Distribution of endogenous indole-3-acetic acid and compression wood formation in reoriented branches of Douglas-fir

• Published in: Plant physiology (Bethesda) Vol. 91; no. 1; pp. 338 - 344
• Main Authors: Wilson, B.F. (University of Massachusetts, Amherst, MA), Chien, C.T, Zaerr, J.B
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.09.1989
• Subjects: ACIDE INDOLACETIQUE; ACIDO INDOLACETICO; ANALISIS; ANALYSE; Auxins; Biological and medical sciences; BOIS DE REACTION; Branches; Cell walls; Compression wood; DIFERENCIACION; DIFFERENCIATION; Fundamental and applied biological sciences. Psychology; MADERA DE REACCION; Physical agents; Pine trees; Plant physiology and development; Plants; PSEUDOTSUGA MENZIESII; RAMIFICACION; RAMIFICATION; Stems; Surface areas; Tracheids; Vegetative apparatus, growth and morphogenesis. Senescence; XILEMA; Xylem; XYLEME; Plant tissue; Growth; Pseudotsuga menziesii; Mechanical factor; Phloem; Growth stress; Branch; Indoleacetic acid; Gymnospermae; Xylene; Reaction wood; Plant growth substance; Coniferales; Spermatophyta; Cambium
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.91.1.338

Five-year-old segments of intact 7-year-old branches of Douglas-fir (Pseudotsuga meziesii [Mirb.] Franco) were reoriented to determine the relations between indole-3-acetic acid (IAA) and the formation of compression wood. Eight branches per treatment were either left at their original angle (mean of 69 degrees, the control), or bent proximal to the segment to reorient it up or down 30 degrees. Differentiating xylem tissue from the upper and lower sides of each segment was collected and extracted separately for IAA analysis by in-line fluorescence detection of free IAA and IAA methyl ester after sequential C18 reversed-phase high performance liquid chromatography. The IAA methyl ester was confirmed by gas chromatography-mass spectroscopy. Compression wood formed on the upper side of branches reoriented up and on the lower side of controls or branches reoriented down. IAA was present in all samples. The difference in IAA concentration between upper and lower sides was either not correlated, or negatively correlated in segments reoriented down, with both the occurrence of compression wood and the rate of new tracheid production. Mean concentrations for whole branch segments were not affected by the treatments regardless, of whether IAA concentrations were expressed on a surface area, weight, or cell basis