|Budget Amount *help
¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1994 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1993 : ¥1,600,000 (Direct Cost : ¥1,600,000)
In order to dissect a transduction chain which originates from a photoreceptor, phytochrome A,we have screened Arabidopsis mutants which are more sensitive to continuous far-red light irradiation with respect to elongation and accumulation of anthocyanin in hypocotyl tissue. We obtained 7 such mutants so far. They are all recessive, and consist of at least 3 complementation proups. All of them show a shorter hypocotyl in darkness and a shorter inflorescence stem under white light than wild type. The growth inhibition is not specific to farred light, but is also observed under red and blue light. One of them shows high accumulation of the pigment but the growth inhibition is relatively small. Thus, it may be considered as a high-pigment mutant already reported in tomato plants (Peters et al., 1989). These mutants were not included in the T-DNA tagged lines available from Arabidopsis Stock Center at Columbus.
We also found that an addition of sugar partially rescued growth defection observed in hypocotyl of the fhy3 mutant which lacks a component in the transduction chain of phytochrome A (Whitelam et al., 1993). This indicates that the transduction chain consists of two parallel pathways, and that one of them is controlled by sugar as well as phytochrome A.