SPECTROPHOTOMETRIC AND IMMUNOBLOT ANALYSES OF PHYTOCHROME IN D(-) AND D(+) RICE SEEDLINGS (ORYZA-SATIVA L)

Rice seedlings exhibit dimorphism in the dark and light when germinated in oxygen deficient and oxygen sufficient environments. Seedlings germinated in the dark and light under oxygen deficiency only exhibit white coleoptile growth, d(-) type of development. In oxygen sufficient environments, dark-germinated seedlings develop into normal etiolated plants, d(+) type of development, whereas light-germinated seedlings develop into normal green plants. The white coleoptiles of both dark- and light-germinated d(-) seedlings examined spectrophotometrically do not exhibit red/far red photoreversibility, do not possess protochlorophyllide in the dark or light and do not possess chlorophyll in the light. Spectrophotometry shows that the shoots of the dark-germinated etiolated d(+) seedlings exhibit normal red/far red photoreversibility and contain protochlorophyllide. Chlorophyll is present in the normal light-germinated green seedlings. Immunoblot analyses show marked differences between phytochrome protein isolated from the coleoptiles of the dark- and light-germinated d(-) seedlings and that isolated from the shoots of the dark-germinated normal etiolated d(+) seedlings. Thus, molecular oxygen and normal oxidative metabolism are essential for both normal morphogenetic development in the dark and normal photomorphogenetic development in the light of germinating