Материалы к флоре болот Тамбовской области

Тамбовская область находится в лесостепной природной зоне, которая характеризуется сравнительно низкой заболоченностью и сильным преобразованием естественных ландшафтов. В XX веке болота подверглись значительному антропогенному воздействию, что отразилось на флоре, но почти не было зафиксировано в публикациях последних трех десятилетий. Нами в 2011–2021 гг. маршрутно-ключевым методом обследовано 46 болот в 13 районах Тамбовской области, на основе полученных результатов составлен список высших растений, указано их распределение по основным типам болот (низинные, переходные, верховые) и встречаемость. На болотах Тамбовской области выявлено 158 видов сосудистых растений (108 родов и 55 семейств) и 33 вида мхов (14 родов и 9 семейств). Наиболее часто на болотах региона из сосудистых растений встречались Salix cinerea, Typha latifolia, Lysimachia vulgaris, L. thyrsiflora, Carex acuta, Betula pubescens, Calamagrostis canescens, Phragmites australis, Lycopus europaeus, из мхов – Sphagnum fallax, S. flexuosum, S. angustifolium. На болотах зафиксированы популяции 22 видов, включённых в Красную книгу Тамбовской области. БлагодарностиРабота проведена в рамках выполнения государственного задания 121051100099-5.

Secondary metabolites of downy birch buds (Betula pubescens Erch.)

The subject of this study is the composition of low-molecular-weight metabolites in downy birch (Betula pubescens) buds and their participation in protection from various kinds of stress. Using the GC-MS, 640 compounds were detected, of which 314 were identified in downy birch buds for the first time. The volatile components detected using the SPME technique mainly consisted (about 70% of the total ionic current of the chromatogram, TIC) of mixtures of sesquiterpenoids. The exudate covering the buds, along with sesquiterpenoids (approximately 60% of TIC), included flavonoids (25% of TIC). The main part of the material extracted by supercritical carbon dioxide from buds comprised sesquiterpenoids and triterpenoids (47 and 28% of TIC, respectively). Via column chromatography, 25 known compounds (mainly flavonoids and triterpenoids) were isolated, most of which were first discovered in the buds of downy birch. Many compounds of these classes have strong biological activity and probably either directly or indirectly perform a protective function in birch buds. An assumption is made about the biological role of a number of secondary metabolites (such as volatile isomeric megastigmatriens and triterpene seco-acids) as well as about these compounds’ possible means of biosynthesis, which were first discovered in the buds of downy birch.

Electricity consumption of drying and the effect of the dryer and temperature on the chemical quality of nettle leaves (Urtica dioica L.), birch leaves (Betula pendula, Betula pubescens) and roseroot (Rhodiola rosea L.)

Drying can constitute the majority of the energy costs and thus, manufacturing costs, in plant refining. The use of higher drying temperatures accelerates drying and reduces total electricity consumption. However, higher drying temperatures can also reduce the chemical quality of plants, as heat sensitive compounds can degrade or evaporate. The purpose of the study was to find the optimum drying temperature for nettle leaves (Urtica dioica L.), white and silver birch leaves (Betula pubescens, Betula pendula) and roseroot (Rhodiola rosea L.) in terms of electricity consumption and quality. Selected plants were dried with drying oven, convective dryer and vacuum dryer between 40 and 80 °C. The quality was determined by measuring total polyphenol content, antioxidant capacity and active compounds of roseroot. The lowest total electricity consumption was obtained by drying oven, but the highest chemical quality was obtained by vacuum dryer. The optimum drying temperature varied between 65 and 80 °C.

Identification and taxonomy of Betula (Betulaceae) in Great Britain and Ireland

Floras and identification guides typically do not list the full range of identification features that discriminate between Betula pendula Roth and B. pubescens Ehrh., and some accounts contain errors. Discriminatory identification features are described and illustrated. Introgression from the diploid, B. pendula into B. pubescens is widespread. It also occurs from B. nana L. into B. pubescens, but obviously introgressed examples of the latter are probably rare. Betula pubescens presents the greatest unresolved identification difficulties. Trees identified as B. pubescens subsp. celtiberica (Rothm. & Vasc.) Rivas Mart., particularly in Wales, may be part of the variation within British B. pubescens, due to introgression from B. pendula. The most widespread of the small-leaved forms of B. pubescens is correctly named var. fragrans Ashburner & McAll. Several misapplied names have been given to this taxon, most recently subsp. tortuosa (Ledeb.) Nyman, which does not occur in Europe. Not all small-leaved B. pubescens are var. fragrans; some examples show clear signs of introgression from B. nana, and may be referable to the northern var. pumila (L.) Govaerts.

Seasonal and elevational variability in the induction of specialized compounds from mountain birch (Betula pubescens var. pumila) by winter moth larvae (Operophtera brumata)

The mountain birch (Betula pubescens var. pumila (L.)) forest in the Subarctic is periodically exposed to insect outbreaks, which are expected to intensify due to climate change. To mitigate abiotic and biotic stresses, plants have evolved chemical defenses, including volatile organic compounds (VOCs) and non-volatile specialized compounds (NVSCs). Constitutive and induced production of these compounds, however, are poorly studied in Subarctic populations of mountain birch. Here, we assessed the joint effects of insect herbivory, elevation, and season on foliar VOC emissions and NVSC contents of mountain birch. VOCs were sampled in situ by an enclosure technique and analyzed by gas chromatography–mass spectrometry. NVSCs were analyzed by liquid chromatography–mass spectrometry using an untargeted approach. At low elevation, experimental herbivory by winter moth larvae (Operophtera brumata) increased emissions of monoterpenes and homoterpenes over the three-week feeding period, and sesquiterpenes and green leaf volatile in the end of the feeding period. At high elevation, however, herbivory augmented only homoterpene emissions. The more pronounced herbivory effects at low elevation were likely due to higher herbivory intensity. Of the individual compounds, linalool, ocimene, 4,8-dimethylnona-1,3,7-triene, 2-methyl butanenitrile, and benzyl nitrile were among the most responsive compounds in herbivory treatments. Herbivory also altered foliar NVSC profiles at both low and high elevations, with the most responsive compounds likely belonging to fatty acyl glycosides and terpene glycosides. Additionally, VOC emissions from non-infested branches were higher at high than low elevation, particularly during the early season, which was mainly driven by phenological differences. VOC emissions varied substantially over the season, largely reflecting the seasonal variations in temperature and light levels. Our results suggest that if insect herbivory pressure continues to rise in the mountain birch forest with ongoing climate change, it will significantly increase VOC emissions with important consequences for local trophic interactions and climate.