Phenols and bud dormancy

Abstract

SUMMARYQualitative analyses of the endogenous phenols of Fagus sylvatica L. were determined separately in leaf primordia and bud scales of dormant buds (apical, subapical and basal) of Fagus sylvatica L. until bud burst.Qualitative analyses in all leaf primordia showed the presence of phenols which are potential cofactors of I.'\A o.xidase (vanillic acid, 2'4,4'-trihydroxychalcone), uncoupling agents of oxidati\'e phospborylation (norwoponin, orobol 7-O-rhamnoglucoside, baicalin, 2'4,4'-trihydr()xychalcone and chlorogenic acid), a synergic stimulator of IAA (cblorogenic acid) and others. In all bud scales the qualitative phenol composition includes a mixture of potential IAA oxidase cofactors (vanillic acid and 2',4,4'-trihydroxychalcone), uncoupling agents (baicalin and 2',4,4'-trihydroxychalcone) and other compounds.In both leaf primordia and bud scales, the qualitative phenol composition does not change significantly during dormancy. These data do not indicate correlations between phenolic matabolism in bud scales and leaf primordia or between single phenolic compounds and the inception and maintenance of dormancy.

Metabolic Changes in Phenolic Compounds in Buds during and after Dormancy Releasing in early and late (<i>Malus sylvestris, </i>Mill) Apple Varieties as Effected by Chilling Requirements

“…81 peach buds. Several studies have shown correlation between bud break and seasonal variation of phenols in trees (Codignola et al, 1988b). The evaluation of dormant buds has shown that, phenol compounds rarely occur in a free state within the cell; rather they are commonly conjugated with other molecules.…”

Cold Hardiness Evaluation of 20 Commercial Table Grape ( vitis Vinifera L.) Cultivars

“…In the present study, the maximum amount of phenolic compounds was observed in Jan. at the same time as the deep winter dormancy, which indicates the association of these compounds with cold tolerance and their protective role in dormant buds of the vine. During the dormant phase, a number of growth inhibitors including phenolic compounds (Caffeic acid, Naringin, Phloridzin, Quercitrin) accumulate in the buds of most trees and after getting enough cold in winter, the concentration of these compounds is minimized at bloom (Codignola et al, 1988). It seems that the precipitate of most phenolic compounds in the canes epidermal and buds scales in the cultivars prevents the development of ice crystals within the internal parts of the bud (Chalker-Scott, 1988).…”