SYNTHESIS OF MACROMOLECULES IN MAIZE ROOT TIPS

Publisher Website
Google Scholar
Abstract
Corn roots grown in a glucose–salts medium in a continuous flow system suffered an initial loss of protein before an increase was observed. A maximal rate of increase in cell-wall carbohydrates was achieved after 20 hours in culture. There was some loss in RNA while the increase in DNA was slight. A synthetic mixture of 15 L-amino acids enhanced the growth (defined as increase in length, dry weight, or alcohol-insoluble nitrogen) of glucose-grown roots. With this enriched medium there was a slight increase of protein over the initial 20-hour period and a faster rate of increase after this time. No lag in the increase in cell-wall carbohydrates was observed. Despite these symptoms of better growth the level of DNA was not improved by the addition of the amino acids and the RNA content was actually lower than in the glucose-grown roots. Although the level of RNA was less in cultured than in normal roots, ribosomal and soluble RNA accounted for similar proportions of the total RNA in each case.