Figure 7.

CBL4, CIPK26, and OST1 are required for systemic cell-to-cell ROS signaling and acclimation to light stress. A, Representative time-lapse images of whole-plant ROS accumulation in WT and cbl4-1 plants subjected to a local HL stress treatment (applied to a single local leaf; indicated with a circle) are shown alongside bar graphs of combined data from all plants used for the analysis at the 0- and 30-min time points (local and systemic). B, Same as (A), but for WT and cipk26-2 plants. C, Same as (A), but for WT and ost1-2 plants. D, Averaged measurements of leaf injury (increase in ion leakage) in WT, cbl4, cipk26, and ost1 plants. Measurements are shown for unstressed plants (control), local leaves subjected to a pretreatment of HL stress before a long HL stress period (local acclimation), systemic leaves of plants subjected to a local HL stress pretreatment before a long period of local HL stress was applied to a systemic leaf (systemic acclimation), and systemic leaves of plants subjected to a long HL stress period without pretreatment (HL without pretreatment). All experiments were repeated at least three times with 10 plants of each genotype per experiment. ROS accumulation was imaged using H₂DCFDA. Data are presented in (A) to (C) as box plot graphs; X is mean ± se, N = 30, **P < 0.01, Student t test. Data are presented in (D) as box plot graphs; X is mean ± se, N = 30, one-way ANOVA followed by a Tukey test; lowercase letters donate significance (P < 0.05). Scale bar, 1 cm.