Chemical composition of Casparian strips isolated from Clivia miniata Reg. roots: evidence for lignin

Abstract

Abstract. Endodermal cell walls and xylem vessels were isolated enzymatically from Clivia miniata Reg. roots. Transmission-electron-microscopic investigation of crosssections of intact C. miniata roots and scanningelectron-microscopic investigation of isolated endodermal cell walls indicated that the root endodermis of C. miniata is essentially in its primary state of development. Isolated Casparian strips and xylem vessels were subjected to two different degradation methods usually applied to prove the existence of lignin, namely, cupric oxide oxidation and thioacidolysis. The reaction products obtained were typical aromatic derivatives of the natural lignin precursors coniferyl and sinapyl alcohols, and, in traces, of p-coumaryl alcohol, indicating the occurrence of lignin in the polymers from both Casparian strips and xylem vessels. The qualitative chemical compositions of the polymers from the two sources were similar, whereas the quantitative compositions were different, indicating that the molecular structure of the lignin polymer in the Casparian strips was different from that in the xylem vessels. Thus, for the first time, direct chemical evidence has been obtained that Casparian strips of C. miniata roots contain lignin as a major cell wall polymer.

Apoplastic Diffusion Barriers in Arabidopsis

“…Schreiber et al used natural variations in endodermal development to analyze the endodermis in its primary developmental state, which is characterized by the sole presence of Casparian strips, in three species: Clivia miniata, Pisum sativum and Monstera deliciosa (Schreiber, 1996). This study demonstrated that lignin is the major polymer in the Casparian strips of these species.…”

Elevated atmospheric CO2, fine roots and the response of soil microorganisms: a review and hypothesis

“…Therefore, condensed tannin concentrations and lignin should increase as fine roots live longer, thereby causing a decline in the quality of substrates available for microbial growth. The relationship between longevity and the concentration of condensed tannins and lignin has been observed in the fine roots of trees and perennial herbs (McKenzie & Peterson, 1995a,b ;Schreiber, 1996) ; however, we are unaware of similar studies for annuals or perennial grasses. In some plants, fine roots can disappear well before the process of browning occurs (Hendrick & Pregitzer, 1992) and condensed tannins and lignin have accumulated.…”

“…Species-specific patterns of fine-root longevity could influence the types of substrate available for microbial metabolism in soil. As the ontogeny of an individual fine root progresses, cortical browning occurs (Hendrick & Pregitzer, 1992) owing to the deposition of condensed tannins (Richards & Considine, 1981 ;McKenzie & Peterson, 1995a,b) and lignin (Van Fleet, 1957 ;Schreiber, 1996). Therefore, condensed tannin concentrations and lignin should increase as fine roots live longer, thereby causing a decline in the quality of substrates available for microbial growth.…”

Casparian strip development and its potential function in salt tolerance

“…7 Several approaches have been used to better understand the structure and chemical composition of these specialized cell walls in many plant species. [8][9][10] A gas chromatography study showed that lignin was one of the major biopolymers in the Casparian strips of Clivia miniata roots, 11 while a different study comparing rice with corn demonstrated that rice roots show reduced apoplastic water permeability than corn roots, although the amount of suberin deposited in the root cell walls was not correlated with the differences in water and ion transport. 12 The characterization of the chemical composition of endodermal and hypodermal cell walls isolated from seven monocotyledonous and three dicotyledonous plant species indicated that isolated Casparian strips (primary endodermis) were strongly lignified.…”