Contact information: a: Department of Applied Physics, Aalto University, P.O. Pulp and Paper Fundamental Research Symposia Proceedings, This review demonstrates the importance and potential use of TEM in the investigation of wood and fiber cell wall ultrastructure. 46(12), 5113-5117. 1971). “Use of soft rot fungi for studies on the microstructure of kapok (Ceiba pentandra (L.) Gaertn.) DOI: 10.1021/sc400470m, Reza, M., Ruokolainen, J., and Vuorinen, T. (2014b). DOI: 10.1093/jxb/14.3.496, Highley, T. L., Murmanis, L., and Palmer, J. G. (1983). Daniel, G., Goodell, B., Jellison, J., Paszczynski, A., and Crawford, R. (1991). The compound middle lamellae (CML) region has dark contrast showing the spot of high lignin content. X-ray tomography on spruce wood has been produced; however, researchers were only able to observe the features with dimensions over 1.5 µm (Trtik et al. DOI: 10.1126/science.179.4074.647, Singh, A. P., and Daniel, G. (2001). The explanation behind such structures is unclear in the literature. 85(2), 257-266. (2003). They also found a heterogeneous lignin distribution in the middle lamella attached to the fiber surface. The analytical potential of TEM can essentially be amplified using complementary instruments, and thus these will also be briefly reviewed. Br. Carrière] by immunofluorescence,” Holzforschung 61(3), 311-316. 1998). DOI: 10.1016/j.indcrop.2010.11.009. 2000; Kim et al. “Uber Fortschritte im Bau und in der Leistung des magnetischen Elektronenmikroskops (On the progress in the construction and performance of the magnetic electron microscope),” Z. Phys. “Recent progress in the chemistry and topochemistry of compression wood,” Wood Sci. DOI: 10.1016/S0168-1656(97)01674-X, Blanchette, R. A., Obst, J. R., and Timell, T. E. (1994). Z. Forstwes. However, this method cannot distinguish between two cell types with different microfibril angles (MFA), or even one cell type showing two MFAs; therefore, the benefit of averaging over several cells requires some previous knowledge about the system. Fig. 1986). DOI: 10.1038/162665a0, Preston, R. D., and Ripley, G. W. (1954). The degradation/alteration of CML lignin was reported in thermally modified wood (Gao et al. Atomic force microscopy (AFM) has been used as an important complement to electron microscopy to study the wood ultrastructure for a prolonged duration (Fahlén and Salmén 2005; Zimmermann et al. The application of electron diffraction on algal cellulose microfibrils provided details of cellulose polymorphism and crystal structure (Preston and Ripley 1954; Sugiyama et al. 2006). Lautner, S., Zollfrank, C., and Fromm, J. It has been suggested that this epitope has a role in cross-linking the secondary wall with the GL (Arend 2008). “A contribution to the ultrastructure of tension wood fibers,” Wood Sci. They really wrote this with the student in mind. To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. DOI: 10.1021/ma00009a050, Sugiyama, J., Vuong, R., and Chanzy, H. (1991b). However, microfibrils perpendicular with respect to the fiber longitudinal axis in single helix have been observed in recent studies (Brändström et al. 1999). 1990, 1991, 2004; Kim et al. DOI: 10.1016/j.jsb.2007.02.003, Wada, M., Okano, T., Sugiyama, J., and Horii, F. (1995). Later, the development of replication, ultramicrotomy, and embedding in resin added the flexibility of studying small specimens extracted from a whole tree. 2009). “Heterogeneity in formation of lignin-XI: An autoradiographic study of the heterogeneous formation and structure of pine lignin,” Wood Sci. Some additional features of TEM, such as acquiring tilt series, EDX, EELS, and diffraction are promising complementary features which have provided additional information about the wood structure. More systematic studies using high-resolution imaging techniques are required to fully understand the structure of microfibrils and their orientation in native cell walls. This review describes use of transmission electron microscopy (TEM) in wood and fiber analysis. 2003; Reza et al. (1993). Wood Ultrastructure: An Atlas of Electron Micrographs, University of Washington Press. The nitrogen in the resin produced detectable signals in all the layers of the lignified cell walls, thus allowing for the quantification of resin that had penetrated into the different layers. The primary cell wall (P) has the lowest labeling intensity and the S1 and S2 layers have the highest labeling intensity. Arrow shows a characteristic helical check. “Reaction wood: Its structure and function: Lignification may generate the force active in restoring the trunks of leaning trees to the vertical,” Science 179(4074), 647-655. The basic principles for image formation using TEM are described in Williams and Carter (2009). An unoriented amorphous material gives a diffraction pattern consisting of broad rings, which poses difficulty to extract diffraction of the crystalline structure. Several sophisticated microscopy and spectroscopy techniques are available, providing high-resolution information about wood cells at the molecular level; e.g., Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), X-ray methods, and Raman microspectroscopy are routinely used for wood research (Abe et al. 2010a, b). Laccase (La), manganese peroxidase (MnP), and lignin peroxidase (LiP) enzymes were found associated with the degraded cell-wall, as well as the extracellular slime material. Lastly, a comparison between TEM and other imaging techniques used for wood and fiber research are made. Kim, Y. S., Choi, J. H., and Bae, H. J. Nevertheless, the mapping of specimens can be disturbed by laser induced damage and excess fluorescence (Gierlinger et al.