Browsing by Subject "Akkumulation"

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Biomonitoring von Fluorwasserstoff : neue Ansätze zum Einsatz Höherer Pflanzen als Akkumulationsindikatoren
(2009) Blanckart, Peter; Fangmeier, Andreas
The standardised grass culture as described in VDI guideline 3957 sheet 2 has successfully been used for years to identify pollution related effects and to assess pollution load with hydrogen fluoride. At the moment, two directives are in preparation for the evaluation of the results from the exposure of standardised grass cultures which provide scales for judging and values for orientation on the basis of detailed studies. The directives will be published as VDI 3857 sheet 1 and sheet 2 as green print in 2009. The directive VDI 2310 sheet 3 is being revised as well. Its publication (green print) is also expected for 2009. According to no. 5.3 of the directive VDI 3957 sheet 2, samples with less than 2 g of dry substance have to be rejected. However, the rejection of these samples leads to a time gap for assessing of 14 days or even of 4 weeks. In this context it should be tested how the accumulation of fluoride after exposure with air containing hydrogen fluoride would be affected at lower growth rates. It should also be tested if samples of exposed grass with a minimum weight of less than the required 2 g of dry substance can be used for determining the pollution situation. To evaluate these problems, exposures were performed with standardised grass cultures and with modified methodology in an area ? the city of Ransbach-Baumbach ? which is highly contaminated by fluorides. Parallel to bioindication, the fluoride concentration in the air was assessed with radial symmetric passive samplers as a physicochemical method. By this means a direct comparison of the concentration of air pollutants with the pollutant concentration in the grass could be performed. The tests confirmed that the study area is indeed quite contaminated with fluoride from anthropogenic sources. The area around Ransbach-Baumbach can be considered as a hot-spot for higher fluoride concentrations within Germany. The results confirm that fluoride pollution in Central Europe is still an ongoing problem, even though the pollution is mostly scattered and small scale limited. Therefore, evaluation fundamentals for bioindication methods for fluoride (passive and active) should be worked out for the future, although fluoride accumulations are no longer regularly determined in large scale bioindication monitoring networks. The application of Deschampsia flexuosa (L.) Trin. as an accumulation indicator as a possible alternative to Lolium multiflorum Lam. could not be confirmed in this study; the deviations of fluoride concentrations in Deschampsia flexuosa (L.) Trin. and in Lolium multiflorum Lam. were too large in the spatiotemporal comparison. The measurements performed with radialsymmetric passive samplers did not show a good relationship between the hydrogen fluoride concentration in the air and the fluoride concentration F- [µg g-1 ds] in the Lolium grass cultures. There were only very low correlations between the fluoride concentration and the increase of biomass as raw and dry weight of Lolium multiflorum Lam. (R2 of 0.0258 and 0.0099 at two measurement stations, respectively). Since conventionally an R2 of ≥ 0,6 is required to indicate significant relationships in ecological/ecotoxicological field studies, no link between the increase of biomass and fluoride concentration for the accumulation indicator Lolium multiflorum Lam. is concluded. Therefore, it is recommended to revise the VDI guideline 3957 sheet 2 so that standardised grass culture samples of less than 2 g dry substance are also accounted for in the determination of the accumulation of air pollutants like fluoride in plants.
Genetische und physiologische Einflußfaktoren sowie deren Wechselwirkungen auf die Trichothecenbildung bei Roggen, Triticale und Weizen nach Inokulation mit Fusarium culmorum (W. G. Sm.) Sacc.
(2002) Reinbrecht, Carsten; Geiger, Hartwig H.
Fusarium culmorum causes specific hazards of cereal quality by the producion of trichothecenes. Prophylaxis by plant breeding can be highly effective. The aim of this study was to investigate the accumulation of trichothecenes in cereals with regard to host and fungal genotype, to physiological factors and the resulting interactions. To determine the effects of 6 environments (E), 2 inoculation dates (ID), 2 fungal isolates (I), and 5 conidia concentrations (C) and their interactions, field trials with up to 12 rye, 6 triticale, and 8 wheat genotypes (G) were conducted in 1995-1997. Kinetics of trichothecene in the heads were described with 6 harvest dates (H) in 2 host genotypes each. In a growth chamber, 2 levels of temperature (T) and 2 of relative humidity (R) were investigated by using 2 host genotypes each. Average deoxynivalenol (DON) accumulation of rye, triticale, and wheat was 41, 46, and 82 mg kg-1, respectively. Genotypes differed significantly in rye and wheat. In all cereal species, GxE interactions were important. In wheat, DON content was highly correlated to all resistance traits, whereas in rye only a tight correlation existed to the relative specific grain weight. In triticale and wheat, inoculation at full anthesis resulted in higher DON contents than inoculation at heading. In rye, no effect of inoculation date was found. In contrast, GxID interaction was significant in rye. The nivalenol (NIV) producing isolate led to lower trichothecene contents than the DON producing isolate. This effect was found to be significant only in rye and triticale. Significant GxI interactions occurred in wheat only. Even one week after inoculation, considerable DON concentrations could be obtained in harvested heads, especially in wheat. Maximum DON contents were observed between 3 and 6 weeks after inoculation (in wheat: partially above 300 mg kg-1). NIV contents were always lower than DON contents. Until full ripening, DON contents slightly decreased, whereas NIV contents increased continuously. HxE and HxI interactions were most important. Trichothecene content in chaff and spindles was 2-4 fold higher than in the respective kernels at 6 and 8 weeks after inoculation. With higher conidia concentrations, increasing contents of DON+3-Acetyl-DON were measured. GxC interactions were highly significant. Highest heritabilities were found in the upper concentration levels. When the relative humidity was high, trichothecene concentrations of kernels were superior. With the temperature, an inverse effect was obtained. It seems that GxT interaction contributed most to GxE in rye and wheat, in triticale also the GxR interaction. In conclusion, assisting resistance traits may replace an expensive quantification of trichothecenes in early generations. In advanced generations, tests should be conducted in several environments with high conidia concentrations, and a toxin analysis should be carried out directly.