Abstract
A survey of leaf soluble amino acids was conducted for four subtropical seagrasses grown at several salinities. Proline functioned as an organic osmoticum in Halodule wrightii Aschers., Thalassia testudinum Banks ex Koenig, and Ruppis maritima L., while alanine functioned in an osmoregulatory capacity in Halophila engelmanni Aschers. When light- and salinity-induced variations in leaf NH4 and amide-N levels were compared in Halodule, Thalassia, and Halophila, ability to regulate leaf NH4 levels was correlated with osmoregulatory capacity and maintenance of selected amino acid contents.
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