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The aurea locus mutant (au (w)) of tomato contains less than 5% of the level of phytochrome in wild-type tissue as measured by in vivo difference spectroscopy. Immunoblot analysis using antibodies directed against etiolated-oat phytochrome demonstrates that crude extracts of etiolated mutant tissue are deficient in a major immunodetectable protein (116 kDa) normally present in the parent wild type. Analyses of wild-type tissue extracts strongly indicate that the 116-kDa protein is phytochrome by showing that this protein: a) is degraded more rapidly in vitro after a brief far-red irradiation than after a brief red irradiation (Vierstra RD, Quail PH, Planta 156: 158-165, 1982); b) contains a covalently bound chromophore as detected by Zn-chromophore fluorescence on nitrocellulose blots; and c) has an apparent molecular mass comparable to phytochrome from other species on size exclusion chromatography under non-denaturing conditions. The demonstration that the aurea mutant is deficient in this 116-kDa phytochrome indicates that the lack of spectrally detectable phytochrome in this mutant is the result of a lesion which affects the abundance of the phytochrome molecule as opposed to its spectral integrity.

Other TAs are known stimulants, such as cocaine and cocaine-related alkaloids. These will not be discussed in this review as these compounds are drugs of abuse and not related to food.

This study aimed to obtain insights into the presence of cadmium, lead, mercury and arsenic in feed materials and feed over time for the purpose of guiding national monitoring. Data from the Dutch feed monitoring programme and from representatives of the feed industry during the period 2007-13 were used. Data covered a variety of feed materials and compound feeds in the Netherlands. Trends in the percentage of samples that exceeded the maximum limit (ML) set by the European Commission, and trends in average, median and 90th percentile concentrations of each of these elements were investigated. Based on the results, monitoring should focus on feed material of mineral origin, feed material of marine origin, especially fish meal, seaweed and algae, as well as feed additives belonging to the functional groups of (1) trace elements (notably cupric sulphate, zinc oxide and manganese oxide for arsenic) and (2) binders and anti-caking agents. Mycotoxin binders are a new group of feed additives that also need attention. For complementary feed it is important to make a proper distinction between mineral and non-mineral feed (lower ML). Forage crops in general do not need high priority in monitoring programmes, although for arsenic grass meal still needs attention.

Abstract— Sensitivity to ultraviolet‐B radiation (UV‐B,280–315 nm) is generally reduced when background irradiance is high. We tested the involvement of photosynthesis in the amelioration of UV‐B damage by treating plants at high PAR (photosynthetically‐active radiation, 400–700 nm; 1000 μmol m‐2 s‐1) with supplemental UV‐B at double ambient levels of biologically‐effective radiation (18 kJ m‐2d‐1) and either “ambient” (450 μmol mol‐1) or short term elevated (750 μmol mol‐1) CO2 levels. Responses to UV‐B were assessed by photosynthetic gas exchange, leaf expansion and production of UV‐absorbing compounds (presumptive flavonoids) in cultivars of cucumber (Cucumis sativus L.) previously demonstrated to be relatively sensitive (cv. Poinsett) and insensitive (cv. Ashley) to UV‐B. Except for marginal leaf interveinal chlorosis observed in Poinsett, both cultivars responded similarly. UV‐B had little direct effect on leaf photosynthesis, but it did cause reductions in leaf area and corresponding increases in leaf dry matter per area. Increased CO, stimulated plant growth, counteracting the effect of UV‐B on leaf growth and indicating an important role for photosynthesis. In contrast, the accumulation of UV‐absorbing flavonoid compounds was enhanced by UV‐B exposure but was not affected by COz enrichment.

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