Fig. 5. Consequences of overexpression and ectopic expression of PTL. (A) ptl-1 mutant inflorescence. (B) Complementation of ptl-1 mutant phenotype in pPTL(1.3i)>>PTL plant (moderate driver line #5). (C) Gain-of-function phenotype in pPTL(1.3i)>>PTL ptl-1 plant (strong driver line #7). Lateral sepals are absent, and four petals are restored, either separate (SEM inset), or fused along their lateral margins. (D,E) SEMs of inflorescence apex of (D) wild-type plant and (E) gain-of-function pPTL(1.3i)>>PTL ptl-1 plant (strong driver line #1). Buds at stages 4, 5 and 6 are indicated. Lateral sepals are either absent or narrow in gain-of-function plants (E, arrows). (F) SEM of pAP1>>PTL plant with inflorescences producing flowers arrested at stage 2. (G) pAP3>>PTL flower showing absence of petals and stamens, and reduced lateral sepal. (H) SEM of pAP3>>PTL flower showing absence of petal and stamen primordia in the second and third whorls. ca, carpel; f, filamentous structure; se, sepal. (I) p35S>>PTL seedling showing final extent of growth. Strongly inducible PTL target line #10 was used for all ectopic expression plants (F-I). Scale bars: A-C,G, 1 mm; inset in C, D-F,H,I, 100 µm.