Figure 3.

OH^•-Activated [Ca²⁺]_cyt Increase in Root Epidermal Protoplasts Is Impaired in ann1.

(A) Root epidermal protoplast [Ca²⁺]_cyt was measured with cytosolic aequorin. Control touch response (buffer only at 35 s) was similar in the wild type (WT) and ann1. OH^• was generated by 0.5 mM Cu-Asc. Data are mean ± se (n = 4). Buffer comprised 10 mM CaCl₂, 0.1 mM KCl, and 2 mM Tris/MES, pH 5.8, adjusted to 270 mOsM with d-sorbitol.

(B) As in (A) but protoplasts were incubated with 300 μM GdCl₃ for 30 min prior to [Ca²⁺]_cyt measurement (n = 3).

(C) Summary plot of experiments from (A) and (B) showing the effect of Gd³⁺ on OH^•-induced [Ca²⁺]_cyt responses of wild-type and ann1 protoplasts.