GUS expression under the control of the SAG12 gene promoter during unfertilised pistil development in ethylene signalling mutants. (A) GUS histochemical assay in unfertilised pistils of the SAG12:GUS line reveals onset of ovule senescence at 2 DPA, and that senescence progressed acropetally over the next two days. (B and C) GUS histochemical assay in the unfertilised pistils of the SAG12:GUS line in (B) ein2-5, and (C) ctr1-1. The onset of ovule senescence is delayed by 1 day in ein2-5 and is advanced by 1 day in ctr1-1. Senescence progression follows a similar kinetics as in the wild-type plant (A). Plants were in the cer6-2 background.