Abscisic acid, abscisic acid-esters and phaseic acid in vegetative terminal buds of Acer pseudoplatanus during emergence from winter dormancy

Abstract

Levels of free-abscisic acid and "boundabscisic acid" (alkaline hydrolyzable abscisic acidesters) in replicated samples of terminal vegetative buds of sycamore trees were measured during natural emergence from winter dormancy by gas chromatographic methods together with isotope dilution estimation of recovery rates. Not until after the buds had been released from true dormancy in January by winter chilling did any clear change occur in either abscisic acid (ABA) fraction, or in total ABA, on any basis of comparison. The percentage of total ABA present as the free acid declined at the end of true dormancy to approximately two-thirds of its value in the earlier winter months. It is concluded that glucosylation of ABA is unlikely to play a major part in the mechanism of release from dormancy in vegetative sycamore buds. At the end of true dormancy there was a large transient increase in what appeared to be phaseic acid, but this was not accompanied by any marked decrease in either free- or bound-ABA.

Effect of thidiazuron on abscisic acid content in apple bud relative to dormancy

“…Based on the above information, the compound from apple bud extracts was concluded to be ABA, ABA content in apple buds Thidiazuron stimulated bud break at 25 ^^f, but untreated buds from the same plants and buds from control plants remained dormant as previously reported (Wang et al, 1986), Two weeks after treatment with thidiazuron, the amount of ABA in treated buds was calculated to be 15,0, 14,6 and 12,7 nmol (g dry weight)"' by ELISA, GC, and lettuce hypocotyi bioassay, respectively, A good correlatioti was found between results obtained from ELISA and GC, A similar correlation between these two methods was reported by Leroux et al, (1985), Thidiazuron induced bud break and bud development. At the time of bud break induced by thidiazuron, the treated bud contained a comparable level of ABA as the control bud, which remained dormant (Fig, 1), In this respect, ABA did not particularly seem to regulate dormancy, Phillips and Hofmann (1979) reported that levels of free, bound or total ABA in vegetative terminal buds of Acer pseudoplatanus did not change until after the buds were released from true dormancy, indicating that ABA contents were not correiated to the emergence of buds from dormancy, Swartz and Powell (1981) also showed that the peak of ABA level in the bud of late bloomers was about 3 weeks before bud break. In addition, ABA levels did not correlate with the time of bud break nor with the date of bloom in early or late blooming cultivars.…”

8. The role of plant growth regulators in dormancy in forest trees

“…pubescens and Wright's (105) on Fagus sylvatica Phillips and Hoffman (80) found that for B . Also using GLC with isotope dilution, Phillips and Hoffman (80) examined the levels of "free" and "bound" ABA in buds of A .…”

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

“…2D). This property is often used to identify ABA in plant extracts (Lenton et al 1971, Chamay and Bongen-Ottoko 1977, Phillips and Hofmann 1979.…”