Vol 109, No 7 (2024)

Renewal buds are a good model for studying growth, metabolism and bioenergetics under the influence of environmental factors (light, temperature). Such studies can provide new information about physiological, biochemical and molecular mechanisms of shoot growth at the stage of growth inside the bud under the influence of exogenous and endogenous factors. The paper contains the data on seasonal changes in energy metabolism, fractional composition of water, content of photosynthetic pigments, soluble carbohydrates, protein, and fatty acids in renewal buds of Hylotelephium triphyllum (Haw.) Holub. In the renewal buds formed in August, the total water content is about 85%, the share of water passing into the crystalline state – more than 90%, the temperature of the water-to-ice phase transition – −6°C. The intensity of respiration decreases, and the rate of energy storage, accumulation of soluble carbohydrates and unsaturated fatty acids increases gradually against the high water content and high proportion of unbounded water in plant tissues as long as the average daily temperatures decrease. There is a direct relationship between the respiration intensity, heat release, and energy storage. During the autumn-winter-spring period, the proportion of stored energy from the energy produced by respiration is about 40%. The formation of the photosynthetic apparatus of renewal buds is accompanied by a decrease in the rate of heat release and in the amount of stored energy. The swelling of buds proceeds simultaneously with an increase in the content of fatty acids, which indicates the activation their synthesis and coincides with the spring maximum content of chlorophylls and carotenoids. At this period, the total water content is about 75%, the proportion of water passing into the crystalline state – about 99%.

The temperature of the water-to-ice phase transition is −4.7°C. This temperature value of ice formation is probably the minimum possible temperature at which irreversible damages to cellular structures occur in renewal buds. Consequently, the high water saturation in renewal buds of Hylotelephium triphyllum maintains metabolic processes and, as a result, favors the implementation of morphophysiological and structural rearrangements in them but also significantly increases the risk of damage by negative temperatures in low-snow winters.

A comparative analysis of the development of anther and pollen grain in 6 species of the genus Dioscorea L. from the section Stenophora Uline (D. villosa, D. tokoro, D. nipponica, D. deltoidea, D. caucasica, D. balcanica) revealed common and individual characteristics in the species. It is shown that the species are characterized by the simultaneous microsporogenesis, and the tetrahedral tetrads. In D. villosa, D. nipponica and D. deltoidea the isobilateral type of tetrads was also found. The structure of the formed and mature anther walls is similar among the species. Based on the aggregate of individual structural features and duration of the tapetum functioning, the time of appearance of reserve substances in the pollen grain, the studied species are subdivided into 2 groups: 1) D. caucasica, and D. balcanica with an earlier (before meiosis of microsporocytes) start of the development of large 3–4-nucleated tapetum cells and a shorter period of their functioning (up to the stage of a highly vacuolated microspore), as well as with an earlier time of accumulation of reserve substances in the pollen grain, namely at the time of completion of mitotic division of the nucleus; 2) D. villosa, D. tokoro, D. nipponica, and D. deltoidea with 2-nucleated tapetum cells, short (D. villosa, D. tokoro) and long (D. nipponica, D. deltoidea) periods of its functioning, and with a later onset of accumulation of reserve substances in the pollen grain – at the time of movement of the generative cell inside the vegetative one. Pollen grains in all the species are monosulcate, 2-celled, with a well-developed exine and 2-layer intine in the area of the open aperture.

Andromonoecy was described and anthecological features were identified for the first time in Dorema microcarpum, a perennial monocarpic plant endemic to the Western Tien Shan and Northern Pamir-Alai. The research was carried out in the natural conditions of the Chust-Pap adyrs of the Fergana Valley in 2021–2023. The floral unit is shown to be an open tiered raceme of tiered racemes of simple umbels. In powerfully developed plants, paracladia are formed in the lower part of the synflorescence. The duration of flowering of an individual is 10–15 days. Simple umbels in different parts of the synflorescence can form only perfect flowers, or perfect and staminate flowers, or only staminate flowers. In poorly developed plants, simple umbels of lateral racemes from the 6th node form perfect flowers and 1 to 5 staminate flowers; simple umbels of 2–3 lower lateral racemes form only staminate flowers. In powerfully developed plants in the middle and upper parts of synflorescence, almost all simple umbels form only perfect flowers; staminate flowers are observed only on paracladia. The flowering of an individual begins with simple umbels on the lateral racemes located in the middle floral unit, namely from the 6th to the 9th nodes and occurs divergently: first, the middle and upper parts of the synflorescence completely fade, then the staminate flowers open on the lateral racemes of the lower parts (from the 3rd to the 5th nodes). The opening of flowers on lateral racemes occurs acropetally, and within simple umbels centripetally. D. microcarpum is a plant with a morning flowering rhythm: the opening of flowers begins early in the morning (about 5–6 a. m.) and continues until 9–10 a. m. Perfect flowers are characterized by strictly pronounced protandry. The flowering time of a perfect flower is 3–4 days, of a staminate flower – 1 day. The flowers are mainly visited by insects of two orders, Hymenoptera and Diptera. The presence of both perfect and staminate flowers, different times of their maturation and a strict synchrony of flowering of the perfect flowers of upper lateral racemes contribute to geitonogamy and also ensure cross-pollination of other individuals. Staminate flowers of lower lateral racemes or paracladia provide cross-pollination between individuals in different flowering phases.

The results of studying the chromosome numbers of 4 species from 3 genera of the family Lamiaceae from the Republic of Khakasia are presented. The material was collected in 2022 in six populations. The species Thymus petraeus (2n = 20) was studied for the first time. The chromosome numbers were determined in Dracocephalum discolor (2n = 12), Nepeta multifida (2n = 12), and Nepeta sibirica (2n = 18) for the first time from the territory of Khakasia. The range of distribution and published data on chromosome numbers are cited for each species. All the studied species are diploids.

The findings of two vascular plant species new to the Magadan Region and the north of the Russian Far East (Arctostaphylos uva-ursi (L.) Spreng., Cypripedium calceolus L.), new localities of Triglochin maritima L., and a new locality of a rare liverwort species (Bucegia romanica Radian) in the Chersky National Park are reported. The Omulevsky cluster of the national park is interesting for its calcareous flora, which is supplemented by findings of Cypripedium calceolus and Bucegia romanica. These species are protected at the federal level. The genus Arctostaphylos is new to the Magadan Region. The isolated locality of Arctostaphylos uva-ursi in the Omulevskaya Lowland is the easternmost in Eurasia, located 600–760 km or more from the nearest known localities in the Republic of Sakha (Yakutia) and Khabarovsk Territory. In the southern part of the Chersky Ridge, Triglochin maritima was known earlier from the herbarium specimens collected near Darpir Lake located in the Republic of Sakha (Yakutia).