Neutral lipids and phospholipids in Scots pine (Pinus sylvestris) sapwood and heartwood

Abstract

Variations in the concentration and composition of triacylglycerols, free fatty acids and phospholipids were analyzed in Scots pine (Pinus sylvestris L.) trees at five sites. Disks were taken at breast height or at a height of 4 m from the stems of 81 trees differing in diameter and growth rate. The mean concentration of triacylglycerols in sapwood was 26 mg g(-1) dry mass; however, variation among trees was large (16-51 mg g(dm)(-1)). The concentration of triacylglycerols was slightly larger at 4 m height in the stem than at breast height. Concentrations of triacylglycerols did not differ between the sapwood of young and small-diameter stems (DBH < 12 cm) and the sapwood of old stems (DBH > 36 cm). Concentrations of free fatty acids were negligible in the outer sapwood, but ranged between 5 and 18 mg g(dm)(-1) in the heartwood. The most abundant fatty acids of triacylglycerols were oleic (18:1), linoleic (18:2omega6, 18:2Delta5,9), linolenic (pinolenic, 18:3Delta5,9,12 and 18:3omega3) and eicosatrienoic acid (20:3Delta5,11,14 and 20:3omega6). The concentration of linoleic acid comprised 39-46% of the triacylglycerol fatty acids and the concentration was higher in the slow-growing stem from northern Finland than in the stems from southern Finland. Major phospholipids were detected only in sapwood, and only traces of lipid phosphorus were detected in heartwood.

Analysis on Storage Off-Gas Emissions from Woody, Herbaceous, and Torrefied Biomass

“…The storage temperature acts as a catalyst to accelerate the chemical oxidation process. Research studies conducted by Back and Allen [14], Höll and Pieczonka [15], and Piispanen and Saranpä ä [16] on woody biomass (Scots pine and Norway spruce) indicated that triglycerides undergo auto-oxidation in the presence of temperature and emit off-gases like CO and hexanal. Springer and Hajny [34], Kuber et al [35], and Kuber [36,37] have established that auto-oxidation of unsaturated fatty acids and other extractives leads to spontaneous heating of wood chips and sawdust during storage.…”

“…These reported CO and CO2 emissions for wood chips and wood pellets are well above the threshold concentration levels established by U.S. Department of Labor Occupational Safety and Health Administration. According to Back and Allen [14], Höll and Pieczonka [15], and Piispanen and Saranpä ä [16], dry woods like Scots pine and Norway spruce contain about 3%-5% triglycerides, which can undergo oxidation and yield hexanal and other off-gases (such as CO). Svedberg et al [11] indicated that in addition to CO, wood pellets also emitted hexanal during storage.…”

The carbon charging of pines at the climatic treeline: a global comparison

“…5). Saranpää and Nyberg (1987) Piispanen and Saranpää (2002) reported lipid concentrations in the outer stem sapwood (first 1-2 cm) for P. sylvestris from southern Finland to vary from tree to tree from 1.6 to 5.1% d.m. (mean ca.…”

Extractives of mechanically wounded wood and knots in beech

“…The content of stearic acid was comparable in rZ and K. The total content of identified free fatty acids in rZ and K is 1.8-2.5 times higher than in sW (Figure 3). In heartwood (hW) forming species, like pines and black locust, the concentration of free fatty acids is the highest in the hW (Hillinger et al 1996;Piispanen and Saranpää 2002). Similarly to the process of hW formation (Hillinger et al 1996), free fatty acids in the rZ of beech could originate from the hydrolysis of sapwood triacylglycerols.…”