XVI International Botanical Congess

In fern gametophytes, various red/farred light-mediated responses areobserved. To study the mechanisms of these responses, we cloned phytochrome genes and isolated photomorphogenic mutants from Adiantum capillus-veneris. Three of four phytochrome genes have been sequenced. PHY1, two are ordinary phytochrome, but PHY3 is chimeric with phytochrome chromophore binding domain in N-terminus and NPH1-related sequence in C-terminus, suggesting that PHY3 absorbs red/farred as well as blue light. Aphototropic mutants (rap) do not show phototropism of protonemata under red light. The mutants are also defective in the red light-mediated chloroplast movement, but normal in the blue light-induced chloroplast movement. We will discuss on the PHY3 function in this mutant.