Fig. 7.

Phenotypes of the overexpression and RNAi lines of GUN4 gene. a Test of the expression levels of GUN4 gene in the transgenic lines by real-time PCR analysis. Col, wild-type Col-0 plants; GOE3 and GOE9, GUN4-overexpression lines 3 and 9, respectively; RG4, RG10, RG12, RG13 and RG15, GUN4-RNAi lines 4, 10, 12, 13 and 15, respectively. b Seed germination rate of the wild-type plants (Col) and different transgenic lines as described in (a) in the ABA-free medium (0 μM ABA) and ABA-containing medium (0.5, 1 and 2 μM) 60 h after stratification. Each value is the mean ± SE of five independent biological determinations and different letters indicate significant differences at P < 0.05 (Duncan’s multiple range test) when comparing values within the same ABA concentration. c and d, Early seedling growth of the wild-type plants (Col), different GUN4-RNAi lines (c) and two GUN4-overexpression lines (d) in the ABA-free medium (0 μM ABA) and ABA-containing medium (0.8 μM) 12 d after stratification. The experiments were repeated independently five times with the same results. (e) and (f), ABA-induced stomatal closure (top panel) and ABA-inhibited stomatal opening (bottom panel) for wild-type Col and different GUN4-RNAi lines (e) and two GUN4-overexpression lines (f) in the ABA-free medium (0 μM ABA) and ABA-containing medium (20 μM). Values are the mean ± SE from three independent experiments and different letters indicate significant differences at P < 0.05 (Duncan’s multiple range test) when comparing values within the same ABA concentration. n = 60 apertures per experiment