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von Tiedemann A Weigel HJ Jäger HJ 《Environmental pollution (Barking, Essex : 1987)》1991,72(3):205-224
Spring wheat (Triticum aestivum L. cv. Turbo) was exposed in open-top chambers to six different ozone levels (8-h daily means from 12.4 to 122 microg m(-3)), to non-filtered air and to chamberless field conditions for 31 days from seedling stage through ear emergence. Powdery mildew (Erysiphe graminis DC. f.sp. tritici Marchal) which developed during the exposure period was significantly enhanced from 0.3/0.6% (two chamber replicates), 1.2/2.1%, 0.9/2.2% in charcoal-filtered air (CF) to 1.5/1.6%, 3.7/4.3%, 4.4/4.6% at the highest level of ozone, on the flag leaf, second and third leaf position, respectively. Post-exposure inoculation with Septoria nodorum Berk. led to increases of disease severity on the flag leaf from 40.9/43.6% in CF to 66.3/70.6% at the highest ozone concentration and on the ears from 15.7/16.5% to 26.3/26.6%. In the same comparison, severity of spot blotch following inoculation with Bipolaris sorokiniana (Sacc.) Shoem. (syn. Helminthosporium sativum Pamm., King et Bakke) was increased on the flag leaf from 3.6/8.9% to 12.3/23.4%. The three diseases examined correlated significantly with the ozone treatments in fumigated chambers. Disease severity was enhanced even on undamaged plant tissue (flag leaves). Infections of the two facultative pathogens on lower leaf positions started only in part from visible ozone lesions, mildew did not start from such lesions. No significant effects of ozone in the chambers on the saprobial colonization of the phyllosphere were detected, whereas there were marked differences in this respect between plants from the field and the chambers. At the highest ozone treatment, contents of chlorophyll a and carotenoids on the second leaf position declined significantly, which was associated with symptoms of premature senescence. Senescing effects of ozone are therefore assumed to be one major factor in predisposing wheat for necrotrophic leaf pathogens. Surprisingly, injurious and predisposing effects of ozone were completely absent in chambers supplied with non-filtered air containing ambient ozone at doses equivalent to those in CF + ozone chambers. Evidently, biological effects of ozone in pure air and in ambient air may differ markedly. 相似文献
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Werner Brack Michaela Hein Stefan Jansen und Peter von der Ohe 《Umweltwissenschaften und Schadstoff-Forschung》2007,19(3):A6
Ohne Zusammenfassung 相似文献
677.
Laturnus Frank von Arnold Karin Grn Christian 《Environmental science and pollution research international》2007,14(1):53-60
Goal, Scope and Background Sewage sludge produced in wastewater treatment contains large amounts of organic matter and nutrients and could, therefore,
be suitable as fertiliser. However, with the sludge, besides heavy metals and pathogenic bacteria, a variety of organic contaminants
can be added to agricultural fields. Whether the organic contaminants from the sludge can have adverse effects on human health
and wildlife if these compounds enter the food chain or groundwater still remains a point of controversial discussion.
Main Features This paper presents an overview on the present situation in Europe and a summary of some recent results on the possible uptake
of organic contaminants by crops after addition to agricultural fields by sewage sludge.
Results Greenhouse experiments and field trials were performed to study the degradation and uptake of organic micro-contaminants in
sludge-amended agricultural soil in crops, such as barley and carrots grown in agricultural soil amended with anaerobically-treated
sewage sludge from a wastewater treatment plant, but studies hitherto have revealed no immediate risks. Common sludge contaminants
such as linear alkylbenzene sulphonates (LAS), nonylphenol ethoxylates (NPE), polycyclic aromatic hydrocarbons (PAH), bis(diethylhexyl)
phthalate (DEHP), showed neither accumulation in soil nor uptake in plants.
Discussion It is assumed that the annual amount of sewage sludge produced in Europe will increase in the future, mainly due to larger
amounts of high quality drinking water needed by an increasing population and due to increasing demands for cleaner sewage
water. Application of sewage sludge to agricultural soils is sustainable and economical due to nutrient cycling and disposal
of sewage sludge. However, this solution also involves risks with respect to the occurrence of organic contaminants and other
potentially harmful contents such as pathogens and heavy metals present in the sludge. There have been concerns that organic
contaminants may accumulate in the soil, be taken up by plants and thereby transferred to humans via the food chain. Results
obtained so far revealed, however, no immediate risk of accumulation of common organic sludge contaminants in soil or uptake
in plants when applying sewage sludge to agricultural soil. With very high dosages of sewage sludge, there may be a risk for
accumulation of very apolar contaminants, such as DEHP, to the soil.
Conclusions Any conclusions on the safe use of sewage sludge in agriculture have to be drawn carefully, as the studies performed until
now have been limited. Further studies are required, and before final statements can be drawn, it is imminent to study a larger
variety of common crops and the effect sewage sludge application may have on a possible accumulation of organic contaminants
in the crops. Furthermore, a larger variety of organic contaminants need to be studied and special focus should be given to
contaminants newly introduced into the environment. Besides investigating possible plant uptake of organic contaminants, the
fate of these compounds in soil after sludge application need to be monitored too. Here, special attention has to begiven
to studies on degradation and the formation of degradation products, to weathering and to leaching effects on groundwater,
to the application of different crops on the same field (crop rotation), to the use of full-width tillage and strip tillage,
and to long term application of sewage sludge on the soil.
Recommendations and Perspectives There are environmental, political as well as economical incentives to increase the agricultural application of sludge. However,
such usage should be performed with care as there are also ways in which sludge fertilisation could harm the environment and
human health. Recently, a new European COST Action (859) has been established covering the field of food safety and improved
food quality. Part of the Action is dealing with the application of sewage sludge in agriculture. Before any political and
economical measures can be taken, the pros and cons have to be sufficiently investigated on a scientific level first.
ESS-Submission Editor: Prof. Elena Maestri (elena.maestri@unipr.it) 相似文献
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A. Guenther G. Kowalski N. von Engelhardt 《Behavioral ecology and sociobiology》2014,68(10):1661-1667
The prenatal social environment affects offspring development in most studied taxa with potentially lifelong consequences. To understand the adaptive significance of such maternal influences on offspring development, it is important to study their effects on fitness. In guinea pigs, social instability during pregnancy leads to delayed development of male offspring. This has been interpreted as an adaptation to high social densities, where young males need to queue for reproductive opportunities since they cannot out-compete older dominant males. The consequences for male reproductive success are, however, so far unknown. To study the effects of different prenatal social densities on offspring reproductive performance, we housed females individually or in small groups during late pregnancy. Offspring from both treatments were reared together in large groups until independence and thereafter housed in same-sex pairs of the same treatment. We then observed courtship, aggressive behavior, and reproductive success in a low-density context with one male from each treatment competing over access to two females. Sons born to individually housed females initiated more fights, had more social contacts, courted females more, and had a higher reproductive success than sons of group-housed females. Sons born to mothers experiencing low social densities before birth therefore perform better at low social group sizes, suggesting that male development may be adaptively adjusted to anticipated social densities, although performance under high densities still needs to be compared. 相似文献
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