Analysis of Nitrogen and Amino Acid Contents in Cut and Potted Flowers of Eustoma grandiflorum

Abstract

The contents of total nitrogen and free amino acids of Eustoma grandiflorum were investigated during flower development and senescence in potted flowers, and were compared between potted and cut flowers, with or without sucrose supply. The total nitrogen content declined gradually as flower development and senescence proceeded in potted flowers. Detectable free amino acids by high performance liquid chromatography (HPLC) analysis in the petals were Asp, Glu, Asn, Gln, Ser, Phe, Gly, Thr, Ala, Tyr, and Val. The level of Gln was consistently high throughout flower development and senescence. Asn levels exhibited remarkable accumulation during flower senescence. The levels of other amino acids were much lower, but most showed a gradual increase until the initiation of wilting. Cut flowers without sucrose supply showed insufficient flower development and lower content of dry matter; however, total nitrogen content per corolla was not significantly different from potted flowers and cut flowers supplied with sucrose, resulting in a higher content of nitrogen per dry weight. These cut flowers without sucrose supply exhibited excessive accumulation of Asn and Gln at anthesis. Although nitrogen content per fresh weight or dry weight was slightly lower in the cut flowers with sucrose supply, their keeping quality was equivalent to potted flowers.