Structure particularity of spring barley mycocenoses and properties of mushrooms from alienated radioactively contaminated territories of the Novozybkovsky district of the Bryansk region

Abstract

The features of the structure of mycocenoses of spring barley Gonar in the alienated territories of the Novozybkovsky district of the Bryansk region, contaminated with radionuclides as a result of the Chernobyl accident, have been studied. The study was carried out in 1991–1998 (pollution density 137Cs ~1.8 MBq/m2) using traditional field methods of observation and laboratory analyses to identify fungal species and determine their activity. 7 years after the accident, the epiphytic microbiota of barley seeds was characterized by increased activity of fungi from the genus Fusarium with the dominance of the causative agent of snow mold F. nivale Ces. (Microdochium nivale) and the mycotoxic fungus F. sporotrichiella Bilai. (sin. F. sporotrichioides). For comparison, at the same time, the microbiota of barley seeds in the fields of the Ramenskoye district of the Moscow region differed not only in the species composition of fungi, but also in their properties: the absence of such species of fungi as Nigrospora oryzae and Ulocladium con-sortiala, quite numerous in the Bryansk fields, and the presence of micro-roorganisms of the fungus F. sambucinum Fuckel, not found on polluted 137Cs and fields removed from economic turnover. There is also a noticeable presence of fungi from the genus Fusarium in the structure of the intra-seed infection of barley. The properties of metabolites of fungi from the genus Penicillium were determined: suspensions of fungal spores P. expansum and P. cyclopium used for processing barley seeds caused depression – a significant decrease in seed germination and morphophysiological characteristics of the development of seedlings. Isolates of 26 species of fungi were screened for their effect on the survival of paramecia and their rating was compiled. It is shown that in the absence of planned management of crop production by regional technologies and the use of plant protection products against diseases for 7 years after the accident, there was a shift in the structure of fungal species present on the roots and stems of barley of the Gonar variety towards an increase in the proportion of phytopathogenic fungi. With a large number of micromycete species on barley plants on radionuclide-contaminated fields of the Bryansk region and “clean” lands of the Moscow region (22 species versus 21, respectively), 9 species of phytopathogens (41% of the total number of species) and 7 species (33%) were isolated in technogenic territories. At the same time, the total activity of phytopathogens in the alienated radioactively contaminated territories was 18 points, in the “clean” ones – 13. Ratio of Phytopathogens/Saprophytes, calculated by the total activity of these groups of fungi, in the Bryansk region was 37.5% more than in the Moscow region, and by the ratio of Phytopath-genes/Antagonists – 2.2 times more. At the same time, the tendency of phytopathogens to prevail over other types of fungi in radioactively contaminated areas was natural, which was confirmed by the results of earlier studies.