The conlents of total phenolics in three parasitic angiosperms, Ciisciita species, Orobanche aegyptiaca and Dendrophthoe falcata and their respective hosts, were colorimetrieally determined. A biochemical comparison was made of the phenolics on the basis of the ability of alcoholic extracts of the tissues to inhibit amylose phosphorylase in vitro.High concentration of phenolics seemed to be a general feature of parasitic angiosperms. An increase in the concentration of the phenolics occurred in the tissues of infected hosts, in comparison with controls. The phenolics of Orobanche and mistletoe had inhibitory activity against amylose phosphorylase, but those of Cuscuta developed the inhibitory ability only when growing on hosts which themselves possessed inhibitory phenolics. The inhibitory activity of host phenolics was sometimes altered as a result of infection by parasite. Although the hosts often exerted some influence on tbe concentration and the inhibitory activity of phenolics in the parasites, there was no direct relationship between host and parasite phenolics. The sum of the pbenolics in the tissues of parasite and tbe infected bost generally exceeded tbe pbenolics in the tissues of tbe control host. Tbe content of phenolics and their inhibitory activity did not appear to be directly related to tbe resistance of a bost or to tbe extent of its susceptibility to parasite infection. Physiol. Plant., 21,196S [949]

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The present autlhors have isolated a particleassociated cytochrome oxidase from the phylloclades of cactus plant and studied its kinetics. To our knowledge, this is the first report on cytoclhrome oxidase from a crassulacean plant.

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