Carbon dioxide-induced changes in beech foliage cause female beech weevil larvae to feed in a compensatory manner

The phenology of Fagus sylvatica was unaffected by exposure to an atmosphere of elevated CO₂ (600 μL L^-1) after two years of fumigation. Non-significant changes in nitrogen and phenolic content of the leaves decreased the nutritional status of beech for female larvae in elevated CO₂ such that they responded by eating in a compensatory manner; males were unaffected. Rates of development, mortality and adult biomass of Rhynchaenus fagi were no different from those in ambient CO₂ concentrations (355 μL L ^-1). It is possible that, with the changes in leaf chemistry affecting the females, fecundity will be altered, with important consequences for populations of beech weevil.     

On the Phloem of Mimosa pudica L.

The phloem of Mimosa pudica L. was examined in view of somereports that the sieve elements in this plant show featuresnot previously described for these cells in Leguminosae. Inthe present study only a usual dicotyledonous type of sieveelement was recognized. The sieve elements pass through stagesof differentiation involving development and dispersal of P-proteinbodies, disintegration of nuclei, and appearance of plastidsstoring a starch staining red with iodine. Callose occurs onthe transverse or moderately oblique sieve plates. The phloemcontains secretory cells. They are wide and long and have transverseor more or less inclined end walls. In younger cells the endwall bears in the centre a conspicuous pit to which the protoplastsof the superimposed cells are firmly attached. In many oldercells the pit region is replaced by a perforation so that thecontents of superimposed cells may be completely merged. Itremains to be determined whether the perforation is presentin an intact plant or results from a rupture during sampling.The secretory cells accumulate material that gives a positivetest for carbohydrates and a negative test for proteins.     

The Distribution of O-antigen Types of Escherichia coli in Normal Calves, compared with Man, and their R plasmid Carriage

The distribution of O-antigen types of Escherichia coli in calves over a ten-month period has been determined. A total of 400 calves from separate farms located over a wide area of England and Wales have been surveyed. Of the 148 O-types recognized, 93 were found in calves, compared with 107 in a previous survey in man; 42 of these were common to both hosts. In calves 60% of isolates were resistant to at least one antibiotic. Of these, 71% belonged to ten O-types, 9 of which were found in man. It is concluded that calves form a potential reservoir of R plasmid carrying E. coli .     

Effect of Disbudding on Root Cytokinin Export and Leaf Senescence in Tomato and Tobacco

Bud removal and decapitation (disbudding) of plants of tomato(Lycopersicon esculentum Miller) and tobacco (Nicotiana tabacumL.) resulted in an increase in both the concentration and thetotal flux of cytokinin in bleeding xylem sap. There was a retardationin the rate of chlorophyll loss from leaves of disbudded plantsof both species. Ultrastructural examination of the chloroplastsof disbudded tomato plants revealed a maintenance of chloroplastintegrity, compared with chloroplasts from control plants. Itis suggested that the delaying of leaf senescence observed indisbudded plants is due to an increased availability of cytokininto these leaves.     

Marine Ostracoda of the Galapagos Islands and Ecuador

Marine algae collected from rock pools on Hood, Fernandina and Mosquera, in the Galapagos Islands, have provided a fauna of 26 ostracod species of which 14 are new. One genus, belonging to the Hemicytheridae, is also new and appears to be endemic to the Islands. From two littoral algal samples collected from Punta Canoa and San Pedro beach, Ecuador, an assemblage of some nine species, four of which are new, is also described. Two ostracods: Touroconcha lapidiscola and Loxoconcha (Lox-ocorniculum) lenticuloides , are the only species so far known to be present both in the Galapagos Islands and off the coast of Central and South America. One species: Cytherelloidea praecipua recorded from off Tobago and Clipperton Islands may be present in the Galapagos but this has not definitely been confirmed. The evolution in the Gulf Coast/Caribbean region of several ostracods and their subsequent dispersal westwards is discussed.