Influence of jasmonic acid on endogenous gibberellin and abscisic acid in salt-stressed chard plant.

The endogenous gibberellin (GA) and abscisic acid (ABA) contents as an effect of different application times of jasmonic acid (JA) in chard seedlings exposed to salt stress were investigated. Endogenous ABA content was increased by JA treatment after NaCl treatment, rather than after JA application before NaCl treatment. JA application after NaCl treatment caused higher ABA content than treatment with 160 mM NaCl alone. Total gibberellin content decreased after NaCl stress, but NaCl-reduction in total GA contents counteracted by exogenous JA. Total endogenous GA contents were increased in JA treatment after NaCl and were highest at 24 hr of JA application before NaCl exposure. JA treatment promoted the increase of dry weight compared to chard plant exposed to 160 mM NaCl. Thus, JA presumably induces gibberellin biosynthesis showing the promotion of growth and dry weight of chard plants under salt stress.