (1968) reported on extensive work on an auxin found in extracts of the inner bark of Pinus silvestris. This substance behaved as IAA when chromatographed in several solvent systems, gave positive response in the Avena mesocotyl test, the Avena coleoptile ctu'vature test and the wheat coleoptile straight-growth test, but showed no activity in a gibberellin test.…”