– Description:
– Plant cuticle is a layer of lipid polymers with waxes on outer surfaces of vascular land plants.
– Present in sporophyte generation of hornworts and mosses.
– Can be isolated intact with enzymes like pectinase and cellulase.
– Forms coherent outer covering of the plant.
– Composition:
– Composed of insoluble cuticular membrane with soluble waxes.
– Cutin, a polyester polymer, is a key structural component.
– Contains non-saponifiable hydrocarbon polymer Cutan.
– Impregnated with cuticular waxes and epicuticular waxes.
– Cuticular wax biosynthesis:
– Composed of compounds derived from very-long-chain fatty acids.
– Includes terpenoids, flavonoids, and sterols with different synthetic pathways.
– Initial step occurs with de novo biosynthesis of C16 acyl chains.
– Fatty acid elongase complex is an important catalyzer.
– Functions:
– Acts as a water permeability barrier to prevent water loss.
– Micro and nano-structure prevent contamination of plant tissues.
– Dehydration protection improves offspring fitness.
– Functions in defense against viruses, bacteria, and fungi.
– Evolution:
– Plant cuticle is part of innovations plants evolved over 450 million years ago.
– Together with stomata, xylem, and phloem, it enabled plants to conserve water.
– Features include gas exchange surface internalization and stomatal guard cells.
A plant cuticle is a protecting film covering the outermost skin layer (epidermis) of leaves, young shoots and other aerial plant organs (aerial here meaning all plant parts not embedded in soil or other substrate) that have no periderm. The film consists of lipid and hydrocarbon polymers infused with wax, and is synthesized exclusively by the epidermal cells.
