Ethylene and 1 -Aminocyclopropane-1-Carboxylic Acid Production inflacca, a Wilty Mutant of Tomato, Subjected to Water Deficiency and Pre-treatment with Abscisic Acid

Abstract

Neill, S. J., McGaw, B. A. and Horgan, R. 1986. Ethylene and 1-aminocyclopropane-l-carboxylic acid production in flacca, a wilty mutant of tomato, subjected to water deficiency and pretreatment with abscisic acid.—J. exp. Bot. 37: 535-541. Plants of Lycopersicon esculentum Mill. cv. Ailsa Craig wild type and flacca (flc) were sprayed daily with H20 or 2x 102 mol m3 abscisic acid (ABA). ABA treatment effected a partial phenotypic reversion offlc shoots; leaf areas were increased and transpiration rates decreased. Leaf expansion of wild type shoots was inhibited by ABA. Indoleacetic acid (IAA), ABA and 1-aminocyclopropane-l-carboxylic acid (ACC) concentrations were determined by combined gas chromatography-mass spectrometry using deuterium-labelled internal standards. ABA treatment for 30 d resulted in greatly elevated internal ABA levels, increasing from 10 to 4-3 and from 0-45 to 4-9 nmol g1 fr. wt. in wild type and flc leaves respectively. Endogenous IAA and ACC concentrations were much lower than those of ABA. IAA content ranged from 0 05 to 01 nmol g~1 and ACC content from 0 07 to 0-24 nmol g~ '. Ethylene emanation rates were similar for wild type and flc shoots. Wilting of detached leaves induced a substantial increase in ethylene and ACC accumulation in all plants, regardless of treatment or type. Ethylene and ACC levels were no greater in flc leaves compared to the wild type. ABA pretreatment did not prevent the wilting-induced increase in ACC and ethylene synthesis.