Inheritance and characterization of a dark-germinating, light-inhibited mutant in the fern Ceratopteris richardii

Abstract

Selection for a dark-germinating mutant was made with X-irradiated spores of Ceratopteris richardii. A single mutant line (HαDG1) was recovered and analyzed for its germination responses under different light–dark treatments and for transmission of the trait through a complete sexual cycle. HαDG1 was characterized by two phenotypes, dark germination and light inhibition of germination. These responses were exactly opposite from wild-type responses. The level of dark germination for a particular spore batch was stable through time, whereas light inhibition was unstable with time. Genetic analysis indicated that both phenotypes are associated with a single nuclear gene mutation that has been designated dkg1. Key words: fern, photomorphogenesis, mutant selection, germination, spore.