Gramine and free amino acids as indicators of fluoride-induced stress in barley and its consequences to insect herbivory.

Barley leaves were sprayed with aqueous NaF, which caused accumulation of fluoride in the foliage, but no visible symptoms were detectable. No significant correlation was observed between foliar fluoride concentration and content of the indole alkaloid gramine after exposure to fluoride levels of 20 to 60 mg F liter-1. Fluoride exposure did not explicitly affect the performance of Carausius morosus or Rhopalosiphum paid on barley. After exposure to fluoride levels of 100 and 200 mg F liter-1, as NaF, fluoride treatment had a significant effect on gramine concentration of the first leaf of barley, being highest at a fluoride treatment of 200 mg liter-1, and there was a slight, but significant positive correlation between the log-transformed foliar fluoride concentration and log-transformed gramine concentration of the first leaf. Fluoride treatment increased levels of some individual free amino acids in barley foliage. Exposure of young barley to NaF in aqueous form caused accumulation of fluoride in barley foliage and resulted in increased levels of gramine in the first leaf and levels of some free amino acids in foliage. It is possible that the fluoride-induced concurrent increase in gramine concentration in barley leaves could override the eventual increase in nutritive value to herbivorous insects after fluoride exposure. More detailed biochemical studies of the induction of gramine production are needed to understand the fluoride effects in secondary metabolism of barley.

Deposition of motor vehicle emissions and winter maintenance along roadside assessed by snow analyses.

A vertical snow-sampling method, where a sample was taken throughout the snowpack, was used to estimate the pollutant load on a roadside where average daily traffic density was about 9100 motor vehicles. The snow samples were collected at two sites, forest and open field, at two distances of 10 and 30 m from the road. The concentrations of inorganic anions (Cl(-), NO(-)(3), SO(2-)(4)), total N, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated phenols (PCPhs) were analysed. The results suggest that on roadsides there is a deposition caused by road traffic emissions and winter maintenance which exceeds normal background deposition. Inorganic anions mainly in particle form, originating from winter maintenance, are deposited near the road. PAHs with low molecular weight (