Composition and ultrastructure of the suberized cell wall of isolated crystal idioblasts from Agave americana L. leaves

Abstract

Styloid-calcium-oxalate-crystal-containing idioblasts possess an interior cell-wall layer which has a lamellar ultrastructure. Idioblasts were isolated by centrifugation of an Agave americana leaf homogenate through 2M sucrose. The aliphatic monomers of the polymeric material from an idioblast fraction were primarily ω-hydroxy acids (32%) and dicarboxylic acids (35%), with C18:1 dicarboxylic acid being the most dominant monomer (25%). Nitrobenzene oxidation of the idioblasts yielded syringaldehyde and vanillin in a ratio of 0.46:1. The major class of wax associated with the idioblasts was free fatty acids (34%). A major homologue of both the fatty acid and fatty alcohol fractions of this wax was C22. The hydrocarbon fraction of the wax had a broad chainlength distribution with a large amount of even-numbered (47%) and shorter-chain homologues. The ultrastructure, the composition of the aliphatic and aromatic components of the polymeric material as well as the composition of the wax show that the idioblast cell wall is suberized. The wax and cutin polymer of the epidermis of A. americana leaves were chemically characterized for comparative purposes.

Magnesium Deficiency Results in Increased Suberization in Endodermis and Hypodermis of Corn Roots

“…However, little direct evidence is available concerning the nature of the intermonomer linkages present in the aromatic domain. The release of aromatic aldehydes, particularly p-hydroxybenzaldehyde and vanillin, by alkaline nitrobenzene oxidation appears to be a characteristic feature of suberin and the quantity of the aldehydes appears to be a measure of the aromatic domains of suberin (3,9). In the present case, roots grown in normal Mg2+ concentration gave rise to p-hydroxybenzaldehyde and vanillin with much smaller quantities ofsyringaldehyde.…”

“…Electron micrographs of suberin reveal a lamellar structure composed of light and dark bands probably representing alternating layers of wax and polymer (23,24). Suberin, which has been ultrastructurally identified, has been examined chemically from only a few sources (5,8,9), but in these cases the composition of the aliphatic components agreed well with an early generalization that long chain (C,6-C26) w-hydroxy and dicarboxylic acids are very often the major aliphatic components of suberin (16 cells (19,20), suberin in roots has been examined chemically in only a few cases (7,14,18). Suberization in the plant may frequently be a response to certain types of stress, but there have been no combined chemical and ultrastructural studies on the effects of such stress upon suberization in roots.…”

Ultrastructural and Chemical Evidence That the Cell Wall of Green Cotton Fiber Is Suberized

“…Although the aromatic domains of suberin have not been well defined (9), release of p-hydroxybenzaldehyde and vanillin by nitrobenzene oxidation has been found to be a characteristic of such suberin domains (3,7). The observed release of 12 times as much vanillin and p-hydroxybenzaldehyde from the polymer of the green cotton as from the white cotton is, therefore, an additional indication that the cell walls of the green fibers are suberized.…”

A Review of Macromolecular Organic Compounds That Comprise Living Organisms and Their Role in Kerogen, Coal, and Petroleum Formation

“…Suberins are mainly present as wall components of cork cells, comprising the periderm layers of both aerial and subterraneous parts of woody plants. They also occur in the cell walls of specialized internal tissues such as in the endodermis (Casparian bands) (Robards et aI., 1973), bundle sheaths of grasses (O'Brian and Carr, 1970), and cell walls of calcium oxalate crystals isolated from leaf homogenates (idioblasts) (Espelie et al, 1982). In cork, suberins can account for 30-35% of the dry weight.…”