The effect of inoculation of the root system with Cylindrocarpon magnusianum on plant performance exposed to heavy metal salts

Abstract

The effect of inoculation with endotrophic micromycete Cylindrocarpon magnusianum on the formation of adaptive physiological and biochemical reactions in test tomato plants under the action of heavy metal salts has been studied. The experimental design included plant inoculation with a fungus culture (control population) and these fungus populations were preliminarily grown on a pentose-dextrose agar medium with the addition of heavy metal salts in different concentrations. The inoculated plants were grown on substrates without the addition of heavy metal salts (control) and with the addition of zinc, copper, lead, and chromium salts in different concentrations similar to additions in agar when growing fungus populations. In experimental plants, we determined the content of photosynthetic pigments and ascorbic acid in the leaves (spectrophotometry), nitrates in the leaves (ionometric analysis), the aerial part and root system biomass by the gravimetric method, and the degree of fungal infection development of plants via the light microscopy method of macerated and colored fragments of the plant root system. No stimulatory effect, increasing the resistance of plants to the action of heavy metal salts when plants were inoculated with a control population of the C. magnusianum fungus, was revealed. A positive effect was revealed during the inoculation of plants with fungal populations, previously adapted to the action of salts of chemical elements, especially chromium and lead salts, and during further plants' cultivation on substrates with the introduction of these non-biogenic chemical elements hazardous to the life of plants. The effect is associated with the stability of the pigment system, the redistribution of plant biomass, and the synthesis of the antioxidant-ascorbic acid in the leaves. Intensive development of fungal infection in plant roots was also noted. The study results indicate the most effective partnership between the C. magnusianum fungus and the plant root system under stressful conditions for plant life.