Potato tubers respiration rate

In recent years a number of in vitro experiments have been reported on a variety of plant materials—segments of oat coleoptiles, segments of barley root, cut-up spinach leaves, discs of rhubarb leaves, slices of potato tubers —which demonstrate the utilization of di-and tricarboxylic acids by respiring cells and an increased rate of oxidation on addition of these substances they demonstrate further that malonate inhibits plant respiration. The stimulating effect of the substrates is often absent in fresh material, which is saturated with oxidizable substrates, but it is marked after storage, which depletes the tissue of substrates. The malonate inhibition is usually found only when the medium is acid (pH 5 or below) and when the concentration of malonate is relatively high (0.01 M and above). To obtain the same effects as in animal tissues ten- to a hundredfold concentrations of malonate are required. 

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