Fig. 1. drn mutant and drn drnl double-mutant phenotypes. Wildtype embryos at early (A) and late (B) globular stages. Abnormal hypophyseal cell divisions in drn-1 mutant embryos at early (C) and late (D) globular stages. (E) Multiple cell files in the suspensor of a drn1 mutant; the embryo proper is towards the top. (F) drn-1 mutants lacking basal embryo organisation. (G-K) Pleiotropy of cotyledon phenotypes for the drn-1 mutant showing mono-(G) and polycotyledony (I), cotyledon fusion (H) and cup-shaped cotyledons (J). The SAM is active despite complete cotyledon fusion (K). (L,M) mp-like phenotype of drn (L) and drn-1 drnl-1 (M) mutants. (N,O) Altered phyllotaxis of first leaves in monocotyledonous (N) or polycotyledonous (O) drn-1 mutants. (P-R) Cleared cotyledons of wild type (P) and a monocotyledonous drn-1 mutant showing single (Q) or fused cotyledon (R) ontogeny. (S,T) drn-1 drnl-1 double-mutant embryos showing asymmetric cell divisions at early (S) or late (T) globular stages. (U,V) pin-like hypocotyl of drn-1 drnl-2 double-mutant plant lacking cotyledons (U) and directly producing leaves as evidenced by trichome formation (V).