Bioassay aquatic plants

Lockhart, W.L., Billeck, B.N. and Baron, C.L. (1989) Bioassays with a floating aquatic plant (Lemna minor) for effects of sprayed and dissolved glyphosate, in M. Munawar, G. Dixon, C.L Mayfield, T. Reynoldson and M.H. Sadar (eds.), Environmental Bioassay Techniques and their Application Proceedings of the 1st International Conference held in Lancaster, England, 11-14 July 1988, Kluwer Academic Publishers, Dordrecht, Netherlands, pp. 353-359. 

Four bioassays a) 30 min acute bacterial test (Vibrio fischeri) b) 8d growth rate aquatic plant test (Lemna minor) c) 72h germination plant test (Lepidium sativum) and 8d root elongation plant test (Lepidium sativum) d) 72h germination plant test (Brassica rapa) and 8d root elongation plant test (Brassica rapa) Municipal and industrial solid waste leachates originating from landfills Unspecified pretreatment... 

Phenylpropanoid-type compounds have been isolated as the algal inhibitory constituents from the aquatic plant Acorus gramineus [92] using a filter paper-dish bioassay. It was noted that 1,2-dimethoxy-4-(E-3 -methyloxiranyl) benzene (10), l,2,4-trimethoxy-5-(Z-l -propenyl)benzene (11), l,2,4-trimethoxy-5-(E-3 methyloxiranyl)benzene (12), the three most abundant phenylpropanes isolated, were either inhibitory or not in each of the cyanobacterial strains tested which included Anabaena flos-aquae, Nostoc commune, and Synechococcus leopoliensis. 

Duckweed (Lemna pausicostata L.) has proved to be a sensitive bioassay for AAL-toxin, FBj and related compounds (75). Duckweed is a small aquatic plant that can be easily grown in the laboratory (75). Phytotoxic effects can be easily quantified by measuring chlorophyll loss and cellular leakage (74). AAL-toxin was about 10-fold more active than FBj in the duckweed bioassay, causing maximal effect at a 0.1 pM concentration. FBi, FB2 and FB3 caused effects identical to those of AAL-toxin in duckweed at 1 pM. The hydrolysis products, APi and AP2 were much less active, and FAi and FA2 were completely inactive in the duckweed bioassay (75). 

The objective of the research reported here was to develop sensitive bioassays which utilize near-whole plant systems of appropriate target aquatic weeds and which require little space and low volumes of incubation medium. Such bioassays could be used to help identify active fractions of chromatographically partitioned allelochemicals and could also be used in prinary screening procedures for newly synthesized agrichemicals. 

Seeds of lettuce and other species have frequently been used to bioassay for the allelopathic activity of plant exudates (17.18.19). As with the use of cell suspensions, there are certain advantages and disadvantages to this methodology. The experimental simplicity, small amounts of material required and short time frame are certainly attractive qualities. However, species used in such bioassays quite often do not represent the actual target species under consideration. This is especially true when terrestrial crop species are substituted for weeds of aquatic systems. Nevertheless, information obtained from such experiments are often valuable when used in conjunction with results of other assays. 

The Heavy Metal Binding Capacity (HMBC) test is a bioassay that helps to quickly determine metal bioavailability in aquatic environments. HMBC can also be applied to soils and to root exudates from aquatic and terrestrial plants. The HMBC test is based on MetPLATE, a bacterial toxicity test that selectively detects metal toxicity. 

During the last decade parathion has been the most used organo-phosphorus insecticide. It has been proved to be valuable in crop protection 27). However, using this compound so much has also resulted in numerous accidental intoxications, and many have been lethal 28). In aquatic environments parathion hydrolyzes to yield p-nitro-phenol or oxidizes to yield paraoxon (25, 26). Baker (29) has shown that substituted phenols aflFect the odor quality of drinking water. p-Nitrophenol may be chlorinated at a water treatment plant to produce an odorous product. The U. S. Public Health Service has adopted 1 /xg/liter as a limit for phenolic compounds in water (10). Paraoxon is more toxic to insects and mammals than the parent compound parathion (27). The lethal dose (LD50) for male white rats is 14 mg/kg for parathion while that determined for paraoxon is only 3 mg/kg (30). Bioassay studies with fathead minnows indicated a Median Tolerance Limit (TLni) (96 hours) for parathion of 1.4 mg/liter and 0.3 mg/liter for paraoxon. 

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