Figure 1.

Phenotypic comparison of the BR biosynthetic mutant dwf4-1, and the insensitive mutants bri1-5, twisted1-60, and dwf12. Plants shown are 25 d old. dwf12 exhibits characteristic BR dwarf phenotypes including short inflorescences, infertility of homozygous mutants, short round leaves, and abnormal de-etiolation. In addition, dwf12 leaves show more severe downward curling than dwf4 and bri1. This phenotype and the mild twisting of inflorescences appear to be weaker version of twd1 (B. Schulz and K. Feldmann, unpublished data). The height of dwf12 heterozygous plants is intermediate between the homozygote and wild type, suggesting that the mutation is semidominant. Unit bar = 2 cm. In the inset, one set each of the adaxial side of a cauline leaf, a rosette leaf, and a silique of Ws-2 wild type, dwf12-1D, dwf12-2D, dwf12-1D/+, and dwf12-2D/+ are shown. Note the extreme downward curling of the leaves. Siliques of the homozygous dwf12 mutants are almost completely sterile and contain few seeds.