EXPERIMENTAL INVESTIGATION ON POPULATION PARAMETERS OF NEMATODES-PHYTOTROPHS DURING GROWING SEASON UNDER THE INFLUENCE OF HEAVY METALS

Abstract

Influence of zinc and lead salts on taxonomic diversity and population characteristics (population density, seasonal dynamics, age and eco-trophic structure) of nematodes-phytotrophs was experimentally studied. Parameters, sensitive and resistant to heavy metals, were detected. Taxonomic composition of nematodes was found to decrease in heavy metal treatments in some terms of observations. The most considerable changes were revealed for total number of nematodes-phytotrophs. After applying heavy metals into the soil (May – June) the total number of nematodes was increased, mostly due to plant parasite trophic group. Afterwards the ratio Asp/Pp was temporally changed. At the end of a season (August – September) a decrease in nematode population density was established in zinc and lead treatments in comparison with control. Such population characteristics as seasonal population dynamics and age structure were independent on pollutants. Particularities of heavy metal impacts on the nematodes were revealed. It was found that changes in population characteristics of nematodes-phytotrophs under the of heavy metal pollution were short-lived. Oт the base of principal component analysis it was shown that nematodes-phytotrophs were less susceptible to the effect of heavy metals once applied to the soil, then to natural fluctuations of abiotic factors.

Keywords

• phytotrophic nematodes
• taxonomic diversity
• seasonal dynamics
• popula- tion density
• age structure
• ecotrophic structure
• heavy metals
• lead
• zinc