Abstract
Effect of p-chloromercuribenzoic acid (PCMB), dextran-bound PCMB (PMDT), 2, 4-dinitrophenol (DNP), sodium azide (NaN3) on the binding between the host plasmalemma and hyphal wall was determined by observing plasmolytic behavior of cells of potato tuber disks which had been treated with these inhibitors and inoculated with compatible or incompatible race of Phytophthora infestans. Light microscopic observations showed that regardless of the treatment with these inhibitors, the infected cells were plasmolyzed in a tent-type shape. This phenomena indicated that the host plasmalemma adhered the intercellular hyphal surface from the very onset of the infection. Electron microscopic observations of the plasmolyzed cells also showed that the plasmalemma of the cells which had been treated with NaN3, PMDT or water and then inoculated by an incompatible race, adhered to the surface of the infecting hyphae. These results clearly indicated that NaN3, DNP, PCMB and PMDT had no apparent effect on the firm binding between host plasmalemma and hyphal surface. Thus, the inhibition of the hypersenitive cell death of infected potato tissues by these inhibitors could hardly be due to interference of binding between the host plasmalemma and hyphal surface, which is necessary for the occurrence of the cell death.
