DETERMINATION OF 1-AMINOCYCLOPROPANE-1-CARBOXYLIC ACID (ACC) IN LEAF TISSUE AND XYLEM SAP USING CAPILLARY COLUMN GAS-CHROMATOGRAPHY AND A NITROGEN PHOSPHORUS DETECTOR

The Lizada and Yang method, commonly used for analyzing 1-aminocyclopr opane-1-carboxylic acid (ACC), the immediate precursor of the plant ho rmone ethylene, is subject to interference and lacks internal standard s. The use of combined gas chromatography-mass spectrometry (GC-MS) ov ercomes these short-comings but the method is expensive and unavailabl e to many laboratories. We describe an alternative physico-chemical me thod using a capillary column gas chromatograph fitted with a standard nitrogen phosphorus detector. After forming the N-benzoyl n-propyl de rivative, measurements of ACC concentrations in extracts of leaves and in xylem sap of tomato plants using the nitrogen/phosphorus detector were within 10% of those obtained by GC-MS. Concentrations in plants g rown in well-drained soil were approximately 0.16 nmol g-1 fresh weigh t (leaves) and 0.04-0.01 mmol m-3 (sap). Flooding the soil for 48-72 h increased these values approximately 9-fold.