ECOLOGICAL AND GEOCHEMICAL SPECIFICS OF SOIL AND PLANT COVERING OF URBAN LANDSCAPES (IN THE TOWN OF BROVARY AS AN EXAMPLE)

The results of the pollutants content research in urbanized landscapes soils of Ukraine (on the example of Brovary city, Kyiv region) were shown. The total and mobile contents data of chemical elements (Ni, Co, Zn, V, Pb, Cr, Cu) were obtained and analyzed using the methods of landscape-geochemical studies, analytical and statistical methods. The dependences of the vegetation resistance in cities to the level of soil cover contamination and the degree of heavy metals income have been established. The geochemical characteristics (such as the value of the accumulation coefficients; concentration of soil and vegetation cover; index of biogeochemical activity of the species within Brovary city) were analyzed. Throughout most of the city territory, the level of soil contamination is above average. Soils are characterized by the following association of heavy metals: Cu> Pb> Zn> Co> Cr> V> Mo> Mn> Ni. The dominant association is distributed heterogeneous throughout the city, forming geochemical anomalies depending on the source of contamination. The maximum technogenic load was recorded in urban soils areas within zones of transport infrastructure, production and communal-warehouse facilities.Woody vegetation is the most actively absorbed copper, manganese from the soil, and the least intensively absorbed chromium, vanadium and nickel. The biogeochemical activity coefficient of the research species is the following: Acer platanoides - 7,26, Betula pendula Roth. - 7,07, and Populus deltoides - 7,05, Pínus sylvestris - 1.32 and Alnus incana - 3.37. The biological absorption coefficients of manganese and copper are high because these metals have the ability to form strong complexes with organic matter. Biological absorption coefficients of vanadium and chromium is low for the researched plant species because these chemical elements are immobile in soils. For the city of Brovary, the presence of polyelemental contamination of soil and vegetation has been established. According to the indicators of the gross content of VM, the main pollutants are Cu, Zn, Pb and Mn. Concentrations of gross and mobile forms of VM exceed background values ​​and maximum concentration limits in 17-28 times. The maximum of man-caused load was recorded in the urban soils of the transport infrastructure zone and the zone of production and communal-warehouse facilities. Regularities of formation of elemental composition of plants of urban areas undergo significant changes in comparison with natural conditions, which is due to the strengthening of the role of foliar absorption of pollutants from the air and their high content in soils. The greatest ability to bioaccumulate has a male thyroid (Dryopteris filix-mas Schott) and birch (Convolvulus arvensis). The highest coefficient of biogeochemical activity of the studied species is Acer platanoides - 7.26, hanging birch (Betula pendula Roth.) - 7.07 and Canadian poplar (Populus deltoides) - 7.05, the lowest - Scots pine (Pínus sylvеstris ) - 1.32 and gray alder (Alnus incana) - 3.37. Weakly and very weakly, most of the studied plant species capture vanadium and chromium, which are relatively sedentary in the soil. Further research is needed to analyze the physicochemical parameters of soils, the coefficients of transition of metals to plants relative to their content in organic and mobile form in order to establish the relationships that characterize the process of translocation of chemical elements. Keywords: landscape-geochemical conditions, heavy metals, soils, vegetation.

Multivariate genome-wide association study of leaf shape in a Populus deltoides and P. simonii F1 pedigree

Leaf morphology exhibits tremendous diversity between and within species, and is likely related to adaptation to environmental factors. Most poplar species are of great economic and ecological values and their leaf morphology can be a good predictor for wood productivity and environment adaptation. It is important to understand the genetic mechanism behind variation in leaf shape. Although some initial efforts have been made to identify quantitative trait loci (QTLs) for poplar leaf traits, more effort needs to be expended to unravel the polygenic architecture of the complex traits of leaf shape. Here, we performed a genome-wide association analysis (GWAS) of poplar leaf shape traits in a randomized complete block design with clones from F1 hybrids of Populus deltoides and Populus simonii. A total of 35 SNPs were identified as significantly associated with the multiple traits of a moderate number of regular polar radii between the leaf centroid and its edge points, which could represent the leaf shape, based on a multivariate linear mixed model. In contrast, the univariate linear mixed model was applied as single leaf traits for GWAS, leading to genomic inflation; thus, no significant SNPs were detected for leaf length, measures of leaf width, leaf area, or the ratio of leaf length to leaf width under genomic control. Investigation of the candidate genes showed that most flanking regions of the significant leaf shape-associated SNPs harbored genes that were related to leaf growth and development and to the regulation of leaf morphology. The combined use of the traditional experimental design and the multivariate linear mixed model could greatly improve the power in GWAS because the multiple trait data from a large number of individuals with replicates of clones were incorporated into the statistical model. The results of this study will enhance the understanding of the genetic mechanism of leaf shape variation in Populus. In addition, a moderate number of regular leaf polar radii can largely represent the leaf shape and can be used for GWAS of such a complicated trait in Populus, instead of the higher-dimensional regular radius data that were previously considered to well represent leaf shape.

Inoculated Seed Endophytes Modify the Poplar Responses to Trace Elements in Polluted Soil

Seed endophyte inoculation can enhance the plant tolerance to pollutants, which allows plant cultivation on trace element (TE) polluted soils. Methylobacterium sp. CP3 and Kineococcus endophyticus CP19 were tested in vitro for their tolerance to Zn and Cd and their plant growth promotion traits. The in vivo effects of bioaugmentation with individual strains or both strains were tested using two poplar cultivars, Populus deltoides x (P. trichocarpa x P. maximowiczii) ‘Dender’ and ‘Marke’, grown in TE polluted soil for six weeks. Methylobacterium sp. was found to grow on media enriched with 0.4 and 0.8 mM Cd, and both endophytes tolerated 0.6 and 1 mM Zn, due to the presence of genes involved in Zn and Cd tolerance and transport. Methylobacterium sp. showed an extracellular ion sequestration mechanism. Production of indole-3-acetic acid by Methylobacterium sp. and K. endophyticus, as well as phosphorus solubilization by Methylobacterium sp. were observed. Bioaugmentation with both endophytes increased the shoot length of Populus ‘Marke’ and enhanced the Mg uptake in both cultivars. Inoculation with Methylobacterium sp. reduced the bioaccumulation of Zn in ‘Marke’, conferring it an excluder strategy. Methylobacterium sp. and K. endophyticus seemed to improve the plant nutritional status, which can alleviate abiotic stress.

CALIDAD DE PÉLETS A PARTIR DE BIOMASA DE OCHO ESPECIES DENDROENERGÉTICAS DE CRECIMIENTO RÁPIDO

La productividad de biomasa en especies de crecimiento rápido es una de las mejores alternativas para la elaboración de biocombustibles dendroenergéticos. Uno de los pretratamientos de la biomasa más importantes es el peletizado y con esto aumenta el poder calorífico. El objetivo de este estudio fue evaluar la calidad de pélets de ocho especies dendroenergéticas de crecimiento rápido. Las especies evaluadas fueron Eucalyptus globulus, Pinus greggii, Populus alba, Acacia retinoides, Ricinus communis, Populus deltoides, Pennisetum sp. y Salix sp. El diseño experimental fue completamente aleatorio; las especies analizadas como tratamientos. Con los datos se realizó un ANDEVA y las medias de los tratamientos se compararon con la prueba de Tukey (p≤0.05). Las variables evaluadas fueron: contenido de humedad (CH), cenizas, material volátil (CV), carbón fijo (CF) y poder calorífico superior (PCS); diámetro, longitud, peso, volumen, densidad a granel (DG) y densidad básica (DP); índice de resistencia, pérdida de biomasa y friabilidad (F). Las diferencias entre especies fueron significativas (p ≤0.05), para todas las variables. Ocho de las nueve especies cumplieron con valores mínimos del PCS (19.2 MJ kg-1 y 20.1 MJ kg-1) requerido en normas internacionales de calidad en pélets (18.0 MJ kg-1). Los pélets de ocho especies mostraron las dimensiones solicitadas en las normas de calidad. Todas las especies presentaron densidad aceptable, con base en la norma internacional. En la densidad básica se observaron valores altos y significativos en Pennisetum sp (1.4 g cm-3) y Pinus greggii (1.4 g cm-3), mientras que P. deltoides registró el valor más bajo (1.0 g cm-3). En las pruebas de resistencia, los pélets de P. greggii mostraron valores altos para el número de partes al rompimiento (2.4) y pérdida de biomasa (41.6%); así como valores bajos de friabilidad (0.45). Los pélets obtenidos a partir de la biomasa de las especies evaluadas cumplieron con los estándares internacionales de calidad.

Morphological, physiological, and transcriptional responses to low nitrogen stress in Populus deltoides Marsh. clones with contrasting nitrogen use efficiency

Background Nitrogen (N) is one of the main factors limiting the wood yield in poplar cultivation. Understanding the molecular mechanism of N utilization could play a guiding role in improving the nitrogen use efficiency (NUE) of poplar. Results In this study, three N-efficient genotypes (A1-A3) and three N-inefficient genotypes (C1-C3) of Populus deltoides were cultured under low N stress (5 μM NH4NO3) and normal N supply (750 μM NH4NO3). The dry matter mass, leaf morphology, and chlorophyll content of both genotypes decreased under N starvation. The low nitrogen adaptation coefficients of the leaves and stems biomass of group A were significantly higher than those of group C (p < 0.05). Interestingly, N starvation induced fine root growth in group A, but not in group C. Next, a detailed time-course analysis of enzyme activities and gene expression in leaves identified 2062 specifically differentially expressed genes (DEGs) in group A and 1118 in group C. Moreover, the sensitivity to N starvation of group A was weak, and DEGs related to hormone signal transduction and stimulus response played an important role in the low N response this group. Weighted gene co-expression network analysis identified genes related to membranes, catalytic activity, enzymatic activity, and response to stresses that might be critical for poplar’s adaption to N starvation and these genes participated in the negative regulation of various biological processes. Finally, ten influential hub genes and twelve transcription factors were identified in the response to N starvation. Among them, four hub genes were related to programmed cell death and the defense response, and PodelWRKY18, with high connectivity, was involved in plant signal transduction. The expression of hub genes increased gradually with the extension of low N stress time, and the expression changes in group A were more obvious than those in group C. Conclusions Under N starvation, group A showed stronger adaptability and better NUE than group C in terms of morphology and physiology. The discovery of hub genes and transcription factors might provide new information for the analysis of the molecular mechanism of NUE and its improvement in poplar.

Morpho-Physiological and Biochemical Changes in Syzygium cumini and Populus deltoides: A Case Study on Young Saplings under Water Stress

Drought is one of the most devastating climate factors in terms of its spatial extent and intensity. Therefore, a study was conducted to evaluate the water stress tolerance in young saplings of Syzygium cumini (L.) Skeels and Populus deltoides Marchall that are cultivated in the rain fed areas of Pakistan. Plants were subjected to three levels of moisture regimes: well-watered (WW, 90% of field capacity), mild stress (MS, 60% field capacity), and severe stress (SS, 30% of field capacity). Results showed that dry biomass production (leaf, stem, and root), chlorophyll a, b and carotenoid contents decreased significantly while osmolyte accumulation increased in both species, with the highest increase was evidenced in Populus deltoides saplings. A significant decrease was evidenced in CO2 assimilation rate and stomatal conductance that resulted in a significant increase in intrinsic water use efficiency in both species under MS and SS. In both the species, along with a significant increase in the production of hydrogen peroxide and superoxide radical, the antioxidants enzyme activities of superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase also increased significantly in both species under MS and SS with highest activity evidenced in Syzygium cumini. The results suggest that Syzygium cumini saplings showed better a tolerance mechanism to water stress.

Analysis of allergen components and identification of bioactivity of HSP70 in pollen of Populus deltoides

Background Allergies caused by pollen from Populus deltoides are common, but the allergic components are still unclear. Methods The total proteins in pollen of P. deltoides were analyzed by proteomics, and the potential allergens were identified via the WHO/IUIS database and the allergenOnline database retrieval. One target protein was screened by bioinformatics and expressed in Escherichia coli. The biological activity of the expressed product was verified by animal experiments. Results The total of 3929 proteins in pollen of P. deltoides were identified, and 46 potential allergens belonging to 10 protein families were recognized by database retrieval. B9N9W6 protein of Hsp70 family was screened by bioinformatics analysis and expressed successfully. ELISA showed that B9N9W6 can stimulate the immune system to produce specific IgE and promote the generation of IL-4. Flow cytometry showed that B9N9W6 can significantly stimulate the proliferation of CD4+ T cells and promote the polarization of Th2 cells. The pathological sections of mice lung tissues indicated that alveolar destruction was more severe in the B9N9W6 group than that of extract group, and there were more inflammatory cells infiltration, mucus exudation and bleeding. Conclusion B9N9W6 is an important antigenic substance in the pollen of P. deltoides. Due to the conserved structure of Hsp70 family, more attention should be paid to the possibility of sensitization when Hsp70 from any pathogenic species is administered.