Figure 6. Delayed leaf senescence in GA-deficient and GA-insensitive poplar transgenics during SD-induced transition to bud dormancy.

Two representative leaves are shown for comparison. Measurements represent computer based quantification of the relative intensity of green color in senescing leaves (see Material and Methods). Plants were grown for nine weeks under SD photoperiod (8 h). The temperature was maintained at 21°C for the first six weeks and reduced to 4°C for the remaining three weeks. Significant differences between transgenic and WT treatments were determined by one-way ANOVA followed by Dunnett’s post-hoc test (*, P<0.05).