Analysis of polyamines, 1-aminocyclopropane-1-carboxylic acid and their conjugated forms in floral organs of Hibiscus syriacus L.

摘要

A convenient method was devised for the fractionation of aliphatic polyamines (PAs), 1-aminocyclopropane-1-carboxylic acid (ACC), and their conjugated forms using a cation exchange resin, and applied to the floral organs of Hibiscus syriacus cv. Diana. A batch-wise use of the cation exchange resin to the acid extracts of the Hibiscus flower effectively separated the ACC-conjugate from free ACC, free PAs, and PA-conjugates. Good recovery rates, showing over 90% for PAs and 76-97% for ACC, were obtained when known amounts of ACC and PAs were added to the tissue extract. The amounts of these cellular compounds were determined in the petal, sepal, ovary, and style with stigma (+stamen) collected at two different stages (flower opening and flower senescence showing complete petal in-rolling). Both ACC and ACC-conjugate, which are generally associated with tissue senescence, were consistently detected in all organs even immediately after flower opening, but their concentrations, especially that of the ACC-conjugate in the ovary, greatly increased in the senescent flowers. As regards the free PA levels, a high concentration of spermidine was found in the ovary, and its level was maintained even when the petals wilted. PA-conjugates bound to small molecules decreased in the ovaries of senescent flowers, while the PA-conjugates bound to macromolecules remained very low in all organs at the two different flower stages. The present method seems applicable to a quantitative analysis of these physiologically important compounds in a variety of plant tissues, despite the fact that their extracts contain highly viscous materials that generally reduce the recovery rate of ACC..