This article presents a report "IVth Meeting of the International Council for the Study of Viruses and Virus Diseases of Grapevine, Colmar," by Institut National de la Recherche Agronomique. This report of the 4th symposium on viruses attacking the grapevine provides an up-to-date review of the present problems and also includes paper on several diseases probably caused by mycoplasms. The increasing importance of clonal breeding of vines makes it doubly important that virus-free stocks are used.
Populations of viable bacteria and fungi were shown to exist in various strata of peat formed in the Florida Everglades. The populations present were quantitatively and qualitatively different in three distinct peat-forming habitats and at various depths in the peat profiles. Relatively few pieces of peat taken from horizons below the surface were colonized by actively growing fungi or actinomycetes. Direct observation of peat confirmed some features of the cultural studies. Bacteria were mostly present in small groups of two to six cells and most of the hyphae recorded were apparently formed by Actinomycetales rather than the fungi. The significance of these data in relation to possible long-term changes in the peats is discussed. [ABSTRACT FROM AUTHOR]
In assays of acid phosphatase activity with p-nitrophenyl phosphate as substrate, the low activity found in fluids removed from around roots in liquid medium was not affected by the presence of micro-organisms. Most phosphatase activity of intact seedling roots was associated with the root surface and was not increased by micro-organisms in the rhizoplane; in some experiments activity was significantly reduced by soil micro-organisms. Inoculation of roots with pure cultures of bacteria and a fungus known to have phosphatase activity did not increase this activity of the roots. These results are contrasted with those of other workers. Possible application to the soil situation is discussed. [ABSTRACT FROM AUTHOR]