Báo cáo lâm nghiệp: " Effects of polyaromatic hydrocarbons on the forest ecosystem and woody plants"

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Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Effects of polyaromatic hydrocarbons on the forest ecosystem and woody plants...

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Effects of polyaromatic hydrocarbons on the forest ecosystem and woody plants C. Rose J. Gérard 2 2 Dizengremel P. M. Berteigne 1Laboratoire d’Etude de la Pollution Atmospherique, INRA-CRF, Champenoux, 54280 Seichamps, and Laboratoire 2 de Physiologie Vegetale et Foresti6re, Universit6 Nancy I, BP 239, 54506 Vandoauvre, France soil and trees of the Vosges mountains Introduction evaluated. Simulation experiments were were also undertaken to estimate the PAH Polyaromatic hydrocarbons (PAH) are toxicity for plant cell metabolism. known to be animal carcinogens and/or bacterial mutagens. The few studies conducted on the effects of PAH on plant physiology describe them as hormone-like of Methods for extraction and analysis compounds. Carrot callus differentiation is PAH obtained with the carcinogen benzo- (a)pyrene (BaP) (Levine, 1951The direct application of a nutrient solution con- Oven-dried samples (5 d at 50°C) were extract- ed with cyclohexane (6 h) and purified using taining 10 ppb BaP to tobacco plantlets Sephadex LH 20fisopropanol preparative chro- induces a 100% growth-promoting effect matography. The dried extracts (containing (Graf and Nowak, 1966). Graf and Diehl standard naphthalene in cyclohexane) were (1966) reported a 3-5-fold increase in analyzed by gas chromatography and each PAH was qualitatively determined by mass endogenous PAH content during leaf yel- spectrometry. lowing. PAH are therefore assumed to be associated with plant senescence and chlorophyll degradation and could be considered as a new kind of senescence- Results inducing hormone. The problem of the presence in the atmosphere of organic pollutants of anthropogenic origin was PAH load in Vosgian soil recently raised (Krause, 1987) and their possible effect on higher plant physiology has to be questioned, since they can be organic layers L, F and H and The upper transported organo-mineral A, layer of Vosgian to remote areas (Matzner, the 1984). In this paper, the levels of PAH in were analyzed to determine their spe- soil
cific PAH contamination. An accumulation the needles and 120 ppb in the roots, process was found to occur in the H layer. whereas these values were, respectively, The fluoranthene contents of the L, F, H 40 and 30 ppb for healthy trees. The PAH layers increased, respectively, from 70 content decreased throughout the summer ppb to 200 ppb and 540 ppb, and then to a few ppb before increasing once more decreased to 80 ppb in the A, layer. Since in early autumn. This seasonal variation endogenous PAH are known not to points out that PAH removal could be exceed a few ppb, the reported values under the control of a photochemical- indicate an important anthropogenic enhanced catabolism. The differences contribution to soil contamination. The observed in June between healthy and accumulation rates (defined as the ratio: diseased trees suggest that this light- PAH in the H layer/PAH in the L layer), dependent detoxification process could be disturbed in the latter group. ranging from 3.5 for phenanthrene to 7.5 for benzo(a)pyrene, were found to be linked to their molecular weights. This PAH effects spruce seedlings on suggests that PAH physical properties (solubility, adsorption process) are the rate-limiting factors governing PAH fate in Spruce seeds were sown under sterile the upper soil layers. However, benzo- conditions (H MeOH). Once their , 0 2 fluoranthenes were an exception to this roots had germinated, they were trans- rule, since they showed a low accumula- planted into culture tubes containing nutri- tion rate (5.5) in comparison to what could tive woody pl;ant medium (WPM) (Smith be expected from their high molecular and McCown, 1983). Four weeks later, 14 weight and their low water solubility (
corresponding oxidation pro- tors than the by the treatment. Needle and root ed ducts. The effects of phenanthrene, fluor- growth were inhibited by PAH. anthene, pyrene, benz(a)anthracene, BaP Metabolites responded as early as day and benzofluoranthenes were investigated 12. Methionine, proline and phenylalanine on mitochondria isolated from Agaricus found to be the amino acids indicat- were bisporus. The most effective inhibitors PAH stress. Methionine and proline ing were the low molecular weight PAH. The levels remained high in the PAH-treated pattern of inhibition of the phosphorylating seedlings throughout the experiment, state 3 rate was found to be clearly non- whereas phenylalanine content increased linear, as previously observed (Dizengre- only after the higher light exposure. Fruc- mel and Citerne, 1988). Studies of the tose and glucose levels were higher in the effects of phenanthrene, fluoranthene and PAH-treated seedlings at the beginning of pyrene were made on lupin mitochondria. the experiment (days 12 and 19). The Fig. 1 shows the effects of fluoranthene on amount of protein initially decreased dras- lupin root and green cotyledon mitochon- tically in the PAH-treated spruces. Follow- dria. Generally, the respiration was half- ing high light exposure, the protein level inhibited with 5x10- M for root mitochon- 5 increased in the PAH-treated seedlings at dria and 2x10! M for green tissue a rate 2-fold higher than in control seed- mitochondria, which thus appeared to be lings. less affected by PAH. PAH effect on isolated mitochondria Conclusion The effects of PAH and their relative oxi- dation products were studied on mitochon- On the basis of this preliminary work, low dria isolated from green and non-green molecular weight PAH (phenanthrene, tissues from different plants. The action of fluoranthene and pyrene) can be consider- these compounds was investigated during ed to strongly affect physiological mecha- mitochondrial succinate oxidation. Studies nisms in higher plants. Further research is on potato tuber mitochondria showed that needed to fully understand their mode of PAH were more active respiratory inhibi-
activity could result from their aromatics. Arch. Bakteriol. 150, 49- action. PAH cyclic Hyg. 59 to senescence hormones. Soil similarity pollution by PAH could create an imbal- Graf W. & Nowak W. (1966) Promotion of growth in lower and higher plants by carcinoge- ance in the forest ecosystem leading to nic polycyclic aromatics. Arch. Hyg. Bacteriol. damage. However, the question severe 150, 513-5188 arises whether the PAH-induced yellowing Krause G.H.M. (1987) Forest decline and the of spruce needles could be related to that role of air pollutants. In: Acid Rain: Scientific frequently observed in the field and gener- and Technical ,Advances. (Perry R., Harrison ally thought to be due to Mg-deficiency. R.M., Bell J.N.E3. & Lester J.N., eds.), Selper Ltd., London, pp. 621-632 Levine M. (1951) The effects of sub- growth stances and chemical carcinogens on fibrous References roots of carrot tissue grown in vitro. Am. J. Bot. 38, 132-138 Matzner E. (1984) Annual rates of deposition of Dizengremel P. & Citerne A. (1988) Air pollutant polycyclic aromatic hydrocarbons in long-range effects on mitochondria and respiration. In: Air transported aerosols. Water Air Soil Pollut. 21, Pollution and Plant Metabolism. (Schulte-Hos- 425-434 tede S., Darall N.M., Blank L.W. & Wellburn A.R., eds.), Elsevier Applied Science, London, Smith M.A.L. & McCown B.H. (1983) A compar- pp. 169-188 ison of source tissue for protoplast isolation Graf W. & Diehl H. (1966) Concerning the natu- from three woody plant species. Plant Sci. Lett. caused normal level of rally carcinogenic poly- 28,149-156