Some pertinent results and views from the earlier history of lignin chemistry, pointing to the importance of the arylpropane skeleton, are outlined. Later development, beginning with the dehydrogenation theory and experimental studies on the dehydrogenative polymerization of p-hydroxycinnamyl alcohols, is then reviewed. Finally, recent degradative work resulting in a detailed picture of lignin structure is discussed.

Lignin chemistry—past, present and future

This review deals with the formation of lignin as a mechanism of resistance to plant disease. Lignin is one of the most abundant biopo1ymers on earth (120, 140) and is resistant to degradation by most microorganisms (83,84). It is thought to be formed commonly as a response to microbial penetration and mechanical damage (51, 71, 111, 140), but the role of lignification in disease resistance has been investigated in only a limited number of cases. The possible specificity of lignin formation in disease resistance remains unresolved.

Lignification as a Mechanism of Disease Resistance

In the twelve years since the first review article dealing with chemical constituents of the Hepaticae appeared in this series as Volume 42 (19), several short reviews concerned with chemical constituents of bryophytes have been published (22, 96, 144, 265, 271, 647, 649, 650) In 1988, a Symposium on Chemistry and Chemical Taxonomy of Bryophytes was organised on the behalf of the Phytochemical Society of Europe; the proceedings of this meeting appeared as a book entitled Bryophytes: Their Chemistry and Chemical Taxonomy (651) The symposium concerned itself with phytochemical, biochemical, botanical, chemotaxonomical, pharmaceutical, biotechnological and environmental aspects of bryophytes as well as with the synthesis of the terpenoids and aromatic compounds bryophytes elaborate The physiological and biochemical aspects of bryophytes have also been described in a recent book Bryophytes Development: Physiology and Biochemistry (139)

Chemical Constituents of the Bryophytes

Lignans are phenylpropanoid dimers, where the phenylpropane units are linked by the central carbon (C8) of their side chains. Ligans vary substantially in oxidation level, substitution pattern, and the chemical structure of their basic carbon framework. In addition to structural diversity, lignans show considerable diversity in terms of enantiomeric composition, biosynthesis, and phylogenetic distribution. In this review, these diversities are outlined and the phylogenetic distribution of plants producing 66 typical lignans is listed. The distribution is correlated with the putative biosynthetic pathways of the lignans and discussed from evolutionary aspects. 
Abbreviations: SIRD – Secoisolariciresinol dehydrogenase; PLR – pinoresinol lariciresinol reductase; DP – dirigent protein

Diversity in lignan biosynthesis

1. Climate change in the subarctic is expected to influence vegetation composition, specifically bryophyte and lichen communities, thereby modifying litter decomposition rates and carbon (C) dynami ...

https://besjournals.onlinelibrary.wiley.com/doi/epdf/10.1111/j.1365-2745.2009.01538.x

An experimental comparison of chemical traits and litter decomposition rates in a diverse range of subarctic bryophyte, lichen and vascular plant species

G.E. Miksche

Papers

On the occurrence of lignin or polyphenols in some mosses and liverworts