Lignifisertevev

Lignifisertevev refers to plant tissue in which cells have lignified their walls by deposition of lignin, a complex aromatic polymer. Lignification strengthens support, increases mechanical stiffness, and makes cell walls more resistant to decay and water penetration. It is common in vascular plants, particularly in xylem elements such as tracheids and vessel elements and in sclerenchyma fibers, and is a hallmark of most woody tissues. In contrast, many parenchyma and other primary tissues remain non-lignified or only lightly lignified.

Biochemically, lignin is produced through the phenylpropanoid pathway. Monomers—p-coumaryl, coniferyl and sinapyl alcohols—are transported to developing cell walls and polymerized by oxidative enzymes, notably peroxidases and laccases, forming a heterogeneous, cross-linked network that fills the secondary cell wall.

Development and location: Lignification typically occurs as part of secondary cell wall formation after cell elongation. The resulting lignified tissues are largely dead at maturity (e.g., tracheary elements and sclerenchyma fibers), though some living cells may retain limited metabolic activity in their lignified portions.

Functions and significance: Lignified tissue provides mechanical support for standing plants and serves as a rigid scaffold for efficient water transport in the xylem. It also reduces permeability to pathogens and contributes to wood durability. Economically, lignin is a major component of wood and bark, influencing properties relevant to timber processing and bioenergy.

Detection: In histology, lignin is commonly detected with stains such as phloroglucinol-HCl, which yields a red color, and Mäule staining, which can indicate lignin composition.