| Abstract: | A method suitable for the study of the physiology of absorptionof substances from solution and of respiration of Peltigerapolydactyla was elaborated making use of discs of tissue whichcould be floated on solutions. The rate of absorption of hexosesugars by the discs was sensitive to temperature, the presenceof inhibitors, such as sodium fluoride and silver nitrate, butrelatively insensitive to hydrogen ion concentration. Glucosewas absorbed preferentially to fructose from equimolar solutions.Absorption of sugar from sucrose solutions involved inversionby an enzyme system held on the cell surface. This system wasrelatively unaffected by exposure to moderate temperature, tosodium fluoride or silver nitrate but sensitive to hydrogenion concentration. Sucrose did not seem to be absorbed as suchand the glucose was absorbed preferentially from the productsof inversion. All parts of the thallus were equally effectivein inversion but absorption was mainly into the algal layer.The entry into the tissues was associated with a respiratoryrise. |
