Биология

Due to the small number of studies on the role of coumarins in associative symbiotic relationships, some aspects of the infl uence of synthetic coumarins on the physicochemical and cultural properties of Azospirillum baldaniorum Sp245 were studied for the fi rst time. To reveal the role of hydroxylation in position 7 of the fused aromatic ring – 1-(2-oxo-2H-chromen-3-yl)butan-1,3-dione, comparative studies of the eff ect of the original and hydroxylated coumarins on the culture of a model strain of azospirilla were carried out.

Arylidenisoxazolones have been known since the second half of the 20th century and still retain their relevance as biologically active compounds and the basis for further transformations.

The article presents the results of processing funds stored in the herbarium of the Saratov State University (SARAT), belonging to the Iridaceae family. The Herbarium of SSU (SARAT) was founded in 1909; at present, signifi cant material has been accumulated, which has not yet been fully processed. The Iridaceae family contains a number of species that are subject to protection, including at the federal level. It is quite large (more than 60 genera and 800 species distributed throughout the globe).

The Volgograd reservoir is a highly complex hydrological system. The locations of fi sh watering holes, which are situated in an abyssal area of the Volgograd reservoir, have been well established for a long time. Meanwhile, fi sh watering holes exist in areas of the bed of the Volgograd reservoir as well. However, their determination is not always possible and is complicated due to the small size and shallow depth of the watering holes.

The article presents the results of studying the combination ability of new dihaploid maize lines created by diploidization of haploid plants obtained using a haploinducer line. The experiment involved simple hybrids (30 combinations) obtained according to the complete diallel scheme of 6 homozygous lines. The eff ects of GCA and variance of SCA lines, as well as the components of genetic variance in terms of the main morphometric parameters of the plant (stem length, ear height, panicle length, stem diameter, plant leaf surface area) were revealed.

The article presents the results of a long-term introduction of Tulipa sylvestris L. in the SB RAS Central Botanical Garden collection. Plants of the species T. sylvestris bloom abundantly and have a reproductive factor of 1–2 for the daughter bulbs. It was found that the short phase of fl owering is characterized by smooth temperature changes, the most dramatic for a long period. We also established a direct dependence of the duration of the fl owering period on the amount of precipitation during this period, the correlation coeffi cient was 0,7.

The results of a parasitological study of uninhabited nests of the common vole Microtus arvalis s.l., collected on territory of the Dukhovnitsky district of the Saratov Region in April 2019 are presented. We identifi ed nine species of gamasid mites associated with nests of the common vole. For the fi rst time, Laelaps algericus Hirst., 1925, was recorded for the fauna of the Dukhovnitsky district of the Saratov Region. We found two new to Saratov region genera of free-living mites (without species identifi cation): Laelaspis A.