Figure 7.

sta-1 Is Altered in Its Sensitivity to ABA.

(A) sta-1 shows hypersensitivity to ABA for seed germination. In this assay the number of seeds germinated was analyzed at 24 h after removal from 4°C, a time point where the maximum number of seeds have germinated in each line. The data points are presented as the percentage of seeds germinated relative to germination in the absence of ABA. Two hundred seeds are analyzed per treatment.

(B) to (E) In contrast with seed germination, sta-1 is insensitive to ABA for lateral root initiation (B) and induction of RD22 (C) as well as stomatal closure ([D] and [E]). In (D) and (E), the plants were pretreated to ensure maximal stomatal opening and then secondarily treated with buffer alone (0) or with buffer containing 25 μM ABA. In wild-type plants, all stomata closed in the ABA treatment, while in sta-1 mutant leaves, all stomata remained open.