Determination of seed germination
Seeds of cucumber (Cucumis sativus L., cv Zhongnong 8)
were surface-sterilized for 15 min in 10% (v/v) sodium
hypochlorite solution, and rinsed thoroughly with deionized
water. Seeds were then used to investigate the effect of
24-Epibrassinolide and ethylene on seed germination in the
presence of NaCl. Cucumber seeds were placed randomly
in Petri dishes (9.0 cm diameter) containing filter paper
soaked with 5 ml treatment solution at 28C for 48 h in a
growth chamber in the dark. There were 40 seeds in each
Petri dish and seeds were considered to be germinated at
the emergence of the radicle and scored. The effects of
24-Epibrassinolide and ethylene on seed germination in the
absence and presence of 250 mM NaCl were investigated
by treating the seeds with solutions containing 0.5 mM
CaCl2 with varying concentrations of 24-Epibrassinolide,
ethylene synthesis precursor (1-aminocyclopropane-1-carboxylic
acid, ACC), antagonists of ethylene (aminoethoxyvinylglycine,
AVG and CoCl2). 24-Epibrassinolide
stock solution was prepared by dissolving the chemical in
ethanol, and the same amount of ethanol was added in the
control solution. All other compounds were freshly prepared
as stock solutions in sterilized deionized water for
each experiment, and diluted to the appropriate concentrations
just before use