Changes in the Polyadenylated RNA from Wolffia arrhiza Continuously Illuminated with White, Blue or Red Light

Abstract

Summary Polyadenylated RNA was isolated from Wolffia arrhiza (L.) WIMM. The plants were cultivated under steady state conditions in a chemostat and continuously illuminated with white, blue or red light (photon fluence rate: 15 µmol m-2 s-1, growth rate µ = 0.006 or 0.012 h-1, limitation by 2.3 mg Pl-1). The poly(A) RNA, e.g., from a sample of total RNA (132.4 µg g fresh weight-1) amounted to 6.6 µg g fresh weight-1 (µ = 0.012 h-1, continuous white light). The level of poly(A) RNA (expressed as percent of total RNA) is affected by light quality: Intact plants show an increase in the succession red light, blue light, white light, and in isolated chloroplasts in the succession red or blue light and white light. On the other hand, in intact plants as well as in isolated chloroplasts the amounts of polyadenylated RNA are independent on the growth rate. After transition of plants from white or blue light to darkness the content of poly(A) RNA decreases to a low level, and after transition from red light to darkness the polyadenylated RNA disappeared. [5-3H]-uridine incorporation into total RNA is influenced by the wavelength of light as well as the growth tate, e.g., the ratio “radioactivity incorporated/radioactivity taken up” decreases in the succession white light, blue light, red light. Using plants illuminated continuously with white, blue or red light [5-3H]uridine incorporation into poly(A) RNA was inhibited completely by ∝-amanitin.