Retention of lignin in seagrasses:angiosperms that returned to the sea

Abstract

Using Curie-point Pyrolysis Gas Chromatography Mass Spectrometry [Py-GCMS) and Direct Temperature-resolved Mass Spectrometry (DT-bfS), lignin was detected In highly purified preparations (Milled Wood Lignin = hlWL) of various tissues of the seagrasses Zostera rnarina and Posidonia oceanica. The results ind~cate that P. oceanica contains more lign~n than Z. manna and that roots and rhizomes generally contain more Lignin than leaves. It is concluded that the ability to produce lignin is not lost by the angiosperm ancestors of extant seagrasses upon their colonization of the marine environment. Relative lignin abundances in the different tissues appear to be posltlvely correlated with life span. It is suggested that lignification contributes to the longevity of a tissue by protecting lt against microbial attack, but that deposition of lignin in seagrasses is restricted to tissues that show limited growth.