Figure 1

Confocal microscopic analysis of SEP3:GFP localisation in inflorescence meristem and early flower bud stages. (A) Overview of an inflorescence with the inflorescence meristem and early flower bud stages 1 to 5 indicated. SEP3:GFP protein is detected as green signal and cell membranes are stained with the red dye FM4-64. (B) Detail of an inflorescence meristem and a stage 2 flower bud. (C) Section through tissue in (B) showing the SEP3:GFP signal in the epidermis and the beginning SEP3:GFP signal in the centre of the stage 2 flower bud. (D) Detail of a stage 4 flower bud showing the highest SEP3:GFP signal in the entire floral meristem and only in the epidermis of the four sepals. (E) Section through the stage 4 flower bud in (D) showing both cytoplasmic and nuclear localisation of SEP3:GFP in the future second and third whorl, and only nuclear localisation in the innermost part of the floral meristem. (F) More basal section through the stage 4 flower bud in (D) showing again both cytoplasmic and nuclear localisation of SEP3:GFP in the future second and third whorl. (G) Detail of a stage 5 flower bud showing the initiating petal and stamen primordia. (H) Section through the stage 5 flower bud in (G) illustrating that the SEP3:GFP signal in whorl 4 is mostly nuclear, while the reduced signal in the initiating petal and stamen primordia is both cytoplasmically and nuclear localised. (I) More basal section through the stage 5 flower bud in (G) showing the SEP3:GFP signal at the adaxial and abaxial sides of a sepal. (1–5) flower bud stages; (ab) abaxial; (ad) adaxial; (FM) floral meristem; (IM) inflorescence meristem; (i) innermost part floral meristem; (L1) epidermal cell layer; (L3) inner cell layers; (p) petal; (s) sepal; (st) stamen; (w4) whorl 4. Scale bars of (A) 50 μm and of (B-I) 25 μm.