Food reserves of scots pine (Pinus sylvestris L.)

Abstract

Starch, soluble sugars, triacylglycerols, diacylglycerols and free fatty acids were measured in 30-year-old Scots pine (Pinus sylvestris L.) trees during an annual cycle in the sapwood (youngest ten xylem rings). The radial distribution of carbohydrates and lipids was studied in the trunkwood of 90-to 150-year-old Scots pine trees collected at the end of the growing season. Determination of the compounds was performed using specific enzymatic assays, capillary gas chromatography and thin layer chromatography. The amounts of glucose, fructose, sucrose, and galactose/arabinose in the sapwood were slightly higher in winter than in summer. Raffinose/stachyose increased up to 5-fold during the cold period. At the beginning of the growing season starch amounts rose, and then decreased in summer and autumn. No concentration changes were observed in the total amounts of diacylglycerols and fatty acids throughout the year. Triacylglycerol levels were slightly higher in February than in summer and autumn. Relative frequencies of individual fatty acids were similar in all lipid fractions. Glucose, fructose, sucrose, starch and triacylglycerols disappeared almost entirely at the transition zone from sapwood to heartwood. In contrast, free fatty acids and galactose/arabinose rose in centripetal direction, and diacylglycerols remained constant across trunk cross-sections. The relative amounts of individual fatty acids changed markedly in the free fatty acid fraction and in the triacylglycerols when crossing the sapwoodheartwood boundary. Concentration changes of reserve materials are discussed in relation to season, mobilization and translocation processes, dormancy, frost resistance, and heartwood formation. The results are compared to those found in needles.

Nonstructural Carbon in Woody Plants

“…Similar seasonal trends have been observed in drought-deciduous trees in semiarid climates, where stemwood NSC concentrations decrease during leaf expansion and reproduction and are higher during the dry season than during the wet season (92,149). In evergreen conifers, NSC declines sharply from the sapwood to hardwood, concentrations of sugars are higher during winter than during summer, and starch peaks at the beginning of the growing season (34,128). In deciduous conifers, seasonal variations are smaller and similar to those in diffuse-porous trees (48).…”

Differential and interactive effects of temperature and photoperiod on budburst and carbon reserves in two co‐occurring Mediterranean oaks

“…2000), while lipids may supply carbon skeletons and energy for shoot elongation (Jordy 2004). In contrast, other authors have observed a reduction in starch from leaves and roots during spring (Fischer & Höll 1991; Egger et al. 1996; Cerasoli et al.…”

Dynamics of non‐structural carbohydrates in terrestrial plants: a global synthesis

“…This view is supported by several studies showing that starch is more depleted than SS under lethal drought (Adams et al 2013, Mitchell et al 2013, Sevanto et al 2014, Dickman et al 2015, Garcia-Forner et al 2016, and by modeling and empirical results indicating that NSC has two distinct pools with different turnover times (Richardson et al 2013(Richardson et al , 2015. Mutual conversion between starch and sugars commonly results in relative stable NSC levels, compared to larger seasonal oscillations of starch and SS (Fischer and Höll 1991, Terziev et al 1997, Richardson et al 2013Figs. 1), which involves highly regulated biochemical pathways (Dietze et al 2014).…”