The effects of UV exclusion on the soluble phenolics of young Scots pine seedlings in the subarctic.

The characteristics of UV-absorbing compounds, particularly soluble phenolics, were studied in needles of 63-day-old seed-grown Scots pine (Pinus sylvestris L.) seedlings of two provenances in a UV exclusion field experiment at Pallas-Ounastunturi National Park in Finnish Lapland (68 degrees N, 270 m a.s.l.). The experiment used the following plastic filters in exclosure treatments to manipulate the spectral balance of natural irradiance: (1) 'control' (a polyethene plastic filter); (2) 'UV-B exclusion' (a clear polyester filter); and (3) 'UV-B/UV-A exclusion' (a clear acryl plate). Polyethene transmitted 89% of the ambient levels of total UV (280-400 nm), polyester transmitted 75% of the total UV, but only 0.6% of the UV-B (280-315 nm) component, while acryl plate transmitted 0.2% of UV (280-360 nm). The research also included (4) 'Ambient' plants that were not subjected to any treatment exclosures. After the 58 day UV exclusion, significant (p<0.0001) differences due to treatments were determined for a kaempferol derivative, kaempferol 3-glucoside, and a quercetin derivative, the quantities of which ranged from 0.23 to 0.45, 0.42 to 1.34 and 0.39 to 0.75 micromol g FW(-1), respectively, depending on treatment and provenance. Overall, Scots pine seedlings grown at ambient UV radiation (PAS300, Caldwell's generalized Plant Action Spectrum (PAS) normalized at 300 nm, 72 mW m(-2)) or under a control had significantly (p<0.05) higher quantities of soluble phenolics than seedlings grown under UV-B or UV-B/UV-A exclusion treatments. There were no significant differences in the quantity of soluble phenolics between the two exclosure treatments or between the two Scots pine provenances. The sums of diacylated flavonol glucosides ranging from 3.75 to 4.55 micromol g FW(-1) depending on treatment and provenance, were already present at very low UV-levels under the UV-B/UV-A exclusion treatment. The present study indicated that soluble phenolics, particularly the diacylated flavonol glucosides, may provide an effective preformed protection for young Scots pine seedlings against UV-B and UV-A radiation.

Effects of emissions from copper-nickel smelters on the frost hardiness of Finns sylvestris needles in the subarctic region.

It has been proposed that freezing injuries play an important role in the forest decline phenomenon. In this study, the effect of emissions from the copper-nickel smelters in Monchegorsk and Nikel-Zapolyarnyi in the Kola Peninsula, south-west Russia, on seasonal changes in the frost hardiness of Pinus sylvestris L. needles were studied. The frost hardiness of current-year needles during autumn, winter, spring and early summer in 1991-1993 was estimated by the electrolyte leakage method and by visual estimation of the proportion of damaged needles at nine sites in Finnish Lapland, at five sites in the vicinity of Monchegorsk and at two sites in Norway, in the vicinity of Nikel. The foliar S, Cu, and Ni concentrations also analysed. There were no significant differences at any time of the year between the frost hardiness of pine needles at the sites in Norway and Finnish Lapland. However, in the winter, the degree of visual damage at -45 °C, the temperature close to the lowest recorded temperature in this area, was slightly higher at the sites near to Nikel than at the sites in Finnish Lapland. In the Kola Peninsula the frost hardiness was consistently lower at the sites located 10 km to the south and 36 km to the south-west of Monchegorsk than at the other sites (48-110 km to the south-west). The differences were greatest in early June, 1991, when frost hardiness was -2 °C and -8°C at the sites closest to Monchegorsk. At the same time, the frost hardiness at the other sites was e.-20 °C. There were slight differences between years, but the trends were the same. A clearly increasing gradient in the S, Cu and Ni concentrations was observed on moving towards the emission point source at Monchegorsk. Highly elevated concentrations were found within 40 km of the smelter. The results suggest that air pollutants from the copper-nickel smelter have predisposed the pines to freezing injuries, rhus contributing to forest decline in the Kola Peninsula.

Seasonal differences in freezing stress resistance of needles of Pinus nigra and Pinus resinosa: evaluation of the electrolyte leakage method.

Seasonal changes in freezing stress resistance of needles of red pine (Pinus resinosa Ait.) and Austrian pine (Pinus nigra Arnold) trees were measured by an electrolyte leakage method and by visual observation. During most of the year, freezing stress resistance determined by the two methods gave similar results. The electrolyte leakage method provided a good estimate of seasonal changes in freezing stress resistance except for red pine needles in their most winter-hardy state. To obtain a reliable estimate of freezing stress resistance in winter-hardy red pine needles it was necessary to combine the electrolyte leakage method with visual observations. When red pine needles survived exposure to -80 degrees C or lower, electrolyte leakage was never more than 30% even when the needles were exposed to a slow freeze-thaw stress of -196 degrees C. However, rapid freezing of red pine needles to -196 degrees C resulted in electrolyte leakage of over 80%. Red pine needles attained a much higher freezing stress resistance during the winter than Austrian pine. Red pine needles also acclimated and deacclimated faster than Austrian pine needles. An index of injury was developed based on the electrolyte leakage method ((R(2) + R(1))/2, where R(1) is the minimum % electrolyte leakage from noninjured tissue and R(2) is the maximum % electrolyte leakage at the highest injury) that reliably predicted freezing stress resistance of pine needles for most of the year. Important aspects for developing a successful index of injury for pine needles are: use of cut needles, vacuum infiltration and shaking during incubation in water.We conclude that: (1) during cold acclimation the cell wall properties of the pine needles changed and these changes, which appeared to differ in the two species, might explain the very low leakage of electrolytes from winter-hardy needles of red pine; (2) pine needles survive winter by developing the ability to tolerate extracellular ice formation, because after rapid freezing the needles were severely injured; and (3) red pine is adapted to a shorter growing season and colder winters than Austrian pine.

Characterization of a monoclonal antibody to human alpha-fetoprotein and its use in affinity chromatography.

A hybrid cell line secreting monoclonal antibodies to human alpha- fetoprotein (AFP) was produced by fusion of a mouse myeloma cell line with spleen cells from a BALB/c mouse immunized with human AFP. The affinity constant of the antibody was about 1.7 X 10(9) l/mol. When clones were grown in vitro, the highest concentration of specific antibody in the culture medium was 25 microgram/ml. A clone was transplanted intraperitoneally into pristine-primed BALB/c recipients. Ascites developed within 3-4 weeks of transplantation, and the maximal antibody concentration in the ascitic fluid was 2.5 mg/ml. The immunoglobulin fraction of ascitic fluid was coupled to cyanogen bromide-activated Sepharose and used for affinity chromatography of AFP. AFP containing less than 1% contaminating proteins was obtained by passing amniotic fluid through the column and eluting the adsorbed AFP with 4 mol/l urea. The monoclonal antibody was used for radioimmunoassay (RIA). The sensitivity obtained was 50 microgram/l, which is adequate for certain clinical applications.