Protein Synthesis During Water Uptake by Tuber Tissue

Publisher Website
Google Scholar
Abstract
Synthesis of protein (trichloracetic acid insoluble nitrogen) and metabolic uptake of water have been followed simultaneously in slices of potato and artichoke tuber. In freshly-cut potato slices a small amount of heat-coagulable nitrogen escapes precipitation with TCA. This fraction, which may consist of polypeptides, disappears after 2 to 4 days of water uptake. Protein is rapidly synthesized in potato slices during the first 2 days after equilibration, when water uptake is small. It tapers off in the next 2 to 4 days while water uptake greatly increases. Artichoke shows similar behavior, with the difference that during the second 2-day period synthesis gives way to a net hydrolysis. In both tissues naphthalene-acetic acid markedly increases protein synthesis in the first two days. The magnitude of the increase is roughly commensurate with that of the increase in water uptake, being about 15% in potato slices but 400% in artichoke. Five experiments with potato showed that the naphthalene-acetic acid effect, though small, is reproducible. It is suggested that the proteins synthesized include enzymes, and that this phenomenon may explain the frequently observed increase in enzyme activity following auxin treatment.