BIOSYNTHETIC INTERDEPENDENCE OF LIGNINS AND SECONDARY METABOLITES IN ANGIOSPERMS

The morphology and metabolism of angiosperms are connected to lignin p roduction. Morphology depends on the structure of genetically controll ed cellulose templates for lignin deposition; metabolism is the conseq uence of lignin-requirement directed biosynthesis of secondary metabol ites. Hence, it is possible to correlate morphological features (such as evolutionary replacement of woodiness by herbaceousness) with gener al chemical features (such as evolutionary replacement of aromatics by aliphatics) and with particular chemical features (such as oxidative diversification of biosynthetic categories of metabolites). The first correlation is useful for the systematic classification of plants at h igher levels (e.g. orders). The last correlation is useful for the evo lutionary assessment of plants at lower levels (e.g. families). These concepts allow the construction of an integrated system of angiosperm classification based on morphology for the circumscription of taxa and on chemistry for the evolutionary assessment of plant groups.