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461.
茚虫威对斑马鱼的急性毒性及遗传毒性 总被引:1,自引:0,他引:1
茚虫威属噁二嗪类新型广谱高效杀虫剂,在农业生产中有着重要作用,近年来随着用量的增加,由此产生的对水生生物的影响越来越受到重视。使用斑马鱼进行茚虫威的急性毒性作用实验,并采用微核试验、彗星试验、Annexin V-FITC/PI双染色检测观察染毒后的斑马鱼是否被诱导产生遗传毒性。结果表明:在24 h、48 h、72 h、96 h,茚虫威LC50值分别为2.263mg·L-1、2.184 mg·L-1、2.184 mg·L-1、2.133 mg·L-1。茚虫威对斑马鱼急性毒性属中等毒性。96 h茚虫威浓度为1.98 mg·L-1和2.16 mg·L-1时,斑马鱼的微核率与对照组相比达差异极显著水平(P0.01)。采用彗星试验检测斑马鱼肝脏DNA损伤,结果显示斑马鱼暴露于高浓度1.98 mg·L-1和2.16 mg·L-1茚虫威后,与对照组相比,斑马鱼的DNA损伤均表现为极显著差异(P0.01)。采用Annexin V-FITC/PI双染色流式细胞仪法检测,结果表明染毒后24 h斑马鱼肝细胞出现细胞凋亡现象。实验结果进一步表明,茚虫威对斑马鱼短期染毒后诱导细胞凋亡,表现出遗传毒性。 相似文献
462.
6+ ), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), selenium (Se), zinc (Zn), and polychlorinated biphenyls (PCBs). Water-column,
bed-sediment, and fish-tissue (fillets) data collected by five government agencies comprised the ambient data set; effluent
data from five registered facilities comprised the compliance data set. The nonparametric Mann-Kendall trend test indicated
that 33% of temporal trends in all data were statistically significant (P < 0.05). Possible reasons for this were low sample sizes, and a high percentage of samples below the analytical detection
limit. Trends in compliance data were more distinct; most trace elements decreased significantly, probably due to improvements
in wastewater treatment. Seven trace elements (Cr, Cd, Cu, Pb, Hg, Ni, and Zn) had statistically significant decreases in
wastewater and portions of either or both ambient water and bed sediment. No trends were found in fish tissue. Inconsistency
in trends between ambient and compliance data were often found for individual constituents, making overall similarity between
the data sets difficult to determine. Logistical differences in monitoring programs, such as varying field and laboratory
methods among agencies, made it difficult to assess ambient temporal trends. 相似文献
463.
464.
泥炭生化复合肥料田间对比试验 总被引:1,自引:0,他引:1
本文介绍了泥炭生化复合肥料与其它几种肥料的田间对比试验。试验结果表明,泥炭生化复合肥料的肥效优于其它几种肥料,且对农业生产的增产效果显著 相似文献
465.
Gary L. Ketcheson Walter F. Megahan John G. King 《Journal of the American Water Resources Association》1999,35(1):83-98
ABSTRACT: Erosion and sedimentation data from research watersheds in the Silver Creek Study Area in central Idaho were used to test the prediction of logging road erosion using the R1-R4 sediment yield model, and sediment delivery using the “BOISED” sediment yield prediction model. Three small watersheds were instrumented and monitored such that erosion from newly constructed roads and sediment delivery to the mouths of the watersheds could be measured for four years following road construction. The errors for annual surface erosion predictions for the two standard road tests ranged from +31.2 t/ha/yr (+15 percent) to -30.3 t/ha/yr (-63 percent) with an average of zero t/ha/yr and a standard deviation of the differences of 18.7 t/ha/yr. The annual prediction errors for the three watershed scale tests had a greater range from -40.8 t/ha/yr (-70 percent) to +65.3 t/ha/yr (+38 percent) with a mean of -1.9 t/ha/yr and a standard deviation of the differences of 25.2 t/ha/yr. Sediment yields predicted by BOISED (watershed scale tests) were consistently greater (average of 2.5 times) than measured sediment yields. Hillslope sediment delivery coefficients in BOISED appear to be overly conservative to account for average site conditions and road locations, and thus over-predict sediment delivery. Mass erosion predictions from BOISED appear to predict volume well (465 tonnes actual versus 710 tonnes predicted, or a 35 percent difference) over 15 to 20 years, however mass wasting is more episodic than the model predicts. 相似文献
466.
467.
Heavy Metal Toxicity Responses of Two Willow (Salix) Varieties Grown Hydroponically: Development of a Tolerance Screening Test 总被引:1,自引:0,他引:1
The E.U. funded BIORENEW project is investigating bioremediation of industrially degraded land using biomass fuel crops, including willow. One of its goals is to develop a rapid screening test to assess the metal tolerance of large numbers of willow varieties. This should reflect how a plant will respond to heavy metals under various field conditions and in the long term. A preliminary experiment tested two varieties of contrasting ability to thrive in metal-contaminated soils. Trees were exposed to a metal cocktail in three different strengths of background solution. An appropriate strength solution (1/4 strength Hoaglands) was identified for differentiating variety performance, based on its effect on the biomass of plant fractions relative to control fractions. This is a response to heavy metals which can be quantified rapidly and simply. The relative performance of the varieties was comparable to their performance in field studies. This test will be used to assess the tolerance of further varieties. 相似文献
468.
By scoring the chromosome number of developing embryos, we show that the sex ratio bias of the African social spider Stegodyphus dumicola Pocock is the result of an overproduction of female embryos. Only 17% of 585 embryos sexed from 14 egg sacs were male, a
significant departure from a 1:1 sex ratio. We also explored the possibility of direct control of the sex of individual offspring
in this species by examining the variance in the number of males per sac and the spatial distribution of male and female embryos
within the sacs. We postulated that a variance in the number of males per sac lower than binomial (i.e., underdispersed or
precise sex ratios) or a non-random distribution of male embryos within the sacs would suggest direct control of the sex of
individual offspring. We found that the variance in the number of males per sac was indistinguishable from binomial and significantly
larger than expected under exact ratios. Likewise, the spatial distribution of male embryos within three sacs examined was
no more clustered than expected by chance. The sex ratio biasing mechanism in this species, therefore, apparently only allows
control of the mean sex ratio but not of its variance. We present randomization and Monte Carlo methods that can be applied
to test for departures from a random spatial arrangement of male and female embryos in an egg mass and for departures from
binomial or exact ratios when not all members of a clutch have been sexed.
Received: 21 October 1998 / Received in revised form: 23 March 1999 / Accepted: 26 April 1999 相似文献
469.
通过对某双线电气化铁路隧道内空气细菌污染状况的调查,结果表明,隧道内空气不同程度地受到细菌污染,其细菌数与隧道深度有较强的正相关性,与湿度也有一定的正相关性,与温度(23℃~36℃)有一定的负相关性。指出,隧道内无阳光照射,气温变化小,空气流动性差,阴暗潮湿的环境有利于微生物生长繁殖,并可能影响隧道内作业工人、列车司乘人员和旅客的身体健康。 相似文献
470.
大型蚤毒理试验应用与研究进展 总被引:3,自引:0,他引:3
大型蚤作为国际公认的标准试验生物 ,其毒理试验被许多国家定为毒性必测项目 ,各国纷纷建立了自己的标准方法 ,因此有着广阔的应用前景。在分析中 ,主要介绍了大型蚤的试验培养技术和国内外对其毒理试验方面的研究概况。 相似文献