Cell Wall Morphogenesis and Structure in Tropical Tension Wood

Differentiating tension wood was observed in order to analyse the changes occurring during cell wall morphogenesis. Specimens were taken from trees in Guyana. Wall texture was analysed by means of ultrastructural cytochemistry. Modifications were encountered in fibre and vessel walls of tension wood when compared to typical wood. The changes were twofold: variation in the layering of polylamellate walls, and the deposition of a gelatinous layer in the fibre cell walls. Results are discussed in terms of variations in the rhythmic nature of cell wall deposition. Data confirm that the morphogenesis of the wall is a modular process allowing the cells to adapt to growth constraints.

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Cell Wall Layer Induced in Xylem Fibers of Flax Upon Gravistimulation Is Similar to Constitutively Formed Cell Walls of Bast Fibers

Frontiers in Plant Science ◽

10.3389/fpls.2021.660375 ◽

2021 ◽

Vol 12 ◽

Author(s):

Anna Petrova ◽

Liudmila Kozlova ◽

Oleg Gorshkov ◽

Alsu Nazipova ◽

Marina Ageeva ◽

...

Keyword(s):

Cell Wall ◽

Cell Walls ◽

Secondary Cell Wall ◽

Wall Layer ◽

Cell Wall Layer ◽

Wall Deposition ◽

Secondary Cell Walls ◽

Phloem Fibers ◽

Xylem Fibers ◽

Cell Wall Deposition

In the fibers of many plant species after the formation of secondary cell walls, cellulose-enriched cell wall layers (often named G-layers or tertiary cell walls) are deposited which are important in many physiological situations. Flax (Linum usitatissimum L.) phloem fibers constitutively develop tertiary cell walls during normal plant growth. During the gravitropic response after plant inclination, the deposition of a cellulose-enriched cell wall layer is induced in xylem fibers on one side of the stem, providing a system similar to that of tension wood in angiosperm trees. Atomic force microscopy (AFM), immunochemistry, and transcriptomic analyses demonstrated that the G-layer induced in flax xylem fibers was similar to the constitutively formed tertiary cell wall of bast (phloem) fibers but different from the secondary cell wall. The tertiary cell walls, independent of tissue of origin and inducibility, were twice as stiff as the secondary cell walls. In the gravitropic response, the tertiary cell wall deposition rate in xylem was higher than that of the secondary cell wall. Rhamnogalacturonan I (RG-I) with galactan side chains was a prominent component in cellulose-rich layers of both phloem and xylem flax fibers. Transcriptomic events underlying G-layer deposition in phloem and xylem fibers had much in common. At the induction of tertiary cell wall deposition, several genes for rhamnosyltransferases of the GT106 family were activated in xylem samples. The same genes were expressed in the isolated phloem fibers depositing the tertiary cell wall. The comparison of transcriptomes in fibers with both inducible and constitutive tertiary cell wall deposition and xylem tissues that formed the secondary cell walls is an effective system that revealed important molecular players involved in the formation of cellulose-enriched cell walls.

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Degradation of the Gelatinous Layer in Aspen and Rubberwood by the Blue Stain Fungus Lasiodiplodia Theobromae

IAWA Journal ◽

10.1163/22941932-90001471 ◽

1997 ◽

Vol 18 (2) ◽

pp. 107-115 ◽

Cited By ~ 5

Author(s):

Osvaldo Encinas ◽

Geoffrey Daniel

Keyword(s):

Cell Wall ◽

Cell Walls ◽

Tension Wood ◽

Soluble Carbohydrates ◽

Tropical Species ◽

Cell Wall Degradation ◽

Lasiodiplodia Theobromae ◽

Gelatinous Layer ◽

Weight Losses ◽

Blue Stain

Studies on the degradative ability of the blue stain fungus Lasiodiplodia theobromae (Pat.) Griffon ' Maublanc have shown several strains to cause significant weight losses (c. 20%) in wood of temperate and tropical species, aspen (Populus tremula) and rubberwood (Hevea brasiliensis), both species that commonly form tension wood. In addition to the consumption of soluble carbohydrates, major changes occurred in the ultrastructure of fibre cell walls, with a rapid attack of the G-layer of the gelatinous fibres. Following G-layer degradation, earlywood fibres of both species showed true cell wall degradation with pronounced erosion attack, suggesting that prior destruction of the G-layer afforded greater accessibility and ease of attack of the outer secondary cell wall layers.

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Sucrose‐enhanced reactive oxygen species generation promotes cotton fiber initiation and secondary cell wall deposition

Plant Biotechnology Journal ◽

10.1111/pbi.13594 ◽

2021 ◽

Author(s):

Xiaoyan Ding ◽

Xianbi Li ◽

Lei Wang ◽

Jianyan Zeng ◽

Liang Huang ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Cell Wall ◽

Cotton Fiber ◽

Secondary Cell Wall ◽

Reactive Oxygen Species Generation ◽

Reactive Oxygen ◽

Oxygen Species ◽

Fiber Initiation ◽

Wall Deposition ◽

Cell Wall Deposition

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The nature of reaction wood. IV. Variations in cell wall organization of tension wood fibres

Australian Journal of Botany ◽

10.1071/bt9550177 ◽

1955 ◽

Vol 3 (2) ◽

pp. 177 ◽

Cited By ~ 53

Author(s):

AB Wardrop ◽

HE Dadswell

Keyword(s):

Cell Wall ◽

Tension Wood ◽

Secondary Wall ◽

Degree Of Crystallinity ◽

Tropical Species ◽

Normal Wood ◽

Reaction Wood ◽

Gelatinous Layer ◽

Wood Fibres ◽

Cell Wall Organization

The cell wall organization, the cell wall texture, and the degree of lignification of tension wood fibres have been investigated in a wide variety of temperate and tropical species. Following earlier work describing the cell wall structure of tension wood fibres, two additional types of cell wall organization have been observed. In one of these, the inner thick "gelatinous" layer which is typical of tension wood fibres exists in addition to the normal three-layered structure of the secondary wall; in the other only the outer layer of the secondary wall and the thick gelatinous layer are present. In all the tension wood examined the micellar orientation in the inner gelatinous layer has been shown to be nearly axial and the cellulose of this layer found to be in a highly crystalline state. A general argument is presented as to the meaning of differences in the degree, of crystallinity of cellulose. The high degree of crystallinity of cellulose in tension wood as compared with normal wood is attributed to a greater degree of lateral order in the crystalline regions of tension wood, whereas the paracrystalline phase is similar in both cases. The degree of lignification in tension wood fibres has been shown to be extremely variable. However, where the degree of tension wood development is marked as revealed by the thickness of the gelatinous layer the lack of lignification is also most marked. Severity of tension wood formation and lack of lignification have also been correlated with the incidence of irreversible collapse in tension wood. Such collapse can occur even when no whole fibres are present, e.g. in thin cross sections. Microscopic examination of collapsed samples of tension wood has led to the conclusion that the appearance of collapse in specimens containing tendon wood can often be attributed in part to excessive shrinkage associated with the development of fissures between cells, although true collapse does also occur. Possible explanations of the irreversible shrinkage and collapse of tension wood fibres are advanced.

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