Cell walls lignified tissues

Comparison of the Overall Composition of Cell Wall Preparations. As can be seen from Table I, cell wall preparations showed a significant difference in their polymer composition. The endosperm cell walls resembled primary walls, since they were virtually free of lignin but rich in pectic substances. On the other hand, the cell wall preparations obtained from the caryopsis coat and the aleuron tissue were highly lignified, and their pectic content was very low. The germ cell wall showed a somewhat intermediate composition between these two types, probably reflecting the fact that it consists of several different tissues. 

Figure E3.1.2 (A) Hand-cut section from fresh apple tissue stained with phloroglucinol/HCl. Cell walls of the xylem tracheary elements (spirals) are stained red indicating they are lignified. (B) Increased magnification of A. (C) Hand-cut section from fresh pear tissue stained with phloroglucinol/HCl solution. Walls of the sclereid cells (stone cells center) are stained red indicating they are lignified. This black and white facsimile of the figure is intended only as a placeholder for full-color version of figure go to http //www.currentprotocols.com/colorfigures...

Cell Wall Material from Heavily Lignified Tissues... 

A range of methods have been described in the literature, and we shall consider them in the following order (1) the methods developed at the Food Research Institute-Norwich (FRIN), to isolate cell walls from a range of vegetables and fruits (runner beans, potatoes, cabbage and apples), cereals (oats, wheat and rye) and cereal products (wheat bran and rye biscuits), and lignified tissues (parchment layers of runner bean pods) (2) the special techniques, which may include wet sieving steps, used for the isolation of cell walls from potatoes, wheat endosperm, and wheat and barley aleurone layers (3) alternative methods for the isolation of cell walls from starch and protein-rich products (rice) and (4) methods used for the isolation of cell walls from suspension-cultured tissues. 

Feruloylated Pectins and Fendoylated Oligosaccharides. The cell walls of parenchymatous tissues of most grasses and some dicotyledons exhibit ultraviolet (uv) fluorescence (Harris and Hartley, 1981). The cell walls isolated from rapidly growing spinach cultures showed NH3-enhanced uv fluorescence (Fry, 1982b). We have found that the cell walls of parenchymatous (and lignified) tissues of sugar beet (root) and beetroot exhibited uv fluorescence. The cell walls isolated from parenchymatous tissues of beetroot also showed uv fluorescence. In contrast the cell walls of parenchymatous tissues of runner bean pods did not show uv fluorescence (R. R. Selvendran and P. Ryden, unpublished results). It would appear that the pectins (and other wall polymers) associated with ferulic and />-coumaric acids could be extracted from the cell walls of parenchymatous tissues (of dicotyledons) which exhibit uv fluorescence. 

---