Trophic control of bud break in peach (Prunus persica) trees: a possible role of hexoses

Abstract

Vegetative buds of peach (Prunus persica L. Batsch.) trees act as strong sinks and their bud break capacity can be profoundly affected by carbohydrate availability during the rest period (November-February). Analysis of xylem sap revealed seasonal changes in concentrations of sorbitol and hexoses (glucose and fructose). Sorbitol concentrations decreased and hexose concentrations increased with increasing bud break capacity. Sucrose concentration in xylem sap increased significantly but remained low. To clarify their respective roles in the early events of bud break, carbohydrate concentrations and uptake rates, and activities of NAD-dependent sorbitol dehydrogenase (SDH), sorbitol oxidase (SOX) and cell wall invertase (CWI) were determined in meristematic tissues, cushion tissues and stem segments. Only CWI activity increased in meristematic tissues shortly before bud break. In buds displaying high bud break capacity (during January and February), concentrations of sorbitol and sucrose in meristematic tissues were almost unchanged, paralleling their low rates of uptake and utilization by meristematic tissues, and indicating that sorbitol and sucrose play a negligible role in the bud break process. Hexose concentrations in meristematic tissues and glucose imported by meristematic tissues correlated positively with bud break capacity, suggesting that hexoses are involved in the early events of bud break. These findings were confirmed by data for buds that were unable to break because they had been collected from trees deprived of cold. We therefore conclude that hexoses are of greater importance than sorbitol or sucrose in the early events of bud break in peach trees.

Chilling privation during dormancy period and carbohydrate mobilization in Japanese pear trees

“…CWAI activity may be inversely correlated to the sucrose concentration and positively correlated with the glucose and fructose concentrations in the sink tissues (Ito et al, 2002). Maurel et al (2004a) found an increase in CWAI activity in peach buds just before the leafing in natural conditions, but when branches were maintained under chilling privation this activity remained low.…”

Carbohydrate Changes in Peach Shoot Tissues and Their Relationship to Cold Acclimation and Deacclimation

“…Although starch provides a major reserve of carbohydrate in deciduous woody plants and can enhance cold hardiness via hydrolysis to soluble sugars (Morin et al, 2007), starch content in the shoots was not correlated with seasonal changes in cold hardiness in either cultivar (Table 1). Analyses of the composition of xylem sap in peach trees indicate that hexoses (glucose and fructose) are present in addition to sorbitol and sucrose (Maurel et al, 2004a). González-Rossia et al (2008) reported that sorbitol, fructose, and glucose were the main sugars induced in bark tissues by artificial chilling, whereas sucrose was present at the lowest quantities in various Prunus species.…”

Species-specific competition and N fertilization regulate non-structural carbohydrate contents in two Larix species

“…The starch concentration has been found to increase under stressful conditions and decline in favorable environments (Zhang et al, 2008;Duan et al, 2014). C remobilization from a stored C pool has been demonstrated to be an important process during bud burst (Maurel et al, 2004) and root formation (Maillard et al, 2001). Although a part of stored NSC (including starch) was sequestered, the rest, even when blocked for several years, can be remobilized to support recovery from severe disturbances.…”