New Insights into Heartwood and Heartwood Formation

Kampe, Andreas; Magel, Elisabeth

doi:10.1007/978-3-642-36491-4_3

Cited by 62 publications

(51 citation statements)

References 149 publications

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“…However, extractives are accumulated in the cell walls during the heartwood formation. It has been suggested that the extractives were derived from the biosynthesis, oxidation and hydrolysis of precursor substances, which appear as lipophilic apolar droplets during the heartwood formation (Hillis1971; Kampe and Magel 2013;Song et al 2014). Extractives can form coatings on the cell wall and on the pits and can also penetrate the cell wall itself (Hillis and Melbourne 1968).…”

Section: \00044mentioning

confidence: 98%

Comparison of changes in micropores and mesopores in the wood cell walls of sapwood and heartwood

Yin

Song

et al. 2015

Wood Sci Technol

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The objective of this paper was to investigate size distribution of micropores and mesopores within the wood cell walls between sapwood and heartwood by using nitrogen adsorption method and to find out implications for the biological durability and further processing such as in drying and preservation treatment. The pore shape, specific surface area and pore size distribution of Chinese fir (Cunninghamia lanceolata) were evaluated using the hysteresis loops, Brunauer-Emmett-Teller (BET) and density functional theories, respectively. Both the sapwood and heartwood exhibited slit-shaped pores with regard to the H3 type of hysteresis loop of the isotherm. However, more mesopores were found in the sapwood, while the micropores increased with a decrease in mesopores in the heartwood. Furthermore, the earlywood and latewood in the sapwood had a higher BET-specific surface area (2.088 and 1.255 m 2 g -1 , respectively) compared with the earlywood (1.058 m 2 g -1 ) and latewood (0.787 m 2 g -1 ) in the heartwood. This could be caused by an increase in depositions in the extractive that partly filled the mesopores of the heartwood cell walls during the transformation from the sapwood. Additionally, a larger amount of mesopores existed in the earlywood in comparison with the latewood in the sapwood. However, there was no significant difference in the amounts of the micropores and mesopores, when comparing the earlywood with the latewood in the heartwood.

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Section: \00044mentioning

confidence: 98%

Comparison of changes in micropores and mesopores in the wood cell walls of sapwood and heartwood

Yin

Song

et al. 2015

Wood Sci Technol

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“…In 490 addition, transcripts relating both to glycolysis and oxidative pentose phosphate 491 pathway were expressed at an average 2 fold more in TZ than SW, suggesting 492 that the breakdown of sugars is channelled downstream for synthesis of 493 Saranpää and Höll (1989) and Bergstöm (2003) showed that amount of free 501 fatty acids was increased in the TZ and HW but not in SW. In addition, lipophilic 502 droplets were observed in cells of TZ associated with HW formation (Taylor et 503 al., 2002;Kampe and Magel, 2013). Upregulation of phosphoenolpyruvate 504 carboxykinase may indicate that triglycerides are used not only as a direct 505 source of heartwood extractives (free fatty acids), but also as energy and 506 carbon source for stilbenes.…”

Section: Correlation Between Months Of the Year 461mentioning

confidence: 99%

Developmental Changes in Scots Pine Transcriptome during Heartwood Formation

et al. 2016

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Scots pine (Pinus sylvestris L.) wood is desired in woodworking industries due to its favorable timber characteristics and natural durability that is contributed by heartwood extractives. It has been discussed whether the Scots pine heartwood extractives (mainly stilbenes and resin acids) are synthesized in the cells of the transition zone between sapwood and heartwood, or if they are transported from the sapwood. Timing of heartwood formation during the yearly cycle has also not been unambiguously defined. We measured steady-state mRNA levels in Scots pine transition zone and sapwood using RNA sequencing. Year-round expression profiles of selected transcripts were further investigated by quantitative RT-PCR. Differentially accumulating transcripts suggest that, of the Scots pine heartwood extractives, stilbenes are synthesized in situ in the transition zone and gain their carbon-skeletons from Suc and triglycerides. Resin acids, on the other hand, are synthesized early in the spring mainly in the sapwood, meaning that they must be transported to the heartwood transition zone. Heartwood formation is marked by programmed cell death that occurs during the summer months in the transition zone.

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“…The first four steps proceed from several cell layers around the cambium region of a tree stem, whereas HW formation usually occurs a couple of annual rings away from the cambium region. Hence, HW is normally defined as the inner layers of wood without living cells, and the reserve materials (e.g., starch) turn into HW substance in the cells, whereas sapwood (SW) has both living cells and the reserve materials [2,3]. In between the SW and HW, the transition zone (TZ) is located.…”

Section: Introductionmentioning

confidence: 99%

“…This process normally produces inner darker-colored HW, often easily recognizable from the paler outer SW. These extractives often render HW its natural durability, esthetic characteristics, pharmaceutical applications, and commercial value [3].…”

Section: Introductionmentioning

confidence: 99%

“…HW formation is described as a form of programmed cell death [15], and it has been suggested that the longevity of the ray parenchyma cells and the depletion of reserve materials are closely related to the HW formation process [3,16]. Previous research has shown that the ray parenchyma cells of Taiwania gradually lose the starch grains from the inner SW and lose their nuclei in TZ, whereas the colored substances deposit into the cell lumens in the TZ [17].…”

Section: Introductionmentioning

confidence: 99%

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Differential Gene Profiling of the Heartwood Formation Process in Taiwania cryptomerioides Hayata Xylem Tissues

Yeh

Chu

Liu

et al. 2020

IJMS

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Taiwania (Taiwania cryptomerioides) is an important tree species in Taiwan because of the excellent properties of its wood and fascinating color qualities of its heartwood (HW), as well as the bioactive compounds therein. However, limited information is available as to the HW formation of this species. The objective of this research is to analyze the differentially expressed genes (DEGs) during the HW formation process from specific Taiwania xylem tissues, and to obtain genes that might be closely associated with this process. The results indicated that our analyses have captured DEGs representative to the HW formation process of Taiwania. DEGs related to the terpenoid biosynthesis pathway were all up-regulated in the transition zone (TZ) to support the biosynthesis and accumulation of terpenoids. Many DEGs related to lignin biosynthesis, and two DEGs related to pinoresinol reductase (PrR)/pinoresinol lariciresinol reductase (PLR), were up-regulated in TZ. These DEGs together are likely involved in providing the precursors for the subsequent lignan biosynthesis. Several transcription factor-, nuclease-, and protease-encoding DEGs were also highly expressed in TZ, and these DEGs might be involved in the regulation of secondary metabolite biosynthesis and the autolysis of the cellular components of ray parenchyma cells in TZ. These results provide further insights into the process of HW formation in Taiwania.

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New Insights into Heartwood and Heartwood Formation

Cited by 62 publications

References 149 publications

Comparison of changes in micropores and mesopores in the wood cell walls of sapwood and heartwood

Comparison of changes in micropores and mesopores in the wood cell walls of sapwood and heartwood

Developmental Changes in Scots Pine Transcriptome during Heartwood Formation

Differential Gene Profiling of the Heartwood Formation Process in Taiwania cryptomerioides Hayata Xylem Tissues

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