Figure 6.

GA Abundance Modulates Root Elongation in Seedlings after Cold Stress in a GRF-Dependent Manner.

(A) Representative images of wild-type seedlings (Col) and of seedlings of transgenic lines overexpressing GRF5 (35S:GRF5), which is not targeted by miRNA396, or the GRF-targeting miRNA396b (35S:miR396b). Seedlings were germinated for 6 d on half strenth MS (without mock or hormone treatment) at ambient temperature. Seedlings were then transferred for 7 d to half strenth MS containing 10 µM GA3 (GA) or 0.1 µM PAC (PAC) or a corresponding mock solution for 7 d at 21°C. In a parallel setup, the seedlings were first exposed to a 7-d 4°C cold stress treatment, which fully arrests plant growth, followed by a 7-d recovery period at 21°C.

(B) Scatterplots of individual measurements (dots) of root elongation measurements of seedlings shown in (A). The dotted lines mark the means of the mock-treated wild-type sample and serve for orientation. Data sets with no statistical difference after ANOVA and Tukey’s HSD posthoc test fall into one group and are labeled with identical letters.