Determinazione “Invivo“ Dell'attività Deidrogenasica Mediante la Tecnica al Tetrazolio

Abstract
The adaptability of the tetrazolium reaction for the determination of the activity of dehydrogenasic systems «in vivo», in free cells, tissue slices and isolated plant parts has been investigated. In experiments on Helianthus tuber disks it has been found that only for high concentrations (1,5%) of triphenyl tetrazolium chloride (TTC) in the medium, a concentration of the reagent high enough to saturate the reducing systems in the cell penetrates the tissue. At concentrations of TTC higher than 2% the rate of the reaction decreased. The most convenable value of pH for the reaction «in vivo» appeared to be slightly above neutrality. Oxygen was found to compete efficiently with TTC for the hydrogen freed from respiratory substrates by dehydrogenase action. TTC reduction in tuber disks kept in vacuum for the period of the reaction, or put into solutions previously deaereated, was by far more intense than in the controls, kept in not deaereated solutions. These results appeared fully confirmed by other experiments, run on the most various materials.