N₂‐FIXATION (ACETYLENE REDUCTION) AND THE MICROBIAL COLONIZATION OF MANGROVE ROOTS

Abstract

S ummary Scanning and transmission electron microscopy were employed to study the microbial colonization of roots of three Florida mangrove species ( Rhizophora mangle, Avicennia germinans and Laguncularia racemosa ). Observations of ultrathin sections revealed that all three species were colonized in the outer cortical cell layers and that colonization was primarily limited to the mucigel layer and sloughing cells. Interpretation of these observations in relation to biological nitrogen fixation associated with roots of these species of intertidal halophytes is presented.