Figure 6.
Galactosyltransferase activity in response to Pi starvation. Enzymatic reaction was performed using radiolabeled UDP-Gal as a substrate in crude extracts from several samples. A, Radioactivity incorporated into lipids was visualized by Image Analyzer (Amersham Bioscience, Piscataway, NJ). Lanes 1 to 4, Enzymatic activity in the shoot of Pi-replete plants, the shoot of Pi-depleted plants, the root of Pi-replete plants, and the root of Pi-depleted plants, respectively. SG, Sterylglycoside, Gcer, glycosylceramide. B, Relative values of radioactivity incorporated into galactolipids. White bars indicate the activity detected in Pi-replete plants. Gray bars indicate the activity measured in Pi-depleted plants. Radioactivity of MGDG in the shoot of Pi-replete plants corresponds to 100%. Presented values are means from five independent measurements (±se).