BIOGEOGRAPHIC VARIATION IN FOLIAR WAXES OF MANGROVE SPECIES

Foliar epicuticular wax composition of mangrove species with natural d istributions in West Africa and the Atlantic coast of South America, w as studied by GC in order to investigate possible biogeographic variat ion. South American (Guyana) populations of Avicennia germinans were v ery much poorer in triterpenoids and in C-32 alkane and richer in C-28 alkane than populations from West Africa (Gabon). Shrub forms of A. g erminans were richer in triterpenoids than trees. Dwarf forms of Conoc arpus erectus were much poorer in triterpenoids, than shrub forms of t his species. The pattern of alkane composition in Rhizophora from Guya na was unimodal, with unusually high amounts of C-28, contrasting with a bimodal pattern, with modes at C-28-C-29 and C-31, in Rhizophora fr om Gabon. Foliar wax of Laguncularia racemosa from Guyana contained on ly trace amounts of triterpenoids and a broad range of alkanes with mo des at C-29 and C-33, whereas triterpenoids were present in significan t amounts and most of the alkane fraction consisted of C-27-C-29 in Ga bon. These preliminary data suggest significant biogeographic variatio n within these taxa. Copyright (C) 1996 Elsevier Science Ltd.