Effects of Ca2+ on the Expression Levels of ACS gene CsACS1 (A), CsACS2 (B), CsACS3 (C), and ACO gene CsACO1 (D), CsACO2 (E) in cucumber explant under salt stress at 48 h. The primary roots were removed from hypocotyl of 5-day-old seedlings. Explants were incubated for five days with distilled water as control, meanwhile the explants were incubated with 13 mM NaCl after being treated with distilled water or 10 μM CaCl2, 500 μM LaCl3, 100 μM EGTA, 500 μM LaCl3 + 10 μM CaCl2, and 100 μM EGTA + 10 μM CaCl2, respectively. The values (means ± SE) are the average of three independent experiments. Bars with different lowercase letters were significantly different by Duncan’s multiple range test (P < 0.05).