Vol 108, No 6 (2023)

The genesis of the bicarpellate syncarpous gynoecium was analysed in Symphytum asperum in relation to the septa formation in it, which determines the structure of erems (a dispersal unit of schizogenetic fruits forming as a result of dividing each carpel of syncarpous gynoecium into two independent parts) and the coenobium as a whole. In the gynoecium, at early stages of development, a short fertile synascidiate zone arises due to the formation of a basal septum (septum of 1st type) at the fusing of the involute carpel edges. A symplicate zone is formed above. A double U-shaped synplacenta appears at the gynoecium base. The structure of the basal septum is characterized by some features. The sutures that form the septum are obsagittate, with their wide part directed towards the center, and their narrow part directed outward. The septum of the 1st type is characterized by a 4-rayed structure, resembling an elongated rhombus or 2 tetrahedral pyramids facing each other: short rays are located between the walls of emerging erems of the same carpel, and long rays are between the walls of the erems of adjacent carpels. The central part of the septum subsequently stops developing, and the rays are transformed into branches of syncarpous sutures (2 in each carpel), to form 4 septa of the 2nd type. The length of the septa of the 2nd type increases longitudinally. In the wall of the ovary on the dorsal side in the area of the vascular bundle, 4 strands of small thin-walled cells are formed. Then, a splitting of these strands and the dorsal vascular bundle in half takes place. The septa of the 2nd type, like curtains or inserts, connect open ventral margins with dorsal halves of the ovary wall in each carpel, later becoming part of the pericarp of single-celled erems. At the same time, the symplicate zone is divided into 4 independent compartments. In S. asperum, septa of the 2nd type do not divide the loculi of carpels into 2 compartments and are not united into single partitions. They remain autonomous, growing between open edges of the halves in each carpel. The resulting diaspores (erems) are surrounded by a fruit coat on all sides. The outgrowths are not detected between the erems. This growth of the septa of the 2nd type is unique and correlates with the growth of the gynobasic style, while the shape of the growing septa ideally coincides with the shape of its faces.

The scanning electron microscopy study of phytoplankton, phytoperiphyton and microphytobenthos has revealed 208 taxa of Bacillariophyta of specific and intraspecific ranks in Pizanets Lake. Among them, 66 species and varieties are new to the flora of Karelia, including 8 ones new to the flora of Russia. Some algae (13) are identified only to the genus. An ecological assessment of the species composition in relation to the characteristics of the environment is carried out.

The article analyzes distribution of 94 species of aquatic plants in 18 lakes, different in size, origin, trophic status, hydrological and hydrochemical conditions. Macrophytes and their communities were studied in 11 large and small lakes in the Kenozersky National Park, in 2 large lakes in the Onezhskoye Pomorye National Park, and in 5 small lakes in the Pinezhsky State Nature Reserve. The eutrophic lake Porzhenskoye in the Kenozersky National Park stands out with the greatest species number, 52 species. Fewer species of macrophytes were identified in oligotrophic lakes. It is shown that the majority of aquatic plants of the Arkhangelsk Region inhabit narrow range from low to medium total dissolved solids – 54 species. Eurybiont species, occurring in a large range of total dissolved solids from 1 to 1020 mg/l, show a great species diversity – 24 species. Only 11 species tend to grow in karst lakes with elevated level of total dissolved solids from 500 to 1020 mg/l – vascular plants: Ranunculus kauffmannii, Eleocharis acicularis, E. quinqueflora, Myriophyllum verticillatum, Potamogeton obtusifolius, Stuckenia pectinata, Sparganium hyperboreum; mosses: Calliergon cordifolium, Scorpidium scorpioides; algae: Chara aspera, C. subspinosa. The majority of species in the lakes of specially protected natural areas of the Arkhangelsk Region, growing in a narrow water pH range, are neutrophytes – 31 and neutro-alkalophytes – 27. Thirteen protected species of macrophytes were discovered in the flora of lakes in the Arkhangelsk Region – Chara aspera, C. strigosa, C. subspinosa, C. virgata, Fissidens fontanus, Fontinalis dalecarlica, F. hypnoides, Isoëtes echinospora, I. lacustris, Lobelia dortmanna, Nymphaea candida, N. tetragona, Sparganium gramineum.

23 species new to the lichen flora of the Kerzhenskiy Reserve are recorded based on the authors’ field research in 2022. 17 species and 4 genera (Icmadophila, Intralichen, Lichenostigma, Vezdaea) are new to the Nizhny Novgorod Region. Among them, Arthonia calcicola is reported for the first time for the European Russia, and Biatora fallax is new to the Central European Russia. The information about the localities, ecology and distribution of mentioned species is provided.

In modern botanical studies, various molecular genetic methods such as genome sequencing, PCR, AFLP-analysis, etc. are often involved. These methods require the use of high-quality (i.e. well purified and non-degraded) genomic DNA. However, extraction of such DNA from plants is complicated by a wide spectrum of organic compounds that contaminate DNA and drastically reduce its quality. As a result, the protocols for DNA extraction from plants are usually labor-intensive, time-consuming and require expensive reagents, most of which are imported from abroad. In the case of high-throughput DNA extraction from plant material, these disadvantages are of a great importance, especially in view of the current import problems. Moreover, there is no universal protocol suitable for all plant species and all variants of plant material used: different protocols are effective in different cases and additional modifications are often required. Promising ways to overcome these problems include the search for simplified methods of plant DNA extraction, as well as the use of specially prepared initial material.