Cress test

S. Verstichel- Organic Waste Systems (OWS) Final Report, Ecotoxicity Tests—Cress Test. Summer Barley Plant Growth Test Earthworm, Acute Toxicity Test Daphnia, Acute Toxicity on Compost Residuals of EPI-TDPA-Study CH-3/2 (Cress Test), Study CH-3/3 (Summer barley plant growth test) Study CH-3/4 (Earthworm, acute toxicity test). Study CH-3/5 (Daphnia, acute toxicity test)... 

Bioassay of Extracts. Extracts tested for the presence of cyclohexi-mide were also bioassayed for phytotoxicity. The extracts were redis-sOlved in acetone, and 0.2 mg in 2 pi was applied to 6-cm-dia disks of filter paper. The extract was distributed on the paper with 0.2 ml of methanol. The disks were dried with warm air, placed in 1.5 x 6 cm petri dishes, and moistened with 1.5 ml distilled water. Ten cress seeds were placed on the paper, and after incubation for 3 d at 28 C radicle length of the seedlings was measured. 

Table II. Effect of microorganisms on solid and in liquid medium on growth and germination of cucumber (Cucu), barnyard grass (Bygr), and garden cress. Data are for all microbial isolates tested in liquid medium...

J20 stimulated radicle growth of barnyard grass. Cress radicle growth was not stimulated by culture broth of any of the isolates tested. 

Table III. Effect of culture broth (2 ml/petri dish) and dichloromethane extract of culture broth (0.2 mg/petri dish) on cress radicle growth, as related to presence of cyclohex-imide. Data are for all isolates tested in liquid culture whose broth inhibited cress radicle growth to 50% of controls...

Aliquots of oligopeptide compounds to be tested were dissolved in ethyl acetate. One milliliter aliquots of the samples were pipetted onto filter paper and 15 lettuce or cress seeds were uniformly distributed on the the filter paper surface and allowed to imbibe in the dark at 20 to 25 C for 24h. The samples were subsequently placed in a growth chamber in continuous light at 28°C for 72h, and the root lengths were measured. 

The procedure of Chen ef al. (C7) separated the ascorbic acid on paper using n-butanol or phenol saturated with oxalic acid to retard decomposition. A preliminary preparative separation could be used to concentrate the sample. Qualitative identification was made from the R/ of the spots located by spraying with 0.08 % 2,6-dichlorophenolindophe-nol, and quantitative analysis by elution with oxalic acid and titration with the same dye. Recoveries from urine and cress seedlings were 85 % or more at even the lowest concentrations tested (0.5 mg/ml), and the method could detect 1-2 fig ascorbic acid per cm of paper. The method clearly separated L-ascorbic acid and D-araboascorbic acid as well as hydroxytetronic acid, reductinic acid, and reductone. 

Metham is used for general soil disinfection, in greenhouses and under field conditions at a rate of 11 litres of the 32.7% solution per 100 m. At this rate it kills all plants and seeds, thus the planting of crops must be delayed for about 2 weeks after treatment. The termination of the phytotoxicity of treated soil must be checked by the cress-seed tests. 

Crude extracts, fractions, or pure compounds are dissolve in an appropriate solvent, then serially diluted to obtain the desired concentration. Solutions are filter sterilized prior to bioassay. In a glass petri dish, a known quantity of test solutions are applied onto a filter paper (Whatman No. 1) and allowed to evaporate to dryness. To each petri dish, 10-15 seeds of the test species are added followed by deionized Water (1.5 ml). For example, curley cress (Lepidium sativum L.)is used as an example for a broad leaf species. Negative controls consist of an equal amounts of evaporated solvent and deionized H2O. All treatments are replicated thrice. Petri dishes are then covered, randomized, and placed in a humid chamber for 72 h at 26°C. Thereafter, root lengths are measured and an I50 (50% germination or growth inhibition) level is determined for each of the treatments. Data are subjected to ANOVA and means are compared by an LSD test [92]. 

Other plant hormones, such as auxins and GAs. Finally, selected compounds were assayed using a cress hypocotyl elongation test. It has been demonstrated that cress is very sensitive to an internal deficiency of BRs and is therefore a useful species for evaluating BR biosynthesis inhibitors [7-8],... 

Frozen vegetables may have total counts of up to 100000 g. Exotic imported vegetables should be tested for coliforms, E. coli and enterococci as human waste is widely used as a fertiliser in Asia. Cress has also been implicated in a number of food poisoning incidents and should be tested for E. coli, as it may have been grown in water polluted with sewage. 

Fig.5 Western Blot of LHCP. In addition to pigment analysis, we tested cress plants for presence of LHCP after 12h irradiation. LHCP levels decreased after incubation with complexing agents. This seems to be in parallel with the chlorophyll content (Fig.l) after the same illumination time.

Phytotoxicity testing can be conducted on two classes of flowering plants. These are monocots (plants with one seed leaf) and dicots (plants with two seed leaves). Representatives from both of these classes are typically used in toxicity testing - summer barley to represent monocots and cress to represent dicots. Test involves measuring the yield of both of these plants obtained from the test compost and from the control compost. 

The ecotoxicological impact of lactic acid-based polymers was evaluated by biotests, i.e. by the Flash test, measuring the inhibition of light production of Vibrio fisheri, and by plant growth tests with cress, radish, and barley [16]. Poly(lactic acid)s, poly(esterurethane)s... 

---