Endogenous abscisic acid levels in stems and axillary buds of intact or decapitated broad‐bean plants (Vicia faba L.)

Abstract

Endogenous levels of abscisic acid (ABA) were measured by gas‐liquid chromatography (electron capture) in stems and axillary buds of intact or decapitated broad‐bean plants (Vicia faba L. cv. Aguadulce). Endogenous ABA was distributed in the main axis according to a concentration gradient from the apical part of the stem towards the base. Axillary buds contained ABA levels which were from 4 to 9 times higher than those in the corresponding nodes and internodes. Decapitation of the plant was followed within 6 h by a large decrease of ABA levels in all the parts of the main axis. The diminution of ABA content was the most important in axillary buds released from apical dominance. Twenty‐four hours after the decapitation, the ABA concentration further decreased in the upper parts of the stem, while no modification was observed in the basal parts of the stem containing the smallest levels of ABA.

Light Regulation of Axillary Bud Outgrowth Along Plant Axes: An Overview of the Roles of Sugars and Hormones

“…The role of ABA as an inhibitor of bud outgrowth was long hypothesized based on the observations that exogenous ABA supply inhibits bud outgrowth (White and Mansfield, 1977; Chatfield et al, 2000; Cline and Oh, 2006; Corot et al, 2017; Yuan et al, 2018) and that the bud ABA content is negatively correlated to the bud ability to grow out. In particular, the bud ABA level decreases in response to decapitation and increases in response to exogenous auxin supply in annual plants (Eliasson, 1975; Everatbourbouloux and Charnay, 1982; Knox and Wareing, 1984; Gocal et al, 1991), and ABA accumulates during cold-induced bud dormancy in perennial plants (Rohde et al, 1999; Arora et al, 2003; Wang et al, 2016a). Mutants recently confirmed a role of ABA in bud outgrowth regulation.…”

Indolamine accumulation and TDC/T5H expression profiles reveal the complex and dynamic regulation of serotonin biosynthesis in tomato (Solanum lycopersicum L.)

“…Interestingly, although tryptamine levels were constant along the stem, we observed a gradient of serotonin with opposite polarity to the gradient in leaves. Concentration gradients in the stem have already been reported for phytohormones including auxin ( Kojima et al, 2002 ), abscisic acid ( Everat-Bourbouloux and Charnay, 1982 ) and cytokinins ( Eklöf et al, 1996 ), yet at much lower levels than serotonin (10–0.1 ng g −1 FW).…”

Concomitant analysis of cambial abscisic acid and cambial growth activity in poplar

“…Interestingly, Pharis et al (1981) who used a similar approach also reported a growth promotion of xylem cells in ABA-treated seedlings of Radiata pine. Further, circumstantial evidence supporting a positive correlation between cambial region ABA and cambial growth activity comes from observations showing that ABA in non-stressed plants is mainly synthesized in green shoots and leaves and then transported via phloem and xylem towards different plant organs (Eliasson 1975;Everat-Bourbouloux and Charnay 1982;Lachaud 1989;Wolf et al 1990). Assuming shoots and leaves are also the main source for cambial region ABA, a change of hormone synthesis in these plant organs would have a strong influence on the level of ABA in the cambial zone.…”