Populus nigra

More recently plant analysis has been carried out to screen for the accumulation of metals indicative of pollution. Usually metal concentrations are reported in dry plant material. However, it has been suggested (Claussen, 1990) that the concentrations of pollutants are better related to the dry ash of a plant, than to the dry weight, since it eliminates the natural variations of organic matter. Heavy metal concentrations in ash of Populus nigra Italica were reported to correlate better with values in air and soil than those in dry plant material. 

Fig. 8-5. Comparison of results for concentrations of Zn, Pb and Cd in standardised leaves of the Lombardy poplar (Populus nigra Italica ) from different locations and years (from Wagner, 1993, reprinted with permission).

Hydroxyflavanone represents the simplest compound of this class and is found in many legumes.9 2-Hydroxyflavanones, which are expected to be quite labile and converted to their corresponding flavones, have also been identified. These include the 2,5,7-trihydroxyflavanone 7-0-glucoside (8) in Malus spp.,80 2,5-dihydroxy-7-methoxyflavanone in Populus nigra, 1 6,7,8-trihydroxy-5-methoxyflavanone (9) in Isodon oresbius,82 and 2,5-dihydroxy-7-methoxyflavanone and its 6-C- and 8-C-methyl isomers (10) in Friesodielsia enghiana.83 All of these exhibit a lack of B-ring hydroxylation. 

CHADENSON, M HAUTEVILLE, M CHOPIN, J., Synthesis of 2,5-dihydroxy-7-methoxyflavone, cyclic structure of the benzoyl (2,6-dihydroxy-4-methoxybenzoyl)-methane from Populus nigra buds. J. Chem. Soc., Chem. Common., 1972, 107-108. 

Fig. 3. Geometries of the type 1 copper sites of various blue copper proteins. The trigonal planar geometry is the type 1 site of laccase from Coprinus cinereus (PDB Code 1A65). The trigonal bipyramidal geometry shown is the copper site of azurin from Pseudomonas aeruginosa (PDB Code lAZU). The trigonal pyramidal/distorted tetrahedral sites are of the stellacyanin from Cucumis sativus (PDB Code IJER), NNSO site, and of the plastocyanin from Populus nigra (PDB Code IPLC) NNSS site.

Several species of Salix and Populus America [ Populus nigra Populus baisamifera... 

Red beech (Fagus sylvatica) / Lombardy Poplar (Populus nigra Ttalica ) Leaves... 

Djingova, R., Wagner, G Peshev, D., 1995b. Heavy metal distribution in Bulgaria using Populus nigra Ttalica as a biomonitor. Sci. Total Environ. 172, 151-158. 

Djingova, R, Wagner, G Kuleff, 1., Peshev, D 1996. Investigation of the time-dependant variations in metal concentration in the leaves of Populus nigra Italica . Sci. Total Environ. 184, 197-203. 

Fig. 15. Resonance Raman spectra of three blue copper proteins A. denitrificans azurin at 90 K (568.2 nm excitation), P. aeruginosa azurin at 12 K (647.1 nm excitation), and Populus nigra plastocyanin at 12 K (604 nm excitation). ...

Chrysin (5,7-dihydroxyflavone). Formula, see fla-vones, C15H10O4, Mr 254.24, pale yellow crystals, mp. 285-286 °C, insoluble in water, soluble in alkalis and ethanol used as complexation reagent for Cu. C. occurs together with its 7-methyl ether in poplar buds (Populus nigra, Salicaceae), in the heartwood of various Pinus species (Pinaceae) and the sweet cherry (Prunus avium, Rosaceae). 

Y. Gharridre-Ladreix, Distribution intracellu-laire et caracteristiques de la phenylalanine ammoniac-lyase chez Populus nigra L., Physiol, vdgdtale 3 (1978). 

Kaffeesaure-3-O-p-D-glucosid, Schmp. 206—208°, o(d= —66° (Methanol) Acetat Schmp. 199—200°, ao = —46° (Athanol). Vorkommen Blatter von Populus nigra (276) und Beeren knollenbildender Wildkartoflfeln (Solanum-SpQciQs) (109). 

The young buds of the black poplar, Populus nigra, yield from 03 to 0 6 per cent, of an essential oil of a pale yellow colour, with an odour somewhat recalling that of chamomiles. It has the following characters —... 

---