Influence of cyanobacterium Nostoc paludosum and its exometabolites on barley growth

The chemical composition and influence of exometabolites of the soil cyanobacterium Nostoc paludosum 18 on the barley plants of Izumrud variety were studied. Exometabolites from the culture liquid were extracted with hexane and carbon tetrachloride. Organic substances in the studied substrates were determined by high-performance liquid chromatography on the Shimadzu LC-20 chromatograph, Prominence series with a diode-matrix detector and gas chromatography on the GС-2014 Shimadzu chromatograph with a TCD-2014 detector (Japan). The intensity of lipid peroxidation in barley cells was studied by the accumulation of malondialdehyde using SPEKOL 1300 spectrophotometer (Analytik Jena, Germany). Cyanobacterial suspension, culture liquid and extracts from it were similar in composition and quantity of organic substances and contained such compounds as phytoene, phytofluin, N-acetylglucosamine, peptidoglycan murein, lycopene, lutein, kauren (a precursor of gibberellin), vitamin A, provitamins, peptide borofitsin. The stimulating effect of N. paludosum exometabolites on linear growth of barley aboveground organs and roots mainly manifests itself in the first three days of their growth. Cyanobacterial exometabolites reduce the intensity of lipid peroxidation in plant cells, which indicates their antioxidant activity. Exometabolites of cyanobacterial suspension and hexane extract have a protective effect on plants, leveling the growth- inhibitory effect of copper (II) ions on the height of seedlings. The concentration of copper (II) ions was 3 mg / kg of the substrate for growing wheat. Cultivation of barley on cyanobacterial suspension and extraction of exometabolites with carbon tetrachloride results in the accumulation of peptide borofitsin in barley tissues in the amount of 0,0008–0,001 µg / g of dry weight.