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  • 1
    Electronic Resource
    Electronic Resource
    Changes in the arrangement of cellulose microfibrils associated with the cessation of cell expansion in tracheids (1997)
    Springer
    Trees 11 (1997), S. 328-332 
    Details
    ISSN: 0931-1890
    Keywords: Key words Cellulose microfibril ; Tracheid ; Cell expansion ; Abies sachalinensis ; Secondary wall formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  The relationship between the cessation of cell expansion and formation of the secondary wall was investigated in the early-wood tracheids of Abies sachalinensis Masters by image analysis and field emission scanning electron microscopy. The area of the lumen and the length of the perimeter of the lumen of differentiating tracheids increased from the cambium towards the xylem. These increases had just ceased in the case of tracheids closest to the cambium in which birefringence was first detected by observations with a polarizing light microscope. Cellulose microfibrils (MFs) deposited on the innermost surfaces of radial walls were not well ordered during the expansion of cells, but well ordered MFs were deposited at the subsequent stage of cell wall formation. The first well ordered MFs were oriented in an S-helix. The well ordered MFs had already been deposited at the tracheids where birefringence was first detected under the polarizing light microscope. These results indicate that the deposition of the well ordered MFs, namely, the formation of the secondary wall, begins before the cessation of cell expansion of tracheids. Therefore, it seems that the expansion of tracheids is restricted by the deposition of the secondary wall because the cell walls become rigid simultaneously with the development of the secondary wall and, therefore, the yield point of cell walls exceeds the turgor pressure of the cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004680050092
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  • 2
    Electronic Resource
    Electronic Resource
    The effects of tracheid dimensions on variations in maximum density of Picea glehnii and relationships to climatic factors (2000)
    Springer
    Trees 14 (2000), S. 223-229 
    Details
    ISSN: 0931-1890
    Keywords: Key words Maximum density ; Cell wall thickness ; Radial cell diameter ; Climatic factors ; Picea glehnii Mast.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  An investigation was made of the effects of tracheid dimensions on variations in the maximum density of Picea glehnii Mast., which were associated with climatic changes. Radial cell diameter and the thickness of the tangential cell walls of the last-formed cells in 90 annual rings of nine trees with different annual ring widths were analyzed by image analysis. Correlations between maximum density and tracheid dimensions indicated that changes in maximum density were due mainly to changes in cell wall thickness of the last-formed cells in annual rings and were not due to changes in radial cell diameter. The effects of climatic factors on tracheid dimensions were examined by application of dendroclimatological techniques. A chronology of cell wall thickness that represented common signals among trees was established. Simple correlation and response function analyses of the chronology revealed that cell wall thickness was influenced positively by summer temperature and negatively by precipitation in August, and these responses were similar to those of maximum density. The study demonstrated that variations in maximum density were due to variations in the cell wall thickness of the last-formed cells, which varied depending on the weather in summer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00009766
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  • 3
    Electronic Resource
    Electronic Resource
    Dynamic changes in the arrangement of cortical microtubules in conifer tracheids during differentiation. (1995)
    Springer
    Planta 197 (1995), S. 418-421 
    Details
    ISSN: 1432-2048
    Keywords: Cortical microtubule ; Cellulose microfibril ; Abies ; Tracheid ; Confocal laser scanning microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The arrangement of cortical microtubules (MTs) in differentiating tracheids of Abies sachalinensis Masters was examined by confocal laser scanning microscopy after immunofluorescent staining. The arrays of MTs in the tracheids during formation of the primary wall were not well ordered and the predominant orientation changed from longitudinal to transverse. During formation of the secondary wall, the arrays of MTs were well ordered and their orientation changed progressively from a flat S-helix to a steep Z-helix and then to a flat S-helix as the differentiation of tracheids proceeded. The orientation of cellulose microfibrils (MFs) on the innermost surface of cell walls changed in a similar manner to that of the MTs. These results provide strong evidence for the co-alignment of MTs and MFs during the formation of the semi-helicoidal texture of the cell wall in conifer tracheids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00202666
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  • 4
    Electronic Resource
    Electronic Resource
    Orientation of microfibrils and microtubules in developing tension-wood fibres of Japanese ash (Fraxinus mandshurica var. japonica) (1995)
    Springer
    Planta 196 (1995), S. 577-585 
    Details
    ISSN: 1432-2048
    Keywords: Cellulose microfibril ; Cortical microtubule ; Fraxinus ; Gelatinous layer ; Tension-wood fibre
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The orientation of cellulose microfibrils (MFs) and the arrangement of cortical microtubules (MTs) in the developing tension-wood fibres of Japanese ash (Fraxinus mandshurica Rupr. var. japonica Maxim.) trees were investigated by electron and immunofluorescence microscopy. The MFs were deposited at an angle of about 45° to the longitudinal axis of the fibre in an S-helical orientation at the initiation of secondary wall thickening. The MFs changed their orientation progressively, with clockwise rotation (viewed from the lumen side), from the S-helix until they were oriented approximately parallel to the fibre axis. This configuration can be considered as a semihelicoidal pattern. With arresting of rotation, a thick gelatinous (G-) layer was developed as a result of the repeated deposition of parallel MFs with a consistent texture. Two types of gelatinous fibre were identified on the basis of the orientation of MFs at the later stage of G-layer deposition. Microfibrils of type 1 were oriented parallel to the fibre axis; MFs of type 2 were laid down with counterclockwise rotation. The counterclockwise rotation of MFs was associated with a variation in the angle of MFs with respect to the fibre axis that ranged from 5° to 25° with a Z-helical orientation among the fibres. The MFs showed a high degree of parallelism at all stages of deposition during G-layer formation. No MFs with an S-helical orientation were observed in the G-layer. Based on these results, a model for the orientation and deposition of MFs in the secondary wall of tension-wood fibres with an S1 + G type of wall organization is proposed. The MT arrays changed progressively, with clockwise rotation (viewed from the lumen side), from an angle of about 35–40° in a Z-helical orientation to an angle of approximately 0° (parallel) to the fibre axis during G-layer formation. The parallelism between MTs and MFs was evident. The density of MTs in the developing tension-wood fibres during formation of the G-layer was about 17–18 per μm of wall. It appears that MTs with a high density play a significant role in regulating the orientation of nascent MFs in the secondary walls of wood fibres. It also appears that the high degree of parallelism among MFs is closely related to the parallelism of MTs that are present at a high density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203659
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  • 5
    Electronic Resource
    Electronic Resource
    Freezing behavior of xylem ray parenchyma cells in softwood species with differences in the organization of cell walls (1999)
    Springer
    Protoplasma 206 (1999), S. 31-40 
    Details
    ISSN: 1615-6102
    Keywords: Freezing tolerance ; Xylem ray parenchyma cells ; Cell wall ultrastructure ; Supercooling ; Cryo-scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary By cryo-scanning electron microscopy we examined the effects of the organization of the cell walls of xylem ray parenchyma cells on freezing behavior, namely, the capacity for supercooling and extracellular freezing, in various softwood species. Distinct differences in organization of the cell wall were associated with differences in freezing behavior. Xylem ray parenchyma cells with thin, unlignified primary walls in the entire region (all cells inSciadopitys verticillata and immature cells inPinus densiflora) or in most of the region (mature cells inP. densiflora and all cells inP. pariflora var.pentaphylla) responded to freezing conditions by extracellular freezing, whereas xylem ray parenchyma cells with thick, lignified primary walls (all cells inCrytomeria japonica) or secondary walls (all cells inLarix leptolepis) in most regions responded to freezing by supercooling. The freezing behavior of xylem ray parenchyma cells inL. leptolepis changed seasonally from supercooling in summer to extracellular freezing in winter, even though no detectable changes in the organization of cell walls were apparent. These results in the examined softwood species indicate that freezing behavior of xylem ray parenchyma cells changes in parallel not only with clear differences in the organization of cell walls but also with subtle sub-electron-microscopic differences, probably, in the structure of the cell wall.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279251
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