Differentiation tracheid

Figure 10. A differentiating tracheid stained with PATAg. Small circular vesicles (arrowheads), distributed near the ER are stained positively. The Golgi-vesicles are also stained positively. Abbreviations are as follows GV, Golgi-vesicle ER, endoplasmic reticulum. Scale bar is 500nm. (Reproduced with permission from Ref. 22. 1986, Japan Wood Research Society.)...

Accuracy of measurements in the middle lamella depends not only on Nb, but also on the value of Nd for this region. Donaldson (1985a) measured the refractive index of the middle lamella in differentiating tracheids before lignifica-tion and in primary xylem, where the middle lamella is unlignified, and obtained... 

Fujita M, Takabe T and Harada H (1983) Deposition of cellulose, hemicelluloses and lignin in the differentiating tracheids. International s miposium on wood and pulping chemistry, lapanese Technical Association of the Pulp and Paper Industry 1(2) 14-9... 

Porandowski J, Rakowski K, Wodzicki TJ (1982) Apical control of xylem formation in pine stems. II. Responses of differentiating tracheids. Acta Soc Bot Pol 51 187-201 Sachs T (1969) Polarity and induction of organized vascular tissues. Ann Bot 33 263-275 Schmid R (1965) The fine structure of pits in hardwoods. In Cote Jr (ed) Cellular ultrastructure of woody plants. Syracuse Univ Press, Syracuse, pp 291-304... 

Larson (4,5) fed 14C02 photosynthetically to Pinus resinosa, divided the differentiating xylem into several fractions, and counted the radioactivity of each cell wall component. From these studies, it was concluded that as tracheid maturation occurred, xylose deposition increased, whereas mannose remained relatively constant, and both arabinose and galactose decreased considerably. 

The process of differentiation that transforms primary cells into secondary cells is only partially understood. In such thick-walled cells as tracheids, fibers, and vessels in mature tissues, the greater part of the wall is made up of secondary thickening deposited after expansion of the primary wall has stopped. In cells that show localized growth (for example, tip growth), the secondary wall may well start to form in areas removed from the growing zone, while the latter is still active.2... 

Figure 10. Transverse section of coalified Cyrilla wood through wound tissue. Note differential response of the thick fiber wall layers to coalification. The outermost wall layers have produced an isotropic, orange-brown material whereas the bulk of the secondary wall has yielded a pale yellowy strongly anisotropic coal substance. A ring of dark red material has been produced from the inner secondary wall in the fiber-tracheid shown in the left center of the photograph and a semiopaque, granular product is seen in an adjacent iracheary element. 323X...

Minocha, S.C. and Halperin, W., Hormones and metabolites which control tracheid differentiation, with or without concomitant effects on growth, in cultured tuber tissue of Helianthus tuberosus L., Planta, 116, 319-331, 1974. 

Fig. 1-2. Transverse section of xylem and phloem of red spruce (P/cea rubens). CZ, cambial zone DP, differentiating phloem MP, mature phloem with sieve cells (sc) and tannin cells (tc) DX, differentiating xylem with ray cells and tracheids (tr) MX, mature xylem, earlywood (EW) with resin canals (rc), lined with epithelial cells (ec) LW, latewood. Note that each ray continuous from the xylem, through the cambial zone, and into the phloem. Light micrograph by L. W. Rees. Courtesy of Dr. T. E. Timell.

Fig. 7.4 A-C. A model of control of morphogenesis by vectors of auxin wave propagation in the final phase (autolysis) of axial tracheid maturation in secondary xylem of the stem. A Trajectories of vectors of auxin wave propagation (a) in the cambial region and in differentiating secondary tissues as seen in radial (b) and transverse (c) sections. The breakdown of the cytoplasm is initiated when some critical angle (a) between the vector of auxin wave propagation and the cell axis is attained. B and C Vector trajectories associated with a model of regulation of earlywood and latewood differentiation. Ph conducting phloem Ph dividing phloem Cj cambial initial dividing xylem ...

II. Dependence upon basipetal transport. Physiol Plant 29 288-292 Wodzicki TJ, Wodzicki AB (1980) Seasonal abscisic acid accumulation in stem cambial region of Firms silvestris and its contribution to the hypothesis of a late-wood control system in conifers. Physiol Plant 48 443 47 Wodzicki TJ, Wodzicki AB (1981) Modulation of the oscillatory system involved in polar transport of auxin by other phytohormones. Physiol Plant 53 176-180 Wodzicki TJ, Zajqczkowski S (1974) Effect of auxin on xylem tracheid differentiation in decapitated stems of Firms silvestris L. and its interaction with some vitamins and growth regulators. Acta Soc Bot Pol 43 129-148 Wodzicki TJ, Wodzicki AB, Zajqczkowski S (1979) Hormonal modulation of the oscillatory system involved in polar transport of auxin. Physiol Plant 46 97-100 Wodzicki TJ, Rakowski K, Starck Z, Porandowski J, Zajqczkowski S (1982) Apical... 

The xylem with the trachea and tracheids which are directly important for the conduction of materials. They are dead in the completely differentiated state but cannot maintain their function without living xylem parenchymal cells which surround them. 

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