Activation of phosphate metabolism in cotyledons of Pharbitis nil in the early stage of germination as studied by multicompartmental analyis

A new computation method has been introduced into multicompartmentalanalysis, which saves computer time and gives good fitting parameterseven in complicated systems. This method was applied to theanalysis of phosphate metabolism in the cotyledons of Pharbitisnil during the early stage of germination. Soon after the startof imbibition, the metabolic flows of phosphate were initiatedby very small amounts of enzymes. Some enzymes involved in phosphorylation,RNA synthesis, and phospholipid synthesis were indicated asexisting in the seeds and as being activated from nonactiveforms during imbition. The activities of all phosphate metabolisms,except the breakdown of RNA, phospholipids and protein-boundphosphates, were activated about ten to hundred-fold after thestart of protein synthesis. The technique of multicompartmental analysis can be appliedto various physiological problems to estimate the quantitativeand systematic metabolic flows in any tissue. (Received July 5, 1973; )