This paper studies the relative importance of endogenous ABA and ion toxicity in the leaf growth inhibition caused by NaCl in salt-adapted and unadapted bush beans. Adaptation to salt-stress was achieved by germination of seeds in 75 mM NaCl, while unadapted plants were germinated in tap water. The adaptation process caused a transitory increase in leaf ABA, Na+ and Cl- concentrations, while leaf expansion was inhibited. However, when grown for 8 or 13 days in 75 mM NaCl-containing nutrient solution, primary and first trifoliolate leaves of salt-adapted plants had greater areas than those of unadapted plants. Concentrations of ABA, Na+ and Cl- in these leaves were lower in adapted plants, and a strong negative correlation between leaf expansion growth and either leaf Na+, Cl- or ABA concentrations could be established. However, in the second trifoliolate leaves only the ABA, but not the Na+ or Cl-, concentrations were significantly correlated with leaf expansion. Our results suggest that salt-induced inhibition of leaf expansion growth in bush beans is mediated by ABA rather than Na+ or Cl- toxicity. Moreover, the increase of ABA, induced by the salt-pretreatment, seems to play an important role in limiting the accumulation of Na+ and Cl- in the leaves, leading to adaptation of bush beans to salt-stress.
|Publication status||Published - 1 Dec 1997|
- Abscisic acid
- Bush beans
- Phaseolus vulgaris