Fig. 2. hap2 blocks egg fertilization and central cell fertilization. Siliques from self-fertilized plants heterozygous for a control T-DNA insertion (A) or hap2/HAP2, which contain aborted ovules (B, arrowheads). (C) An unfertilized ovule showing nuclei of FG cells. (D-I) Ovules following targeting by HAP2 (D,E,I) or hap2 (F,G,H) pollen tubes at either 48 (D-G) or 24 hours (H,I) after pollination. Early embryo and endosperm development are apparent in ovules targeted by HAP2 (D,E,I), but not hap2 (F,G,H) pollen tubes. Ovules stained for GUS activity (D,F) show that they have been targeted by either HAP2 (D, no GUS activity) or hap2 (F, GUS activity present in synergid) pollen tubes and that hap2 pollen tubes have burst in the targeted ovule. ccn, central cell nucleus; ecn, egg cell nucleus; scn, synergid cell nucleus; emb, embryo; arrowheads, endosperm nuclei. Arrows (C,F,G,H) denote an unfertilized central cell. Scale bars: 20 µm.