DIN ISO 29200-2014 Soil quality - Assessment of genotoxic effects on higher plants - Vicia faba micronucleus test (ISO 29200 2013)《土质 高等植物遗传毒性效应的评估 蚕豆微核试验(ISO 29200-2013)》.pdf
《DIN ISO 29200-2014 Soil quality - Assessment of genotoxic effects on higher plants - Vicia faba micronucleus test (ISO 29200 2013)《土质 高等植物遗传毒性效应的评估 蚕豆微核试验(ISO 29200-2013)》.pdf》由会员分享,可在线阅读,更多相关《DIN ISO 29200-2014 Soil quality - Assessment of genotoxic effects on higher plants - Vicia faba micronucleus test (ISO 29200 2013)《土质 高等植物遗传毒性效应的评估 蚕豆微核试验(ISO 29200-2013)》.pdf(23页珍藏版)》请在麦多课文档分享上搜索。
1、May 2014 Translation by DIN-Sprachendienst.English price group 12No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 13
2、.080.30!%2 the seeds bearing these secondary roots are then used for the purpose of the test.This germination step of the Vicia faba seeds, necessary in both ways of exposure, can be started four days and eight days respectively for solid-phase and liquid-phase exposure before beginning the test.1)
3、LUFA soils are an example of a suitable product available commercially. This information is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO of this product.9DIN ISO 29200:2014-05 6.3 Conducting of the test6.3.1 Soils and soil materialsT
4、he dilutions of the test mixture are chosen within a geometric series with a factor not exceeding two and shall cover a large range of concentrations (e.g. from 0,01 % to 100 % ). These mixtures are prepared by diluting the soil with a reference soil.Each test shall include a negative control withou
5、t any test sample and a positive control (see 5.3).The direct exposure of the plant organisms to the different concentrations of the soil is performed by placing the germinated seeds (at least three per dilution) in a plastic pot containing 200 g of the tested soil and/or mixtures (see Figure 1) thr
6、oughout the exposure time between three and five days, according to obtain at least ten roots of 1 cm length.Figure 1 Method of direct exposure of the Vicia faba seeds6.3.2 Water extracts of soilThe concentrations of the sample under test are chosen within a geometric series with a factor not exceed
7、ing two and shall cover a large range of concentrations (e.g. from 0,01 % to 100 % for matrices). This range of concentrations is prepared by diluting the sample with the previously oxygenated Hoaglands medium (see Annex A).Each test shall include a negative control without any test sample and a pos
8、itive control (see 5.3).At the time of the test, the different solutions to be tested are extemporaneously brought up to a temperature of 24 C 1 C and well homogenised before exposure of plant organisms. This is carried out by placing the germinated seeds (at least three per concentration) in a glas
9、s container having a sufficient diameter in order to prevent, as far as possible, contact between the root tips and the container wall throughout the exposure time. The roots are immersed in a minimum volume of 200 ml of test solution (see Figure 2).10DIN ISO 29200:2014-05 Figure 2 Method of aqueous
10、 exposure of the Vicia faba seedsThe exposure time shall be at least 30 h, which corresponds to the approximate duration of the cell cycle. However the optimal exposure time recommended to detect genotoxic effects is 48 h to be sure that the cell cycle is ended and for a better practicability.6.4 Te
11、st environmentThe tests are performed in a climatic chamber (with an intensity of at least 5 000 lx and 16/8 photoperiod) at a temperature of 24 C 1 C. The liquid-phase test can also be carried out in darkness if necessary (e.g. maleic hydrazide).6.5 Cell preparationAt the end of the exposure period
12、, the roots are simply removed from the water extract, or carefully extracted from the soil. Then they are cleaned with deionised water and the last two centimeters of the secondary roots (ten or so roots per seed, chosen at random) are sampled and placed at 4 C for a minimum duration of one night i
13、n Carnoys solution. These root tips can then be stored on a long term basis in 70 % ethanol for a deferred observation or else can be hydrolysed in the case of an immediate observation.The root tips are then placed in distilled water for 10 min, hydrolysed in the hydrolysis solution at 60 C for 6 mi
14、n and retransferred into distilled water for a few minutes.For root cell observation, place a root tip on a slide after wiping it cautiously. Remove the first millimeter corresponding to the root cap and the meristematic region and, with the help of a scalpel, retain only the second millimeter which
15、 is made up of the subsequent generation of cells obtained after mitosis. Micronuclei scoring shall be done in this particular cells region (see Figure 3). All these steps may be done on a black background to see the different cell regions.The staining of the DNA is carried out by crushing the root
16、tips after addition of a drop of orcein; the coverslip can then be placed in position and squeezed to obtain a single layer of cells.11DIN ISO 29200:2014-05 It is recommended to carry out at least two cell spreadings (obtained with two different roots) per seed.1 mm 1 mmRoot capMeristem Cells formic
17、ronucleiscoringFigure 3 Longitudinal section of Vicia faba root showing the root cap, the meristem and cells region to be selected for micronuclei scoringIt is preferable to perform the scoring under blindfold conditions prior to their examination so that the person conducting the test is not influe
18、nced when counting the micronuclei (see Figure 4). The micronuclei observed in cells in division shall not be taken into account when determining micronucleus frequency. The results are expressed in number of micronuclei per 1 000 cells in interphase.Figure 4 Micronuclei in the cells of the root tip
19、s of Vicia faba (x 400)During the micronuclei scoring, it is highly recommended to verify the proper progress of the cell division (an essential condition for the micronuclei formation) by determining the proportion of cells in mitotic division (commonly called mitotic index). A genotoxic effect can
20、 be masked by a cytotoxic one (toxic with respect to the cell functioning) which would induce an underestimation of the genotoxic potential of the sample under test. The results are expressed in number of cells in division per 1 000 cells observed. All the stages of the mitosis are taken into accoun
21、t, from the prophase (when the chromosomes begin to condense) up to the telophase (when the chromatin of the two nuclei formed at each pole of the cell finishes decondensing).The microscopic examination of the slides is carried out under a magnification of 400. A minimum number of two slides is prep
22、ared for each of the three replicates for each concentration. Considering that 1 000 cells per slide are observed, the averages and standard deviations are therefore calculated on a minimum of 6 000 cells for each concentration.12DIN ISO 29200:2014-05 7 Assessment of the results7.1 Presentation of t
23、he dataThe results of the negative and positive controls and of the concentrations under test are expressed in terms of average number of micronuclei per 1 000 cells observed.7.2 Statistical analysisThe use of a non-parametric method (e.g. the Kruskal-Wallis test followed by Dunns multiple compariso
24、n test) is recommended in order to highlight the significant differences between the control and test concentrations.7.3 Interpretation of the results7.3.1 Positive testThe test is considered as positive if a statistically significant result with respect to the negative control is detected for at le
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