Soluble and lamellar proteins in seedlings of barley and its virescens mutant in relation to chloroplast development

Abstract

When Gateway barley and its mutant were grown at 600 ft-c and 20 °C the soluble leaf proteins separated into 21 discrete bands by acrylamide gel electrophoresis. The most intense broad band of low mobility probably was fraction I protein and was present in 4-, 6-, and 8-day-old seedlings. At 4 days the amount of this protein in the mutant was small but it increased with age. At 8 days no differences were observed in the electrophoretic patterns of the two lines.On treatment of chloroplast lamellae with 0.5% sodium dodecyl sulfate several proteins were separated electrophoretically from Gateway barley at 4, 6, and 8 days. When grown at 600 ft-c and 20 °C, 4-day-old seedlings of the mutant lacked some of the proteins but at 8 days the gel patterns of Gateway and its mutant were similar. When grown at 1400 ft-c and 23 °C the mutant compared to Gateway lacked some proteins even at 8 days.Under 600 ft-c and 20 °C the mutant had about one-third as much chlorophyll as the normal at 8 days and under 1400 ft-c and 23 °C it had only about one-fifth as much. Electron microscope studies of the leaves showed that Gateway barley had well-developed chloroplasts under both growth conditions at 4 days, whereas the plastids of the mutant were not well developed at 4 or 6 days. By 8 days under the lower light intensity the mutant contained normal plastids but under the higher intensity the plastids were still not well developed. A relationship between chloroplast morphology and the proteins and pigments present was noted.