Localized, Cold-Induced Inhibition of Translocation in Mycelia and Strands ofSerpula lacrimans

Abstract

Thompson, W., Brownlee, C, Jennings, D. H. and Mortimer, A. M. 1987. Localized, cold-induce inhibition of translocation in mycelia and strands of Serpula lacrimans. —J. exp. Bot. 38: 889–899 The effect has been investigated of localized low temperature on translocation of ³²P across myceliui of Serpula lacrimans using two gas-flow detectors capable of recording radioactivity continuously. When the temperature of a band of mycelium was reduced to 0 ° C, radioactivity ceased to accumulai and in fact declined under the detector (number 2) separated from the source of radioactivity by tr cold-treated mycelium. In the mycelium beneath the other detector (number 1), closest to the source radioactivity, the rate of accumulation of radioactivity increased. When the temperature was raised t 20 °C, radioactivity began to accumulate in the mycelium under detector 2 and, apart from a sma fluctuation, continued to accumulate at a uniform rate. In the mycelium under detector 1, the accumulation of radioactivity stopped for a short time but then recommenced at a rate similar to thi found at 0 °C. In other experiments the distribution of radioactivity (¹⁴C) throughout the myceliui was measured at the end in homogenized samples. In these experiments a band of mycelium we subjected to 0 °C or to 20 °C for the whole experimental period, or only after the mycelium had bee translocating radioactivity already for 16 h. These experiments showed that the changes in the rate of accumulation of ³²P in living mycelium under the two gas flow detectors used for in situ measurements were not due to a reversal of the flow of translocation. The results are consistent with an hypothesis that a turgor-driven mass flow of solution is the mechanism for translocation in this fungus and are considered in relation to the results of similar experiments on phloem translocation in higher plants.