Suberization as a Means of Compartmentalization

Suberin is laid down in various internal locations in order to seal off specific regions of the plant (234). In the primary development of plant roots, suberin is deposited in the Casparian band of endodermal cells (45, 103, 162, 317, 364, 367, 369, 474, 483). The presence of suberin in the Casparian band of the endodermis of Sorghum bicolor was shown chemically by depolymerization (244). Suberized layers are also found in the mestome sheath and bundle sheath cell walls of grasses (52, 61, 108, 118, 171, 172, 331, 368), and these layers have been chemically characterized in Zea mays and Secale cereale (114, 146). 

Ultrastructural studies indicated that suberin is deposited in seeds, when they reach maturity, as a means of sealing off the seed where vascular tissue was attached. Thus suberin was shown to be deposited in the pigment strand of Triticum 

Suberin is laid down in the cell wall of calcium oxalate crystal idioblasts. This deposition has been characterized in crystal cells in the bark of Larix decidua, Acacia Senegal, and Picea abies (481, 482). The suberin in crystal idioblast cell walls from Agave americana was characterized both ultrastructurally (Fig. 6.4.3) and chemically, and the major aliphatic component was shown to be octadocenedioic acid (25%) (117). The basal walls of leaf trichomes are suberized as shown in Abutilon megapotamicum (161), Ananas comosus (395), and Larrea tridentata (451). The walls of oil cells found in Acorus calamus (9) and Laurus nobilis (291) also appear ultrastructurally to be suberized. Suberized cells encircle silica cells in the stem of Lolium temulentum (271). In all of the cases listed above, the suberin may serve to protect the rest of the plant from potentially toxic components. 

---