The effect of solar radiation on flavonoid biosynthesis was studied in bilberry ( Vaccinium myrtillus L.) leaves. Expression of flavonoid pathway genes of bilberry was studied in the upper leaves of bilberry, exposed to direct sunlight, in the shaded leaves growing lower in the same plants and in fruits. Bilberry-specific digoxigenin-dUTP-labeled cDNA fragments of five genes from the general phenylpropanoid pathway coding phenylalanine ammonia-lyase and from the flavonoid pathway coding chalcone synthase, flavanone 3-hydroxylase, dihydroflavonol 4-reductase, and anthocyanidin synthase were used as probes in gene expression analysis. Anthocyanins, catechins, proanthocyanidins, flavonols and hydroxycinnamic acids from the leaves and fruits were identified and quantified using high-performance liquid chromatography combined with a diode array detector. An increase in the expression of the studied flavonoid pathway genes was observed in leaves growing under direct sun exposure. Also, the concentrations of anthocyanins, catechins, flavonols and hydroxycinnamic acids were higher in the leaves exposed to direct sunlight. However, the concentration of polymeric procyanidins was lower in sun-exposed leaves, whereas that of prodelphinidins was slightly increased. The results give further support for the protective role of flavonoids and hydroxy cinnamic acids against high solar radiation in plants. Also, the roles of different flavonoid compounds as a defense against stress caused by sun exposure is discussed.
Studies performed in the former Soviet Union were reviewed to provide interception and weathering values for radioactive particles. None of these studies were available in the English language literature before or were considered in the international reviews. The estimated mass interception fractions ranged 0.2-1.4?m2?kg-1 may be explained by the size of the particles used in the research. The interrelationships among the interception fractions, plants biomass and size of radioactive particles were determined for different plants: spring and winter wheat, maize, rice, pasture and sown grass. A filtration model rather accurately approximated data for pasture grass and some other crops but does not reflect properly patterns of the interception fraction dependence on biomass for perennial sown grass. The values derived have been compared with some expected values reported by the IAEA's Handbook of parameter values for the prediction of radionuclide transfer in temperate environments (TRS 472) where possible. The information presented can be used in the current updating of parameters recommended for environmental impact assessments.