Stefan Szczukowski

Biological diversity of Salix taxa in Cu, Pb and Zn phytoextraction from soil

ABSTRACT The aim of the study was to estimate the efficiency of copper (Cu), lead (Pb) and zinc (Zn) phytoextraction by 145 Salix taxa cultivated in an area affected by industrial activity. Survivability and biomass of plants were also analyzed. The highest Cu, Pb and Zn content in shoots was 33.38 ± 2.91 (S. purpurea × viminalis 8), 24.64 ± 1.97 (S. fragilis 1) and 58.99 ± 4.30 (S. eriocephala 7) mg kg−1 dry weight, respectively. In the case of unwashed leaves, the highest content of these metals was 135.06 ± 8.14 (S. purpurea 26), 67.98 ± 5.27 (S. purpurea 45) and 142.56 ± 12.69 (S. alba × triandra 2) mg kg−1 dw, while in washed leaves it was 106.02 ± 11.12 (S. purpurea 45), 55.06 ± 5.75 (S. purpurea 45) and 122.87 ± 12.33 (S. alba × triandra 2) mg kg−1 dw, respectively. The differences between the highest and lowest values for Cu, Pb and Zn were 545%, 20500% and 535% in shoots; 2692%, 2560% and 7500% in unwashed leaves; and 3286%, 2221% and 6950% in washed leaves, respectively. S. acutifolia was able to effectively accumulate all three metals jointly, producing shoots that were well developed in both length and diameter when compared with the other tested willows—an ability that would suggest its high suitability for practical application.

Characteristics of Thermophysical Parameters of Selected Salix Taxa with Elemental Analysis

In an experiment conducted in the spring of 2011, 3600 cuttings of 145 Salix taxa were cultivated, which were subsequently harvested after 1 year and analyzed for thermophysical and chemical properties. Statistical analysis followed by grouping of the objects enabled us to find significant differences between the Salix genotypes. Two different groups (of 35 and 110 varieties each) were found with average values of higher heating value of 19.75 and 19.27 MJ kg−1 d.w., respectively, while in terms of lower heating value three groups were identified (consisting of 39, 102, and 4 taxa), represented by average values of 18.27, 17.06, and 16.52 MJ kg−1 d.w., respectively. In our opinion, moisture content of fresh material (three groups with average moisture contents of 9.14%, 7.29%, and 4.47% d.w., respectively) is the main indicator distinguishing the above findings. The tested varieties were also divided into three groups according to their volatile matter contents (14, 121, and 10 genotypes with average values of 76.47%, 74.80%, and 72.97% d.w., respectively) as well as fixed carbon content (with 21.3%, 20.23%, and 19.08% d.w., respectively, for groups of 23, 110, and 12 taxa). Also three groups of varieties (11, 121, and 13 taxa) were distinguished in terms of the level of ash (4.16%, 2.77%, and 1.84% d.w., respectively). Differences in the elemental levels of C, H, and S in tested Salix taxa were found as well.