FIGURE 12.
Effect of cytokinin preincubation on freezing tolerance of arr5, arr6, arr7 single mutants and Pro35S:ARR7 lines compared with the wild-type plants. A, arr5, arr6, and arr7 mutants preincubated with or without cytokinin for 7 days. Experiments were conducted and analyzed as described in Fig. 11, C and D. B, example plates showing the arr5, arr6, arr7 mutants, and the wild-type (Col-0) plants preincubated with or without cytokinin for 7 days, subjected to freezing treatment (A). C, Pro35S:ARR7 lines compared with the arr7 mutants and Col-0 and Pro35S:GUS control plants preincubated with or without cytokinin for 7 days. Experiments were conducted and analyzed as described in A except that the plants were treated at −5 °C for 8 h for freezing. Numbers 4-11 and 23-1 indicate the line number of Pro35S:ARR7 transgenic plants. * denotes statistically significant change with p < 0.05 compared with arr7 and control plants pretreated with cytokinin. D, example plates showing Pro35S:ARR7 lines, the arr7 mutants, Col-0, and Pro35S:GUS control plants preincubated with or without cytokinin for 7 days and then subjected to freezing treatment (C).