Limits...
Tracheid cell-wall structures and locations of (1   →   4)- β - d -galactans and (1   →   3)- β - d -glucans in compression woods of radiata pine ( Pinus radiata D. Don)

View Article: PubMed Central - PubMed

ABSTRACT

Background: Compression wood (CW) forms on the underside of tilted stems of coniferous gymnosperms and opposite wood (OW) on the upperside. The tracheid walls of these wood types differ structurally and chemically. Although much is known about the most severe form of CW, severe CW (SCW), mild CWs (MCWs), also occur, but less is known about them. In this study, tracheid wall structures and compositions of two grades of MCWs (1 and 2) and SCW were investigated and compared with OW in slightly tilted radiata pine (Pinus radiata) stems.

Results: The four wood types were identified by the distribution of lignin in their tracheid walls. Only the tracheid walls of OW and MCW1 had a S3 layer and this was thin in MCW1. The tracheid walls of only SCW had a S2 layer with helical cavities in the inner region (S2i). Using immunomicroscopy, (1 → 4)-β-D-galactans and (1 → 3)-β-D-glucans were detected in the tracheid walls of all CWs, but in only trace amounts in OW. The (1 → 4)-β-D-galactans were located in the outer region of the S2 layer, whereas the (1 → 3)-β-D-glucans were in the inner S2i region. The areas and intensities of labelling increased with CW severity. The antibody for (1 → 4)-β-D-galactans was also used to identify the locations and relative amounts of these galactans in whole stem cross sections based on the formation of an insoluble dye. Areas containing the four wood types were clearly differentiated depending on colour intensity. The neutral monosaccharide compositions of the non-cellulosic polysaccharides of these wood types were determined on small, well defined discs, and showed the proportion of galactose was higher for CWs and increased with severity.

Conclusion: The presence of an S3 wall layer is a marker for very MCW and the presence of helical cavities in the S2 wall layer for SCW. The occurrence and proportions of (1 → 4)-β-D-galactans and (1 → 3)-β-D-glucans can be used as markers for CW and its severity. The proportions of galactose were consistent with the labelling results for (1 → 4)-β-D-galactans.

Electronic supplementary material: The online version of this article (doi:10.1186/s12870-016-0884-3) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus

Immunofluorescence micrographs of transverse sections of OW and three CWs labelled with BS 400-2. OW (a) MCW1 (b), MCW2 (c) and SCW (d). In OW, there is very weak labelling of the tracheid walls (a). Computer enhanced brightening of the selected region (inset in a at the same scale) shows the S2 layer is the structure labelled. In MCW1, there is weak labelling of the inner region of the S2 layer (S2i) (b). This region is labelled brighter in MCW 2 (c). The brightest labelling is found in the same region in the SCW tracheid walls and is in the helical cavities. Sections were from Tree 1 and the micrographs obtained using a Leica confocal microscope. Scale bar: 10 μm
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC5015220&req=5

Fig5: Immunofluorescence micrographs of transverse sections of OW and three CWs labelled with BS 400-2. OW (a) MCW1 (b), MCW2 (c) and SCW (d). In OW, there is very weak labelling of the tracheid walls (a). Computer enhanced brightening of the selected region (inset in a at the same scale) shows the S2 layer is the structure labelled. In MCW1, there is weak labelling of the inner region of the S2 layer (S2i) (b). This region is labelled brighter in MCW 2 (c). The brightest labelling is found in the same region in the SCW tracheid walls and is in the helical cavities. Sections were from Tree 1 and the micrographs obtained using a Leica confocal microscope. Scale bar: 10 μm

Mentions: Immunofluorescence microscopy with the monoclonal antibody BS 400-2, which specifically recognizes (1 → 3)-β-glucans, showed very weak labelling of the tracheid walls in the OW (Fig. 5a). Computer enhanced brightening of the selected region of the image showed that the S2 tracheid wall layer was the structure labelled (see inset in Fig. 5a). The S2i region was weakly labelled in the MCW1 tracheid walls (Fig. 5b). This region was labelled brighter in the MCW2 tracheid walls (Fig. 5c), but the brightest labelling was in the same region of the SCW tracheid walls (Fig. 5d). In these SCW walls, the labelling was banded, corresponding to the helical cavities in this wall region. No labelling was found in micrographs from control experiments in which the primary antibody was omitted, or from control experiments using BS 400-2 that had been pre-incubated with laminarin.Fig. 5


Tracheid cell-wall structures and locations of (1   →   4)- β - d -galactans and (1   →   3)- β - d -glucans in compression woods of radiata pine ( Pinus radiata D. Don)
Immunofluorescence micrographs of transverse sections of OW and three CWs labelled with BS 400-2. OW (a) MCW1 (b), MCW2 (c) and SCW (d). In OW, there is very weak labelling of the tracheid walls (a). Computer enhanced brightening of the selected region (inset in a at the same scale) shows the S2 layer is the structure labelled. In MCW1, there is weak labelling of the inner region of the S2 layer (S2i) (b). This region is labelled brighter in MCW 2 (c). The brightest labelling is found in the same region in the SCW tracheid walls and is in the helical cavities. Sections were from Tree 1 and the micrographs obtained using a Leica confocal microscope. Scale bar: 10 μm
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5015220&req=5

Fig5: Immunofluorescence micrographs of transverse sections of OW and three CWs labelled with BS 400-2. OW (a) MCW1 (b), MCW2 (c) and SCW (d). In OW, there is very weak labelling of the tracheid walls (a). Computer enhanced brightening of the selected region (inset in a at the same scale) shows the S2 layer is the structure labelled. In MCW1, there is weak labelling of the inner region of the S2 layer (S2i) (b). This region is labelled brighter in MCW 2 (c). The brightest labelling is found in the same region in the SCW tracheid walls and is in the helical cavities. Sections were from Tree 1 and the micrographs obtained using a Leica confocal microscope. Scale bar: 10 μm
Mentions: Immunofluorescence microscopy with the monoclonal antibody BS 400-2, which specifically recognizes (1 → 3)-β-glucans, showed very weak labelling of the tracheid walls in the OW (Fig. 5a). Computer enhanced brightening of the selected region of the image showed that the S2 tracheid wall layer was the structure labelled (see inset in Fig. 5a). The S2i region was weakly labelled in the MCW1 tracheid walls (Fig. 5b). This region was labelled brighter in the MCW2 tracheid walls (Fig. 5c), but the brightest labelling was in the same region of the SCW tracheid walls (Fig. 5d). In these SCW walls, the labelling was banded, corresponding to the helical cavities in this wall region. No labelling was found in micrographs from control experiments in which the primary antibody was omitted, or from control experiments using BS 400-2 that had been pre-incubated with laminarin.Fig. 5

View Article: PubMed Central - PubMed

ABSTRACT

Background: Compression wood (CW) forms on the underside of tilted stems of coniferous gymnosperms and opposite wood (OW) on the upperside. The tracheid walls of these wood types differ structurally and chemically. Although much is known about the most severe form of CW, severe CW (SCW), mild CWs (MCWs), also occur, but less is known about them. In this study, tracheid wall structures and compositions of two grades of MCWs (1 and 2) and SCW were investigated and compared with OW in slightly tilted radiata pine (Pinus radiata) stems.

Results: The four wood types were identified by the distribution of lignin in their tracheid walls. Only the tracheid walls of OW and MCW1 had a S3 layer and this was thin in MCW1. The tracheid walls of only SCW had a S2 layer with helical cavities in the inner region (S2i). Using immunomicroscopy, (1 → 4)-β-D-galactans and (1 → 3)-β-D-glucans were detected in the tracheid walls of all CWs, but in only trace amounts in OW. The (1 → 4)-β-D-galactans were located in the outer region of the S2 layer, whereas the (1 → 3)-β-D-glucans were in the inner S2i region. The areas and intensities of labelling increased with CW severity. The antibody for (1 → 4)-β-D-galactans was also used to identify the locations and relative amounts of these galactans in whole stem cross sections based on the formation of an insoluble dye. Areas containing the four wood types were clearly differentiated depending on colour intensity. The neutral monosaccharide compositions of the non-cellulosic polysaccharides of these wood types were determined on small, well defined discs, and showed the proportion of galactose was higher for CWs and increased with severity.

Conclusion: The presence of an S3 wall layer is a marker for very MCW and the presence of helical cavities in the S2 wall layer for SCW. The occurrence and proportions of (1 → 4)-β-D-galactans and (1 → 3)-β-D-glucans can be used as markers for CW and its severity. The proportions of galactose were consistent with the labelling results for (1 → 4)-β-D-galactans.

Electronic supplementary material: The online version of this article (doi:10.1186/s12870-016-0884-3) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus