Rates of germination of wild-type and ΔgerD spores. Wild-type (PS832) and ΔgerD (FB62) spores were germinated with either l-alanine or AGFK, and germination was assessed by measuring DPA release as described in Materials and Methods. ○, wild-type spores with l-alanine; ▵, wild-type spores with AGFK; ▴, ΔgerD spores with l-alanine; •, ΔgerD spores with AGFK.