A Study On Cultivation Method And Toxicity Test Of Soil Nematodes

Soil nematodes, as a kind invertebrate most abundant in soil, which have many biologicaladvantages and are treated as a kind of instruction creatures, have been widely used in toxicitytest to monitor and evaluate the soil environment. In previous researches, caenorhabditiselegans were frequently used as instruction nematodes, while the researches about soilnematodes in farmland were rarely reported. This paper conducts some primary researches onthe cultivation method and condition of soil nematodes, and focuses on the research on thetoxicity test of the effect of monocrotophos, as a poison, to the soil nematodes and focuses onthe effect of nomocrotophos to the soil nematodes’ motor ability. And results showed that:According to the comparison of three kinds of medium, lettuce egg yolk medium wasmore suitable than the other two media for the cultivation of the soil nematode in laboratory,and the best cultivation temperature is25℃.That soil nematodes’ LC₅₀ value is282mg/ml, which was lower than the caenorhabditiselegans’ half death rate, in the acute toxicology test in monocrotophos by soil nematodes inrice paddies after assimilation, proved that soil nematodes are more sensitive to theenvironment changes.The exposure test on soil nematodes’ movement behavior in monocrotophos of differentconcentration shows that: in the group of0.3mg/L of monocrotophos, there was no significantdifference, compared with blank control group, in the frequency of soil nematodes’ bodybending, backward swings（0.05＜P＜0.1）, swings in the shape of and head swings; in thegroups of3.0mg/L and30mg/L, the above frequencies decrease distinctly（P＜0.01）. Thebody bending frequency decreased by17.1%, head frequency by18.3%and the forwardswings by20.2%in the group of3.0mg/L, while those data for30mg/L group are46.7%,45.4%and47.9%.