Differentiation of Dust Holding Capacity of Poplar Crowns

One of the key parameters of comfort and compliance with sanitary standards for cities is dustiness of atmosphere. Plantings of representatives of the poplar genus (Populus L.) become a reliable means of optimizing this parameter. We have studied the effectiveness of using different types of poplars in urban plantings, taking into account the differentiation of crown sections by the ability to deposit dust on the surface of the leaf apparatus. The object of research is 8 species from different sections of the poplar genus, typically found in urban plantings of the Nizhny Novgorod region. We considered the influence of three independently of one another factors on the dispersion of dust holding capacity: species-specificity of poplars (8 gradations); lighting conditions of crown due to its orientation relative to the cardinal directions (4 gradations); height characteristics of the crown tier location (3 gradations). Dust was washed off from 100 leaves of each poplar species with their fixed area. The highest amount of dust in the flushes was observed for silver poplar (257.60±5.05 mg), and the lowest – for black poplar (117.69±3.65 mg) and Pópulus nígra var. itálica (105.69±2.90 mg). Oneway ANOVA confirmed the significance of differences between the species for all parameters of dust holding capacity. Three-way ANOVA showed the influence of leaf surface locations in different parts of the crown on the efficiency of dust deposition by representatives of different species. Species appeared to be the most important in the distribution of dust deposited on the leaf surface of shoots in different parts of the crown; the share of its influence was 37.65±0.51 %. The effect of crown lighting conditions was also well measurable; its share was equal to 20.45±0.28 %. The influence of the crown tier height was noticeably less; its share reached 7.19±0.21 %. The listed factors are little related to each other, and their interaction generated a negligible effect: 6.67±4.54 %, Fh2 = 1.47, significance is reliable at 5 % level (F05 = 1.41) and unreliable at 1 % level (F01 = 1.61). For citation: Besschetnova N.N., Besschetnov P.V. Differentiation of Dust Holding Capacity of Poplar Crowns. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 5, pp. 48–64. DOI: 10.37482/0536-1036-2021-5-48-64

Antimicrobial Activity, In Vitro Anticancer Effect (MCF7 Breast Cancer Cell Line), Antiangiogenic and Immunomodulatory Potentials of Populus Nigra L. Buds Extract

Purpose: The aim of this study was to evaluate the antioxidant potential, antimicrobial activity, the in vitro anticancer effect (MCF7 breast cancer cell line), as well as the antiangiogenic and immunomodulatory potential of Populus nigra L. bud (Pg) extract collected from the western part of Romania.Results:Populus nigra L. bud extract presents an important antioxidant activity, due to the rich phytochemical composition. Regarding the biological activity, results have shown that poplar bud extract presents a significant inhibitory activity against Gram-positive bacteria and a dose-dependent decrease of MCF7 tumor cell viability with an IC50 of 66.26 µg/mL, while not affecting healthy cells. Phenomena of early apoptotic events at the maximum concentration tested (150 µg/mL) were detected by Annexin V-PI double staining. The extract induced G0/G1 phase cell cycle arrest. In addition, Pg extract showed antiangiogenic potential on the chorioallantoic membrane. Also, at the highest concentration (150 µg/mL), good tolerability and no signs of toxicity upon vascular plexus were observed. Moreover, in low concentrations, the Pg extract had immunomodulatory activity on primary human dendritic cells by upregulating IL-12 and IL-23 subunits.Conclusion:The study concludes that poplar bud extract elicited antioxidant activity, antitumor properties on the breast cancer cell line, followed by an antiangiogenic effect and an immunomodulatory potential on human primary dendritic cells. The biological activity of Populus nigra L. buds extract may open new directions of research on the topic addressed.

Influence of drought and salt stress on the growth of young Populus nigra ‘Italica’ plants and associated mycorrhizal fungi and non-mycorrhizal fungal endophytes

Populus nigra ‘Italica’ (Lombardy poplar) is a breeding cultivar of black poplar, widely used as a street tree or windbreak, often exposed to salinity and limited water availability. Populus roots can develop dual mycorrhizal associations with ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) fungi, and with non-mycorrhizal fungal endophytes (FE). The symbiotic fungi may alleviate the effects of adverse environmental conditions. We investigated the performance (growth and symbiotic associations) of one-year-old Populus nigra ‘Italica’ grown from woody cuttings in soil from natural poplar habitat and subjected to water scarcity and soil salinity (50 mM NaCl, 150 mM NaCl, 250 mM NaCl). With increasing soil salinity, a decrease in the growth parameters of the aboveground parts of the poplar plantlets and their fine roots were found; however, the roots were more resistant to the stress factors analyzed than the shoots. ECMF, AMF, and non-mycorrhizal FE were all tolerant to increased salt levels in the soil, and the ECM abundance was significantly higher under conditions of mild salinity (50 mM NaCl, 150 mM NaCl) compared to the control plants and those treated with 250 mM NaCl. Our results indicated that enhanced soil salinity increased the content of sodium and chlorine in leaves, but did not affect significantly the concentrations potassium, magnesium, calcium, phosphorus, or nitrogen. Significant accumulation of proline in leaves suggest salt stress of P. nigra ‘Italica’ treated with 250 mM NaCl and contribution of proline to the plant defense reactions.

Variation in morphological and wood cell traits in coppice stems of Populus nigra L. and Salix alba L.

Coppice management is an ecologically important silvicultural practice to provide the quicker and higher potential of wood biomass production for industrial demands. Understanding morphological and anatomical responses of coppiced trees could help to determine the quantity and quality of wood and thus provide better management of coppiced tree plantations for short-time biomass production. However, there is a little investigation in morphological and anatomical adaptation in different fast-growing tree species. The present study, therefore, studied how morphology and anatomy vary between two fast-growing coppices of Populus nigra L. (black poplar) and Salix alba L. (white willow). Each coppiced tree was grown in a similar habitat and was at a similar age. However, each coppiced tree showed different morphological and anatomical plasticity in their stems in response to environmental factors. Poplar coppices showed better anatomical properties due to greater vessel diameter, fibre length, fibre width, fibre wall thickness, and ray height; however willow coppices had better morphological plasticity which had higher average stem height and ring width. The results suggest that willow coppices had the greater height growth potential even at 2 years of age than poplar coppices.

The Phytochemical Study of the Populus nigra L. Leaves

From the leaves of the black poplar (Populus nigra L., Salicaceae family) there were for the first time isolated rutin (quercetin-3-O-rutinoside), calendoflavobioside (quercetin-3-O-neohesperidoside) (flavonoids) and ferulic acid (phenylpropanoid) by using of liquid column chromatography. The chemical structures of the isolated compounds there were elucidated by means of 1H-NMR-, 13C-NMR-, UV-spectroscopy, mass spectrometry and results of chemical transformations. The isolated flavonoids are the dominant phenolic components of the raw material of the investigated plant. It was determined, that the isolated flavonoids cause the spectral characteristics of the UV spectra of the water-ethanolic extract from the Populus nigra leaves. It was substantiated the expediency of the estimation of the total flavonoids in the leaves of Populus nigra calculated on rutin. As results there was development the method of the quantitative determination of the total flavonoids in the leaves of Populus nigra by the using of the differential spectrophotometry at an analytical wavelength of 414 nm. It was determined that the content of the total flavonoids in the raw materials of the studied plant varies from 2.04±0.09% to 2.99±0.11%. The relative degree of the determination of the total flavonoids in the leaves of black poplar in developed method with confidence probability 0.95 is no more than ± 6.26%.