Amino acid and sugar content of the nectar exudate from Limodorum abortivum (Orchidaceae). Comparison with Epipactis atropurpurea nectar composition

SUMMARY The amino acid content of nectary exudates from two orchids, L. nbortivum (spur nectary) and E. ati!optirpiti-ea (open nectary) were studied by means of capillary gas chromatography. Amino acids were analyzed as the corresponding N-heptafluorobutyryl isopropyl esters. For each amino acid, enantiomeric composition was achieved by gas chromatography of the N-pentafluoropropionyl isopropyl esters on a capillary coated with the chiral liquid phase Chirasil-Val. Comparison of the amino acid contents of both nectars, as well as the enantiomeric composition of the particular amino acids, indicate evolutionary differences of both nectaries. Gas chromatographic analysis of the nectar sugars, supports the conclusion that the open nectary of Epipacti,r atropbelongs to a more advanced evolutionary type compared to the spur nectary of Gimoclonun o6ot!)tnectar composition on pollinators is discussed.