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%.

Trunks of multi-stem black poplars may have different genotypes – evidence from the Oder valley in Poland

The black poplar (Populus nigra L.) is an ecologically and economically important tree species, characteristic for floodplain forests in Europe. It is now considered to be endangered in many European countries due to the loss of its natural habitat caused by the development of river engineering and intensive land use management of riverside areas. Multi-stem specimens can be found occasionally in natural black poplar populations. The percentage of such individuals is low, although in some stands it may be over a dozen percent. The origin of multi-stem trees may be different. As a consequence, trunks being part of such a tree can have the same or different genotypes. The study aimed to find out whether all trunks of multi-stem black poplars are ramets of the same genet or if their genotypes are different, in which case they increase the gene pool of the population. We used 13 microsatellite nuclear markers to analyze the genotypes of 83 trunks belonging to 34 multi-stem black poplar trees from five natural populations from the Oder river valley in Poland. We also performed the sibship analysis of all trunks. The results showed that the trunks being part of the particular individual had distinct genotypes in five trees (14.7%). This indicates that they were formed as a result of the fusion of two genetically different individuals. The sibship analysis revealed that one multi-stem tree was represented by full-sibs. In the remaining four trees the fused trunks were not related. Nevertheless, we found three pairs of half-sibs between different trees that were distant from each other. The majority of the multi-stem trees we examined developed most probably due to the damage to the apical meristem of the main shoot of a single-stem tree. Nevertheless, some of them were indeed formed from two distinct individuals. Therefore, if a particular population consists of a small number of individuals, we recommend to study the genotypic homogeneity of each multi-stem tree.

Volatile emission and biosynthesis in endophytic fungi colonizing black poplar leaves

Plant volatiles play a major role in plant–insect interactions as defense compounds or attractants for insect herbivores. Recent studies have shown that endophytic fungi are also able to produce volatiles and this raises the question of whether these fungal volatiles influence plant–insect interactions. Here, we qualitatively investigated the volatiles released from 13 endophytic fungal species isolated from leaves of mature black poplar (Populus nigra) trees. The volatile blends of these endophytes grown on agar medium consist of typical fungal compounds, including aliphatic alcohols, ketones and esters, the aromatic alcohol 2-phenylethanol and various sesquiterpenes. Some of the compounds were previously reported as constituents of the poplar volatile blend. For one endophyte, a species of Cladosporium, we isolated and characterized two sesquiterpene synthases that can produce a number of mono- and sesquiterpenes like (E)-β-ocimene and (E)-β-caryophyllene, compounds that are dominant components of the herbivore-induced volatile bouquet of black poplar trees. As several of the fungus-derived volatiles like 2-phenylethanol, 3-methyl-1-butanol and the sesquiterpene (E)-β-caryophyllene, are known to play a role in direct and indirect plant defense, the emission of volatiles from endophytic microbial species should be considered in future studies investigating tree-insect interactions.

Analyses of Microstructure and Dynamic Deposition of Cell Wall Components in Xylem Provide Insights into Differences between Two Black Poplar Cultivars

The chemical composition of the cell wall varies between species and even within the same species, and impacts the properties of the cell wall. In this study, the dynamic chemical compositions of the xylem cell walls of two black poplar cultivars, Populus × euramericana ‘Zhonglin46’ and Populus × euramericana ‘Neva,’ were investigated in situ using stimulated Raman scattering microscopy (SRS). Meanwhile, the pectin structural features were examined using immunofluorescence methods. The results showed that Neva displayed faster thickening of the fiber cell walls than Zhonglin46 did, and it had a greater cell wall thickness in mature xylem. A faster deposition speed of lignin and cellulose during xylem maturation was revealed in Neva. Significantly higher lignin contents were found in the mature xylem of Neva compared with those of Zhonglin46, while no obvious differences in cellulose deposition in mature xylem were observed between the two cultivars. The patterns of pectin deposition during xylem maturation were similar in the two cultivars, but more pectin was found in the mature xylem of Neva than in that of Zhonglin46. The chemical deposition patterns account for the anatomical feature differences between the cultivars. These results provide valuable insights into the chemical deposition and anatomical differences between cultivars, and they might be helpful in understanding the wood growth processes and facilitating the utilization of different poplar cultivars.

Impact of substrate supplemented with CaCO3 on mycelial growth, yield, morphological features and storability of fruiting bodies of black poplar mushroom Agrocybe cylindracea (DC.) Marie.

Black poplar mushroom, Agrocybe cylindracea deserves special attention, due to its medicinal properties. Water and alcohol extracts from fruiting bodies of the fungus have an anti-oxidant, anti-cancer, anti-fungal, cholesterol and triglycerides blood level lowering abilities. This mushroom is rich in proteins and vitamins, mineral elements and low in fat. The aim of the experiments was to determine effect of a substrate supplementation with CaCO3 on mycelial growth, yield, morphological features and storability of fruiting bodies of four strains of A. cylindracea (DC.) Marie. The amount of additive to sawdust substrate affects rate of mycelial growth and yield of investigated strains. A. cylindracea mycelial growth was not affected by addition of CaCO3 to substrate, however a significant effect of this additive was found on yield, which was the highest with CaCO3 addition in an amount of 8 g/100 g of substrate. Carpophores characterized with the largest caps diameter, and the largest individual mass obtained of substrate enriched with CaCO3 addition of 8 g/100 g of substrate. In addition, it was found that supplementation with CaCO3 affect storability of A. cylindracea. The lowest weight loss of fruiting bodies after 3 and 7 days of storage was found with addition of CaCO3 to substrate in an amount of 4 g/100 g of substrate.