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101.
MIKI AIDA KAZUYUKI ITOH HIROAKI IKEDA NAOKUNI HARADA YASUO ISHII KENJI USUI 《Weed Biology and Management》2004,4(3):127-135
Paddy herbicides have the potential to cause adverse effects on non-target plants. Susceptibilities of some aquatic ferns ( Azolla japonica Franch. et Savat., Isoetes japonica A. Braun, Marsilea quadrifolia L. and Salvinia natans All.) and duckweeds ( Lemna minor L. and Spirodela polyrhiza Schleid.) to paddy herbicide bensulfuron methyl (BSM) were evaluated with a 20 day exposure experiment using 200 cm2 pots. The BSM concentrations in the surface water of monitoring pots with no plants dissipated exponentially with half lives of 3.5 and 3.9 days at application rates of 15 and 150 g ha−1 , respectively. The BSM concentrations in the surface water 1 day after application in the culture pots were comparable among plant species, and were lower than those in the monitoring pots. Bensulfuron methyl reduced the plant growth in all species. I . japonica showed the lowest intrinsic relative growth rate (RGR) and the lowest susceptibility with an effective dose resulting in 50% growth inhibition (ED50 ) of 21 g ha−1 . Except for I . japonica , the RGR of the duckweeds was similar to the ferns, and ED50 for the duckweeds was higher than the ferns. ED50 for Sa . natans , A . japonica and M . quadrifolia were 1.1, 1.8 and 1.2 g ha−1 , respectively, which were smaller than 1/20 of the recommended field dose (51–75 g ha−1 ) and ranged from 1/2 to 1/6 of ED50 for L . minor and Sp . polyrhiza (6.5 and 3.2 g ha−1 , respectively). These results suggest that BSM application in paddy fields and its runoff in some localities is expected to have adverse effects on the growth of Sa . natans , A . japonica and M . quadrifolia . 相似文献
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应用特异性强的间接酶联免疫法,同时检测4种硝基呋喃类代谢物、氯霉素(CAP)和氟苯尼考(FF),建立快速分析水产品中6种药物残留量的方法.样品用盐酸进行消化,再由乙酸乙酯提取,使用酶联免疫试剂盒进行检测.实验结果显示,6种分析物均在其线性范围内,线性系数均大于0.995.在加标浓度为0.1、0.5和1.5μg/kg的加... 相似文献
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- 1. Current monitoring strategies of governmental organizations tend to be focused on relatively large flowing and standing waters, and until recently those polluted by point sources. Consequently areas of high conservation interest tend to be understudied, and defining reference conditions, as required by current legislation, is difficult to achieve.
- 2. In order to address this imbalance, water samples have been collected and analysed once in each of four seasons during 2003 from 72 locations within a 100 km2 area of the oligotrophic River Spey catchment in NE Scotland. The sampling design included examples of running water (headwater streams and the main rivers) and standing water (lochs, lochans, pools, ditches, backwaters, bogs). Altitude ranged from 220 to 980 m and incorporated a climatic regime from cool temperate to sub‐alpine. Each sampling campaign targeted low‐flow conditions to evaluate steady‐state nutrient concentrations.
- 3. Concentrations of the major soluble nutrients nitrogen and phosphorus demonstrated high spatial and temporal variability, with soluble organic and molybdate unreactive forms generally being dominant. Concentrations of ammonium‐N, nitrate‐N and soluble reactive phosphorus were extremely small, with 50% of samples falling below 8, 5 and 1 µg L?1, respectively, during spring and summer.
- 4. Sampling sites were grouped either by water‐body type or by the properties of their immediate biophysical zone. Together these two groupings explained 33–38% of the variance in water chemistry. Certain changes were detectable across most habitats and biophysical zones.
- 5. A decline in the concentration of nitrate that occurred in reaches downstream from certain headwater streams draining the mountain areas indicated the potential for its within‐stream utilization. Inorganic N dynamics differed between small streams and large rivers.
- 6. Landscape‐scale patterns were recorded in spring and summer nutrient availability with inorganic N and P thresholds (arbitrarily defined) of 10 and 1 µg L?1, respectively.
106.
水产品由于其丰富的营养价值,在世界范围内的需求量持续增加。然而,水产品消费与加工过程中产生的大量副产物,带来了严重的资源浪费和环境污染等问题。鉴于此,水产品加工副产物依据其不同特性已经被开发应用到诸多领域。其中,水产品副产物蛋白因其独特的功能特性与较高的经济附加值,在实际生产中得到了广泛的回收和利用。因此,本文综述了现阶段广泛用于回收水产品副产物蛋白的物理学、化学和生物学方法,同时,介绍了鱼类、甲壳类和贝类副产物蛋白高值化利用的研究进展,并对水产品副产物蛋白未来的发展趋势进行展望,旨在进一步提升水产品副产物资源的综合利用潜力,促进我国水产品加工业高质量发展。 相似文献
107.
影响池养鳜健康的关键水生态因子 总被引:1,自引:0,他引:1
池塘生态系统是一个动态、多因素、非典型的复杂系统,用单因素统计法难以研究池塘养殖中的生态问题.在16口鳜养殖塘进行试验(总面积为4.7 hm2),每两周采样一次,获取鳜健康指标和pH、铵氮、硝酸盐氮、二氧化碳、总碱度、镁和细菌总数等17项水生态因子的87组监测数据,并对数据进行数理统计,研究探讨用权重因子、偏回归平方和、F检验值和相关系数等统计量优化进入鳜健康模型的因子.在满足一定准确度条件下,优选出用pH、铵氮、硝酸盐氮、二氧化碳、总碱度、镁浓度和细菌总数等7项因子为自变量,利用回归技术,求出它们与鳜健康指标(y)的关系模型为的非线性模型,模型的预报准确率为92.4%.借助所得模型进一步推导出对鳜健康指标影响由大到小的因子是细菌总数、二氧化碳、pH、铵氮,他们的最佳取值范围依次为(13~27)×104 cfu·L-1、小于3 mL·L-1、7.5~8.0、0.5 mL·L-1. 相似文献
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109.
近期暴发的新冠肺炎使人们谈食色变,针对水生野生动物的保护与利用问题备受社会各界人士的关注。水生野生动物作为一种宝贵的自然资源同时也是生态系统中的重要组成部分,其价值不仅体现在维持生态平衡上,也体现在满足人类养殖开发与利用上。水生野生动物在实现社会经济可持续发展,改善和丰富人民的物质和文化生活中具有不可代替的重要位置。但是,在针对水生野生动物保护与利用之间是存在矛盾的。本文从水生野生动物保护与养殖利用的关系等方面进行阐述,并从水生野生动物野外资源保护和规范水生动物的繁殖与利用等方面进行展望。呼吁社会积极鼓励和宣传水生野生动物合理的驯养繁殖及加工利用事业,引导消费者正确食用安全的驯养产品,进而实现扩大、改善水生野生动物生存空间和环境,实现水生野生动物种群规模不断发展壮大,最终实现水生野生动物资源的可持续性与合理的永续利用。 相似文献
110.
Effects of chlorpyrifos in freshwater model ecosystems: the influence of experimental conditions on ecotoxicological thresholds 总被引:7,自引:0,他引:7
Three experiments were conducted to determine the impact of the insecticide chlorpyrifos (single applications of 0.01 to 10 microg AI litre(-1)) in plankton-dominated nutrient-rich microcosms. The microcosms (water volume approximately 14 litres) were established in the laboratory under temperature, light regimes and nutrient levels that simulated cool 'temperate' and warm 'Mediterranean' environmental conditions. The fate of chlorpyrifos in the water column was monitored and the effects on zooplankton, phytoplankton and community metabolism were followed for 4 or 5 weeks. The mean half-life (t1/2) of chlorpyrifos in the water of the test systems was 45 h under 'temperate' conditions and about 30 h under 'Mediterranean' environmental conditions. Microcrustaceans (cladocerans and copepod nauplii) were amongst the most sensitive organisms. All three experiments yielded community NOEC (no observed effect concentrations) of 0.1 microg AI litre(-1), similar to those derived from more complex outdoor studies. Above this threshold level, responses and effect chains, and time spans for recovery, differed between the experiments. For example, algal blooms as an indirect effect from the impact of exposure on grazing organisms were only observed under the 'Mediterranean' experimental conditions. The relatively simple indoor test system seems to be sufficient to provide estimates of safe threshold levels for the acute insecticidal effects of low-persistence compounds such as chlorpyrifos. The robustness of the community NOEC indicates that this threshold level is likely to be representative for many freshwater systems. 相似文献