Palynological analysis of Tripolium pannonicum on the littoral of the White Sea coast

The object of this study is Tripolium pannonicum - a halophyte growing on the western coast of the White Sea in the vicinity of the village Keret (Keretskaya Bay) and village Rastnavolok (Onega Bay). The data of palynological studies for the period 2014-2020 are summarized. The high degree of adaptability of this plant to the conditions of the sea coast makes it a convenient object for studying the mechanisms of salt tolerance, as well as for palynological studies, as the most informative about the viability of the population. The aim of the work is to study the state of pollen of T. pannonicum plants under different flooding conditions in the littoral. The study was carried out on the coast of the White Sea along transects, in sample plots within the natural boundaries of vegetation in the lower, middle, upper littoral and supralithoral. A total of 3 transects, up to 150 m long, were laid out. At least 16,000 pollen grains from 40 plants in 11 sample plots were analyzed. Pollen quality was assessed using the standard acetocarmine method. The pollen samples contained both normally formed grains and defective ones, which were combined into 7 groups. The lowest rates of normally formed pollen were noted in the conditions of the upper littoral of the village Keret - 82.9 ± 3.4 % and the village Rastnavolok - 86.6 ± 4.3 %, as well as in the lower littoral and supralittoral in the village Keret (77.0 ± 4.3 % and 82.7 ± 6.1 %, respectively). In the course of the study it was revealed that optimal conditions for the development of the T. pannonicum population are formed in the middle part of the littoral. A greater diversity of abnormal pollen was noted in the vicinity of the village Rastnavolok, in contrast to the village Keret. This fact as well as the absence of significant differences in the content of normally formed pollen in both Rastnavolok and Keret makes it possible to consider the range of teratamorphic pollen of 10-30 % as the reaction of the species in littoral conditions. The amount of normally formed pollen is sufficient to ensure a normal existence for the population due to seed propagation of plants.