Figure 7. ABA and stress responses of ibr5 alleles.

a) inhibition of primary root elongation by ABA. Four day old seedlings were transferred on to ATS containing 10 µM ABA, and the length of the primary root was measured after 4 day incubation at 21°C under continuous illumination. Error bars indicate standard error of the mean (n = 15). Stars indicate that the means differ significantly from the control, letters indicate the samples that differ significantly from each other (ANOVA, Tukey's HSD, P<0.05). b) Post germination inhibition by ABA and stresses. Seeds stratified at 4°C for two days were grown on media containing indicated amounts of ABA, NaCl or mannitol. Seedlings with green cotyledons were counted after 7 days of growth, and percentage was calculated. c–d) Expression of IBR5::IBR5.1-GUS in response to ABA and stresses. Four day old IBR5::IBR5.1-GUS transgenic seedlings treated with various concentrations of ABA, NaCl or mannitol for 18 hrs were used to perform quantitative GUS assays. Each data point indicates the mean value of 3 replicates. e–f) Expression of IBR5 in response to ABA and stresses. Four day old Col-0 seedlings treated with various concentrations of ABA, NaCl and mannitol for 18 hrs were used. Expression of IBR5 was assessed by qRT-PCR. UBA (AT1G04850) was used as the internal control. g) Response of ibr5 alleles to oxidative stress in post germination growth. The experiment was performed as described in (b) in the presence of 1 µM methyl viologen. Seedlings with green cotyledons were counted after 7 days of growth, and percentage was calculated. Error bars indicate standard deviation from the mean. Stars or letters indicate that the means differ significantly from the respective control (ANOVA, P<0.05).