Histochemistry of reaction wood differentiation in Pinus radiata D. Don

1967 ◽  
Vol 15 (3) ◽  
pp. 377 ◽  
Author(s):  
G Scurfield

Histochemical tests have been applied to a study of the differentiation of the cell walls in reaction wood (compression wood) formed in the stems of horizontally grown seedlings of Pinus radiata. The results are discussed on the basis of the chemical specificity of the tests and the information they provide as to the chemical changes which occur in the cell walls.

IAWA Journal ◽  
2006 ◽  
Vol 27 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Linda C.Y. Hsu ◽  
John C.F. Walker ◽  
Brian G. Butterfield ◽  
Sandra L. Jackson

We investigated the potential for the roots of Pinus radiata D. Don to form compression wood. Compression wood was not observed in either the tap or any lateral roots further than 300 mm from the base of the stem. This suggests that either the roots do not experience the stresses required to induce compression wood formation, or that they lack the ability to form it. Roots artificially subjected to mechanical stress also failed to develop compression wood. It is therefore unlikely that an absence of a compressive load on buried roots can account for the lack of compression wood. Application of auxin to the cambia of lateral roots was similarly ineffective at inducing the formation of compression wood. These observations suggest that the buried roots of radiata pine lack the ability to develop compression wood. We also report the formation of an atypical S3 wall layer in the mechanically-stressed and auxin-treated tracheids and suggest that a reaction wood that is different to compression wood may well form in roots.


2009 ◽  
Vol 55 (No. 9) ◽  
pp. 415-422 ◽  
Author(s):  
V. Gryc ◽  
H. Vavrčík

The aim of research was to find out the variability of spruce (<I>Picea abies</I> [L.]) Karst.) wood compression strength limits in the direction parallel to grain. The wood strength was examined using samples from a tree with present reaction (compression) wood. The strength was found out for individual stem zones (CW, OW, SWL and SWR). The zone with present compression wood (CW) demonstrated slightly higher values of wood strength limits. The differences in the limits of compression strength parallel to grain in individual zones were not statistically significant. All the data acquired by measuring were used to create 3D models for each zone. The models describe the strength along the radius and along the stem height. The change of strength along the stem radius was statistically highly significant. There was an obvious tendency towards an increase in the strength limit in the first 40 years. With the increased stem height, there is a slight decrease in wood strength.


IAWA Journal ◽  
2017 ◽  
Vol 38 (2) ◽  
pp. 170-181 ◽  
Author(s):  
Jimmy Thomas ◽  
David A. Collings

We describe a novel, semi-automatic method for the detection, visualisation and quantification of axially oriented resin canals in transverse sections of Pinus radiata D. Don (radiata pine) trees. Sections were imaged with a flatbed scanner using circularly polarised transmitted light, with the resin canals that contained only primary cell walls appearing dark against a bright background of highly-birefringent tracheids. These images were analysed using ImageJ software and allowed for a non-biased, automated detection of resin canals and their spatial distribution across the entire stem. We analysed 8-month-old trees that had been subjected to tilting to induce compression wood and rocking to simulate the effects of wind. These experiments showed that both rocking and tilting promoted the formation of wood and confirmed that resin canals were most common adjacent to the pith. Both the rocking and tilting treatments caused a decrease in the number of resin canals per unit area when compared to vertical controls, but this change was due to the increased formation of wood by these treatments. In tilted samples, however, analysis of resin canal distribution showed that canals were more common on the lower sides of stems but these canals were excluded from regions that formed compression wood.


1973 ◽  
Vol 51 (3) ◽  
pp. 501-512 ◽  
Author(s):  
Richard T. Riding ◽  
Ernest M. Gifford Jr.

Histochemical tests on Pinus radiata shoot apices throughout the growing season showed marked changes in cell constituents. Reserve proteins and lipids were high in dormant embryos. Following imbibition, starch occurred throughout the apex and tannins were evident after the cotyledons emerged from the seed coat. Intensity of stains for DNA, RNA, and nucleohistones increased first at the flanks of the apex. At 84 days DNA, RNA, and histones displayed a zonate distribution pattern. Total proteins and carbohydrates were distributed fairly uniformly.The distribution of enzyme activity also varied. Initially acid phosphatase (AP) and succinic dehydrogenase (SDH) activities were high throughout the apex. A decrease of AP and SDH activity in the apex preceded epicotyl elongation. At 84 days AP activity differed in various regions of the apex; SDH was fairly uniform throughout the central, apical, and peripheral zones. Staining for peroxidase was evident first around aleurone grains and along cell walls after imbibition. With the onset of needle formation, staining was concentrated in subsurface cells. At 84 days peroxidase activity was concentrated in subsurface cells of the peripheral zone and in the rib meristem.The results of this study indicate that the full apex is metabolically active during vegetative growth and all regions are probably involved in the determination of vegetative form.


IAWA Journal ◽  
2014 ◽  
Vol 35 (2) ◽  
pp. 116-126 ◽  
Author(s):  
Haruna Aiso ◽  
Futoshi Ishiguri ◽  
Yuya Takashima ◽  
Kazuya Iizuka ◽  
Shinso Yokota

Anatomy and lignin distribution in artificially inclined stems of Sarcandra glabra were investigated to clarify the characteristics of reaction wood (RW) in a vessel-less angiosperm species. Of the five coppiced stems studied from a single tree, two stems were fixed straight and classified as normal wood (NW) and the remaining three stems were inclined at 50 degrees from the vertical to induce the formation of the RW. Compared with NW, the lower side of the inclined samples had a relatively high compressive surface-released strain and an increase in the microfibril angle of the S2 layer of tracheids. However, no significant change was observed in the length or cell wall thickness of the tracheids. The results of Wiesner and Mäule colour reactions indicated that the amount of guaiacyl lignin in the cell walls of tracheids was increased in RW. It appears that RW in Sarcandra is formed on the lower side of inclined stems, and its anatomical characteristics and chemical composition are similar to those of the compression wood (CW) found in gymnosperm species (the so-called “CW-like RW” type).


1999 ◽  
Vol 77 (1) ◽  
pp. 32-40 ◽  
Author(s):  
Adya P Singh ◽  
Lloyd A Donaldson

The structure of tracheid cell walls in mild compression wood of Pinus radiata D. Don was examined by confocal laser scanning fluorescence microscopy (CLSM) and transmission electron microscopy (TEM). Fluorescence microscopy using lignin autofluorescence revealed cell to cell variations in lignification of the cell corner middle lamella (CCML) and outer S2 (S2L) regions supporting observations made at higher resolution with TEM. The mild compression wood sample examined lacked the characteristic intercellular spaces of most grades of compression wood and thus represents the least severe grade of compression wood. TEM observations revealed evidence for radial striations in the S2 region probably representing regions of alternating high and low lignin concentration, which may be the precursor to the helical cavities found in severe compression wood. These radial striations typically showed a sinuous and branched structure, extending partly into the S2L region, where the orientation of lignin lamellae was predominantly tangential following the arrangement of the cellulose microfibrils. At high magnification lignin occurred in a patchy distribution overlaying the typical lamellate arrangement associated with normal wood. Significant variability in the lignification of the CCML region was also observed sometimes giving a patchy or granular appearance. The lignification of the CCML and the S2L regions was generally comparable, while S1 and S2 layers were less lignified. A residual S3 layer was sometimes present in the form of a very thin layer slightly more lignified than the adjacent S2 layer.Key words: compression wood, Pinus radiata D. Don, ultrastructure, confocal laser scanning microscopy, transmission electron microscopy, lignin distribution.


1950 ◽  
Vol 3 (1) ◽  
pp. 1 ◽  
Author(s):  
AB Wardrop ◽  
HE Dadswell

Optical and X-ray methQds have been used in the examinatiQn Qf the secQndarycell wall Qf cQmpressiQn WQQd tracheids from a number Qf species QfgymnDsperms.By these methQds it has been shQwn that the cell wall Qf CQmpressiQn WQQd tracheidscDnsists Qf two. layers. In the Quter layer the micelles are inclined at a large angle 'to. the lQngitudinal axis Qf the tracheid, while in the inner layer the micelles areinclined at a relatively smaller angle. In the inner Df the two. layers there exist radialdiscQntinuities in the spiral micellar structure, which are visible as IQngitudinal striatiQnsin the cell wall. These discQntinuities also. aCCQunt for the radial distributiQn Qflignin which is observed in transverse sectiQns Qf cQmpressiQn WQQd tracheids. Bydetermining the average tracheid length Qf the last-fDrmed late WQod in the variQusgrowth rings Df several eccentric stems Qf Pinus radiata D.DQn it has been shDwn thatthe tracheids Qf cQmpressiQn WQQd are appreciably shQrter than WQuld be the case ifno. cQmpressiQn WQQd were present. A study Qf the change in micellar QrientatiQn withchange in tracheid length has indicated that the angle Qf micellar QrientatiQn in CQmpressiQnWQQd tracheids dQes nQt differ signific(mtly frQm that existing in nQrmalWQQd tracheids Qf similar length. In so. far as the prQperties Qf WQQd are determinedby cell wall QrganizatiQn, it is cQncluded that cQmparisQns between cQmpressiQn WQDdand normal WQQd shQuld be made Qn material Qf the same tracheid length and spiralQrganizatiDn. It is suggested that bQth the reductiQn in tracheid length and eccentricradial growth in stems cQntaining cQmpressiQn WQQd are to. be attributed to. an increasein the number Df bDth transverse and tangential lQngitudinal divisiQns Qf thefusifQrm initials Qf the cambium.


1972 ◽  
Vol 20 (1) ◽  
pp. 9 ◽  
Author(s):  
G Scurfield

The results of extensive histochemical tests carried out on the walls of reaction wood cells in the stems of Eucalyptus spp. and Tristania conferta are presented. They are interpreted on the basis of the known chemistry and structure of such walls. These, in their turn, are related to the location of the cells in the stems. Of particular interest is the histochemical and structural heterogeneity of cell wall layer G. This heterogeneity is discussed in relation to the penetration of G by lignin precursors of extracellular origin and the possible release of phenolic substances from the protoplasts of living reaction wood, ray, and xylem parenchyma cells. The presence of peroxidase in the G layer is confirmed, and the marked tendency of G to stain when supplied with certain phenols and hydrogen peroxide demonstrated. Reduced lignification of G is tentatively attributed to retardation of lignin precursor penetration of G rather than to a lack of precursor availability.


2013 ◽  
Vol 40 (6) ◽  
pp. 637 ◽  
Author(s):  
Saori Sato ◽  
Hideto Hiraide ◽  
Masato Yoshida ◽  
Hiroyuki Yamamoto

Lignin is a major component of plant cell walls and is synthesised through oxidative polymerisation of monolignols. The transcription level of laccase, an enzyme implicated in monolignol polymerisation, is higher in the tissue forming compression wood than in normal wood. Compression wood, which is a special xylem tissue that develops to reorient inclined stems, also has a higher lignin content than normal wood. In the present study, Chamaecyparis obtusa Endl. saplings were grown on an incline and the following variables were tracked for 10 weeks: posture recovery of the saplings; development of xylem tissue on the lower side of inclined stems; and the transcription level of laccase. The posture of saplings approached vertical after 8 weeks, the development of compression wood reached a peak around 6 weeks and laccase transcription was the highest after 4 weeks. These results suggest a sequence of righting mechanisms. Inclination stimulates an increase in the abundance of laccase transcript and this increase encourages the formation of compression wood. The accumulation of compression wood then causes the stem to bend upward.


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