Stimulation of glycolysis in anaerobic elongation of pondweed (Potamogeton distinctus) turions.
Stem segments prepared from pondweed (Potamo geton distinctus A. Benn.) turions (overwintering buds) elongate in anaerobic conditions, whereas there is almost no elongation in air. The anaerobic elongation was accompanied by a decrease in dry weights of stem segments, mainly due to consumption of storage starch in the amyloplasts of stem cells. On the other hand, total contents of amino acids increased in stem segments, in which contents of alanine, valine, leucine, and isoleucine increased, but contents of asparatic acid decreased. Moreover, contents of lactate in stem tissues increased at an early stage of anaerobic incubation. In tracer experiments with 14C-glucose, 14C incorporation into stem tissues in anoxia was only half of that in normoxia. However, conversion of 14C to ethanol occurred exclusively in anoxia. 14C-labelled metabolites were analysed by two-dimensional cellulose thin-layer chromatography. 14C incorporation into sucrose and alanine was significantly increased in anoxia. The activity of alanine aminotransferase was enhanced by anoxia, suggesting that pyruvate is a precursor of alanine synthesis. The results suggest that pondweed turions produce energy necessary for anaerobic elongation by activating conversion of storage starch in the amyloplasts to ethanol, alanine and lactate.
Sato
Tatsuhisa
T
Department of Developmental Biology and Neuroscience, Graduate School of Life Sciences, Tohoku University, 980-8578 Sendai, Japan.
Harada
Taro
T
Ishizawa
Kimiharu
K
D000332:Aerobiosis / Q000502:physiology; D000410:Alanine Transaminase / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism; D000693:Anaerobiosis / Q000502:physiology; D050260:Carbohydrate Metabolism; D002250:Carbon Radioisotopes; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D006019:Glycolysis / Q000187:drug effects* / Q000502:physiology; D019344:Lactic Acid / Q000378:metabolism; D019684:Magnoliopsida / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism / Q000494:pharmacology; D010100:Oxygen / Q000378:metabolism / Q000494:pharmacology*; D018547:Plant Stems / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D018087:Plastids / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism; D019289:Pyruvic Acid / Q000378:metabolism / Q000494:pharmacology; D013213:Starch / Q000378:metabolism
D000596:Amino Acids; D002250:Carbon Radioisotopes; D011134:Polysaccharides; D019344:Lactic Acid; D019289:Pyruvic Acid; D013213:Starch; D000410:Alanine Transaminase; D005947:Glucose; D009584:Nitrogen; D010100:Oxygen