Scientific publications

The effects of shungite rocks (ShR) from Turastamozero (1, 5, 25, 100%), Nigozero (1, 5, 10, 25, 100%) and Zazhogino (1, 5, 100%) deposits added to growing substrate on wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) plant growth and development were studied. Silica sand was used as a control substrate for plant growing.Plants were grown in growth chambers at a temperature of 23°C or 15°C, PAR 200 µmol m-2 s-1 and irrigated with a complete or 25% nutrient solution. Salt stress was provided by irrigation with 1,68% NaCl solution for 3 days. Periodic drought conditions were simulated by watering plants every 2-3 days.The results of the experiments have shown that plant growth and development is affected not only by the concentration of ShR in the substrate, but also the type (deposit location) of the ShR. There was recorded positive effect of TurastamozeroShR at 1 and 25% concentrations on the photosynthetic activity and accumulation od plant biomass. ShR from Nigozero deposit at concentrations above 5% inhibited plant growth and development due to high acidity of the substrate. The effects of ZazhoginoShR on these processes at 1 and 5% concentrations were insignificant. The use of ShR as 100% substrate have shown that only ShR from Turastamozero deposit is suitable for plant growing. In the substrates containing 100% ShR from Nigozero and Zazhogino the seeds did not germinate.Under mineral nutrition deficiency, wheat plants in the substate with 1 and 5% TurastamozeroShRhad larger biomass compared to control plants. Under periodic drought stress, the use of 1 and 5% ShR from all three deposits led to an increase of root biomass of barley, however, plant biomass was higher than the control only when 1% TurastamozeroShR was used. No positive effect of ShR on plant tolerance to salt and chilling stress was found. Based on our own results and literature data, we analyzed the hypothetical reasons of direct and indirect effects of ShR on plant growth and development. It is concluded that the practical use of ShR requires great care and further study, since without understanding the mechanisms of their effects on plants it is impossible to ensure their effective use in order to control growth, development and productivity. It is also obvious that the general term “shungite” is not Applicable in plant physiology and crop science as ShR from different deposits and mixed with other substrates in the fertilizing compositions can have very different, even opposing effects on plants.