Investigating the Leaf Cuticle of the Moss Physcomitrella Patens

Abstract

To minimize water loss, the aerial parts of vascular land plants are covered with a hydrophobic layer called a cuticle. The cuticle typically consists of two major components: cutin and waxes. In contrast to vascular plants, research reports indicate that some primitive nonvascular plants, such as mosses, lack a cuticle. This study attempts to reconcile contradictory literature reports about the presence of a waxy cuticle on the leaves of the moss Physcomitrella patens.Histochemical staining was utilized to investigate the presence of a cuticle on Physcomitrella leaves. Experiments employing dyes that stain hydrophobic substances were generally consistent with the presence of a cuticle. Hydrophilic dyes were also used to infer the presence of a cuticle through an absence of staining. Histochemical results were supported by observations made using freeze fracture electron microscopy. Leaves consistently fractured through an extracellular layer having a rippled texture, which resembling cuticles known to occur in vascular plants. Attempts to isolate a cuticle from Physcomitrella leaves by partial digestion with chromic acid or treatment with polysaccharide-degrading enzymes were also successful.

Phytochemical Exploration of Ceruchinol in Moss: A Multidisciplinary Study on Biotechnological Cultivation of Physcomitrium patens (Hedw.) Mitt.

“…Additionally, the presence of C16 and C18 fatty acids may imply their involvement as promoters for the cutin layer, among other functions. The identification of indole-3-acetic acid (IAA), a type of auxin, further emphasizes the nuanced interplay of hormonal and structural factors contributing to the development of wax layers in P. patens gametophores [22,23,25,26,42].…”

“…Furthermore, potential substrates or products of suberin polymerization [42] were detected in the extract, including derivatives of cinnamic acid, long-chain aldehydes, and secondary alcohols. This finding provides additional support for our assumption regarding the composition of the protonemata and gametophores of P. patens, reinforcing the notion that the moss may exhibit a complex makeup involving these identified compounds.…”