Indoleacetic acid, gibberellic acid, zeatin, and abscisic acid levels in NaCl-treated tomato species differing in salt tolerance

Abstract

Indoleacetic acid (IAA), gibberellic acid (GA₃), zeatin, and abscisic acid (ABA) levels in cultivated tomato Lycopersicon esculentum (Mill.) cultivar Falcon 82 and its wild salt-tolerant relative L. pennellii (Correll) were examined over a range of 0 to 150 mM NaCl applied for 72 h. The treatment with 50 mM and 150 mM NaCl reduced relative water and protein contents in L. esculentum, but did not affect relative water content and increased protein content in L pennellii. Varietal differences between L. esculentum and L. pennellii were also observed in hormonal contents during the stress period. ABA levels in treated plants of both species increased significantly compared to the controls. However, the increase in the leaves of L. pennellii due to NaCl stress was not as pronounced as that of L. esculentum; it was significantly higher (p < 0.05) than that of salt-sensitive L. esculentum. In treated plants, zeatin concentrations in the leaves of L. esculentum decreased within 24-72 h after treatment. Nevertheless, L. pennellii responded to all the NaCl levels used by increasing zeatin concentrations after short-term, 72-h NaCl stress.