scholarly journals Chemical composition, anatomy, lignin distribution, and cell wall structure of Malaysian plant waste fibers

BioResources ◽  
2006 ◽  
Vol 1 (2) ◽  
pp. 220-232 ◽  
Author(s):  
H. P. S. Abdul Khalil ◽  
M. Siti Alwani ◽  
A. K. Mohd Omar

The chemical composition, anatomical characteristics, lignin distribution, and cell wall structure of oil palm frond (OPF), coconut (COIR), pine-apple leaf (PALF), and banana stem (BS) fibers were analyzed. The chemical composition of fiber was analyzed according to TAPPI Methods. Light microscopy (LM) and transmission electron microscopy (TEM) were used to observe and determine the cell wall structure and lignin distribution of various agro-waste fibers. The results revealed differences in anatomical characteristics, lignin distributions, and cell wall structure of the different types of fibers investigated. Nevertheless, transmission electron microscopy (TEM) micrographs have confirmed that the well wall structure, in each case, could be described in terms of a classical cell wall structure, consisting of primary (P) and secondary (S 1 , S 2 , and S 3 ) layers.

Anatomical of cell wall structure on Schizostachyum brachycladum examined. The harvested two-year-old and four-year-old bamboo culms segregated into the bottom, middle and top portions. The samples then undergo the Light Microscopy (LM), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) to determine their structure such as a vascular bundle, parenchyma, and sclerenchyma. Results show the surface of bamboo was visualized by LM to decide on their structural figure. In this part, 2-year age indicated that higher numbers of vascular bundle and average of mean compared to the 4-year S. brachycladum. Followed by a specific study of cell wall structure using SEM with highlighted 4-year S. brachycladum had more complex of morphology structure compared to the 2-year-old. Later on, TEM illustrated to shows most depth anatomically structure of bamboo such as middle lamella, primary and secondary walls.


2013 ◽  
Vol 76 (8) ◽  
pp. 829-834 ◽  
Author(s):  
Celso Sant'Anna ◽  
Lilian T. Costa ◽  
Yuri Abud ◽  
Lucas Biancatto ◽  
Flávio Costa Miguens ◽  
...  

Holzforschung ◽  
2001 ◽  
Vol 55 (4) ◽  
pp. 373-378 ◽  
Author(s):  
Adya P. Singh ◽  
Geoffrey Daniel

Summary Transmission electron microscopy (TEM) of the walls of Picea abies axial tracheids showed the distribution of lignin in the S2 layer to be inhomogenous. At relatively low magnifications, some parts of the outer and inner S2 layer appeared more electron dense than the mid region in the tracheids which were in contact with or in proximity to a ray. At similar magnifications, the presence of radial and tangential features was observed in the S2 layer of the tracheids which were in contact with or close to rays as well as in those which occurred elsewhere. Higher magnification views showed the S2 layer to be differentiated into electron lucent and dense regions in both radial and tangential directions. A comparison of the counts made of lignin particles in these regions suggested that the differentiation of the S2 wall into lucent and dense regions resulted from inhomogenous distribution of lignin observable at a nano level.


2008 ◽  
Vol 47 (3) ◽  
pp. 273-280 ◽  
Author(s):  
H. P. S. Abdul Khalil ◽  
M. Siti Alwani ◽  
R. Ridzuan ◽  
H. Kamarudin ◽  
A. Khairul

2015 ◽  
Vol 229 ◽  
pp. 3-10 ◽  
Author(s):  
Bartłomiej Dybowski ◽  
Bogusława Adamczyk-Cieślak ◽  
Kinga Rodak ◽  
Iwona Bednarczyk ◽  
Andrzej Kiełbus ◽  
...  

The complex microstructure of as-cast AlSi7Mg alloy has been investigated. Microstructure observations were done using light microscopy, scanning electron microscopy and transmission electron microscopy. Chemical composition of the microstructure constituents was investigated by means of energy dispersive spectrometry, conducted both during SEM and STEM investigations. Selected area diffraction was used to identify the phases in the alloy. Microstructure of the alloy in the as-cast condition consists of Al-Si eutectic and intermetallic phases in the interdendritic regions. These are: Mg2Si, α-AlFeMnS, β-AlFeSi and π-AlFeSiMg phases. What is more, number of fine precipitates were found within the α-Al dendrites. Only the occurrence of U1 (MgAl2Si2) phase has been confirmed.


1997 ◽  
Vol 75 (5) ◽  
pp. 730-735 ◽  
Author(s):  
J. F. Bain ◽  
B. S. Tyson ◽  
D. F. Bray

The structure of the pollen wall as revealed by transmission electron microscopy is presented for 34 species representing two subtribes and 12 genera of New World Senecioneae. The genus Packera (=aureoid Senecio), with the exception of Packera zimapanica, is characterized by the helianthoid wall structure. In light of these results, the disposition of the latter species requires review. The genera Robinsonecio and Telanthophora of the subtribe Tussilagininae also possess helianthoid pollen. All other taxa surveyed have senecioid pollen. So far as known no taxa exist within the tribe Senecioneae with a base chromosome number of n = 20 and helianthoid pollen. This suggests that the evolution of Packera may have involved hybridization between members of the two subtribes Senecionineae and Tussilagininae. Key words: Asteraceae, Packera, Senecioneae, pollen, TEM, systematics.


2016 ◽  
Vol 13 (124) ◽  
pp. 20160645 ◽  
Author(s):  
Silvia Vignolini ◽  
Thomas Gregory ◽  
Mathias Kolle ◽  
Alfie Lethbridge ◽  
Edwige Moyroud ◽  
...  

The bright and intense blue-green coloration of the fruits of Margaritaria nobilis (Phyllanthaceae) was investigated using polarization-resolved spectroscopy and transmission electron microscopy. Optical measurements of freshly collected fruits revealed a strong circularly polarized reflection of the fruit that originates from a cellulose helicoidal cell wall structure in the pericarp cells. Hyperspectral microscopy was used to capture the iridescent effect at the single-cell level.


2009 ◽  
Vol 1184 ◽  
Author(s):  
Wolfgang Neumann ◽  
Holm Kirmse ◽  
Ines Häeusler ◽  
Changlin Zheng ◽  
Anna Mogilatenko

AbstractNanostructured materials from almost all classes of materials are of great interest because the reduced dimensionality may drastically change the physical properties. In general, these properties are a function of size, shape, arrangement and chemical composition of the nano-sized materials. Transmission electron microscopy (TEM) is a powerful tool to get a detailed insight into the material characteristics. To correlate microstructure as well as microchemistry and materials properties the various TEM techniques for imaging, diffraction and spectroscopy have to be combined. The potential applicability of quantitative TEM will be demonstrated for different nano-sized objects, particularly for semiconductor islands, nanowires, quantum dots and for soft magnetic materials. The classical diffraction contrast method of conventional TEM is applied to analyse the size, shape and arrangement of nano-sized structures, where a quantitative analysis often requires image simulations of diffraction contrast for theoretical structure models. An alternative and powerful method is the three-dimensional reconstruction of the shape from two-dimensional phase mapping by means of electron holography. This reqires the exact calculation of the mean inner potential of the specimen. Quantitative high-resolution transmission electron microscopy (qHRTEM) has to be applied to analyse structure and chemical composition on an atomic scale of magnitude. Particularly the application of aberration-corrected HRTEM offers new possibilities for quantitative structure analysis due to a contrast transfer by means of negative spherical aberration imaging (NCSI) and the resulting strong suppression of image delocalisation effects. An example for quantitative composition analysis will be demonstrated for ternary semiconductor quantum structures by means of a combined analysis of dark-field imaging and qHRTEM. The results will be compared with analytical TEM data (energy-dispersive X-ray spectroscopy (EDXS), electron energy-loss spectroscopy (EELS), and energy-filtered TEM (EFTEM)). The retrieval of chemical information with atomic resolution will be illustrated for III-V semiconductor nanostructures using STEM (scanning TEM) Z-contrast imaging. The correlation of structure and magnetic properties of soft magnetic materials will be demonstrated by combined application of Lorentz microscopy and electron holography. The potential applicability of the different quantitative TEM methods will be shown for following systems:(i) (Si,Ge) islands(ii) ZnTe and (Zn,Mn)Te nanowires(iii) Ga(As,Sb) quantum dots (QDs) on GaAs substrate(iv) nc softmagnetic FeCo alloysThe possibilities and limitations of the various methods applied will be critically evaluated.


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