Blue light-dependent, random hypocotyl-bending is observed only in the +cry1, +cry1T, +cry2, and +cry2T mutants. Seedlings of wild type, the quadruple mutant, and the +cry1, +cry1T, +cry2, +cry2T, +phot1, +phot1T, +phot2, and +phot2T mutants were grown in the dark or under blue light irradiation for 3 days. The degree of deviation of hypocotyl growth from phototropic vector was measured.