Changes in Phytohormone Contents in Chickpea Seeds Germinating Under Lead or Zinc Stress

Abstract

The present work describes the changes that take place in phytohormone contents in germinating chickpea (Cicer arietinum cv. Aziziye-94) seeds in response to heavy metal stress. For this aim, endogenous abscisic acid (ABA), gibberellic acid (GA(3)), zeatin (Z) and zeatin riboside (ZR) contents were followed for 24, 48 and 72 h in chickpea seeds germinating at the concentrations of 0.1, 1.0 and 5.0 mM Pb or 0.1, 1.0 and 10 mM Zn. The results showed that Pb and Zn significantly delayed and impeded the germination of chickpea seeds. The negative effect of Pb on germination was higher than that of Zn. Further, Pb increased ABA and Z contents while decreased GA(3) content in the germinating seeds. The high concentrations of Zn (1.0 and 10 mM) decreased contents of Z, ZR and GA(3) while 0.1 mM Zn increased the content of the same hormones. The ABA content was enhanced by Zn in all concentrations used.