Effect of BR and ACC on seed germination To test whether BRs and ethylene play a role in germination
of cucumber seeds suffering from salt stress, the dose response of seed germination to BR and ethylene precursor
ACC in the presence of NaCl was investigated.
As shown in Fig.
1a, the cucumber seeds used in the present study had an average germination rate of 97% after 48 h imbibition
in control solutions, and the germination was reduced to about 20% when 250 mM NaCl was present in
the incubation medium.
The inhibitory effect of NaCl on seed germination was significantly ameliorated by addition of EBR into the incubation medium with the optimal concentration being 5 lM EBR.
Given that 5 lM EBR was optimal in terms of its effect on seed germination under conditions of salt stress, this concentration was used to study the role of BR in seed germination under salt stress throughout the study.
Similar to EBR, the reduction in seed germination induced by NaCl was also alleviated when ACC at concentrations greater than 1 lM was present in the incubation medium, and the ameliorative effect of ACC on seed germination in the presence of NaCl was positively dependent on ACC concentrations (Fig. 1b).
Furthermore, the alleviative effect of EBR and ACC on seed germination in the presence of NaCl exhibited additive effect such that seed germination rate was greater in the presence of EBR and ACC together than in the presence of EBR and ACC alone in the incubation medium under conditions of salt stress