Salix Taxa Research Articles

Unusual hydrocarbon waxes detected in Salix oritrepha leaf from Nianbaoyeze Mountains, eastern Qinghai-Tibetan Plateau

Plant biomarkers, such as hydrocarbon waxes, are frequently found in various sediments and could be adopted as paleovegetation and paleoclimate indicators. Nevertheless, scarce researches have focused on leaf waxes in higher plants of alpine region. Herein, hydrocarbon leaf wax components of Salix oritrepha, which flourish in Nianbaoyeze Mountains in eastern Tibetan Plateau were fully discussed. The n-alkane distribution in leaves ranges from n-C21 to n-C29 with maxima at n-C25, which were entirely different with Salix taxa displayed in previous surveys in non-alpine regions. The unusual even carbon nalkenes from n-C22:1 to n-C30:1, which were thought to appear only in aquatic organisms, were firstly reported in an alpine plant. Additionally, iso-(2-methyl) alkanes, ranging from i-C23 to i-C29 with maxima at i-C25, which have been commonly reported in microorganisms, were also identified in an alpine plant for the first time. Unusual hydrocarbon distribution detected in Salix oritrepha leaf from Nianbaoyeze Mountains is most likely due to the extreme environment in such alpine region.

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

ABSTRACTThe 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.

Molecular evidence indicates that subarctic willow communities in Scotland support a diversity of host-associated Melampsora rust taxa

Rare and threatened subarctic willow scrub communities in the UK are the subject of ongoing conservation programmes, yet little is known about the diversity of fungal taxa that they support. Isolates of the rust genus Melampsora were sampled from 112 leaves of eight subarctic willow (Salix) taxa and their hybrids from twelve sites in the UK. In order to determine the number of Melampsora taxa present in the samples, isolates were sequenced for the Internal Transcribed Spacer (ITS) region of rDNA and data were subject to phylogenetic analysis. Maximum likelihood and Bayesian analysis indicated that the isolates fell into three strongly supported host-associated clades. Clade I contained only isolates from Salix herbacea and was distinguished morphologically by dense urediniospore echinulation and thin cell walls. Clade II contained isolates from Salix arbuscula and Salix reticulata only. These could not be distinguished morphologically from isolates in Clade III which were found on Salix lapponum, Salix myrsinites, Salix myrsinifolia, Salix aurita, Salix lanata, and their hybrids. Clade II was most distinct in ITS sequence, differing by 50 bases from Clades I and III, while the latter clades differed in sequence by only 24 bases on average. Clades I and III are likely to represent the previously recognised taxa Melampsora alpina Juel 1894 and Melampsora epitea Thüm. 1879 respectively, but Clade II has not apparently been described before. Significant differences in the intensity of infection by isolates of Clade III were found among different Salix species at a single site, suggesting either differences in resistance among Salix taxa, or the presence of further cryptic taxa within Clade III. The study illustrates the power of molecular phylogenetic analysis to reveal cryptic biodiversity within Melampsora, and suggests that conserving Salix host diversity within subarctic willow communities will ensure that a diversity of associated Melampsora taxa is maintained.

DNA barcoding: a tool for improved taxon identification and detection of species diversity

Recently it was decided that portions of rbcL and matK gene regions are approved and required standard barcode regions for land plants. Ideally, DNA barcoding can provide a fast and reliable way to identify species. Compiling a library of barcodes can be enhanced by the numerous specimens available in botanic gardens, museums and herbaria and in other ex situ conservation collections. Barcoding can strengthen ongoing efforts of botanic gardens and ex situ conservation collections to preserve Earth’s biodiversity. Our study aimed to detect the usability of the universal primers of the standard DNA barcode, to produce standard barcodes for species identification and to detect the discriminatory power of the standard barcode in a set of different groups of plant and fungal taxa. We studied Betula species originating from different parts of the world, and Salix taxa, bryophytes and edible and poisonous fungal species originating from Finland. In Betula and Salix, the standard DNA barcode regions, portions of matK and rbcL, were able to identify species to genus level, but did not show adequate resolution for species discrimination. Thus, supplementary barcode regions are needed for species identification. In Salix, the trnH-psbA spacer was also used, and it proved to have more resolution but, yet, not adequate levels of interspecific divergence for all studied taxa. In a set of bryophyte species, the rbcL gene region was found to possess adequate resolution for species discrimination for most genera studied. In bryophytes, matK failed to amplify properly. In fungi, the combination of ITS1 and ITS2 proved to be effective for species discrimination, although alignment difficulties were encountered. In general, closely related or recently diverged species are the greatest challenge, and the problem is most difficult in plants, both in terms of a suitable combination of barcoding regions and the universality of used primers.

Nuclear cyp73 intron fragment length polymorphism supports morphological analysis of Salix species and hybrids

The polyploid Salix alba L.–Salix fragilis L. hybrid complex still presents major difficulties in morphological identification. Most of the measured characters show a low diagnostic value for unambiguously identifying the parental species and their hybrid Salix × rubens Schrank due to continuous variation creating a large overlap in leaf and catkin morphology. Fragment length polymorphism of nuclear cyp73 intron markers was used to identify species and hybrids. This multilocus genotyping could be applied in a morphological analysis of trees from hybrid zones and allowed to demonstrate that morphological features of leaves and catkins clearly separated S. alba from S. fragilis. The hybrid individuals largely overlapped with both parental species but appeared to be morphologically more similar to S. fragilis than to S. alba. Cyp73 analysis of 11 Salix taxa revealed intermediate positions of two hybrid taxa with S. alba, namely S. × rubens and S. × sepulcralis Simonkai with their respective parental species S. fragilis and S. babylonica L. Additionally, the cyp73 intron multilocus genotypes clustered tetraploid taxa separately from diploid willows. Cyp73 introns are valuable markers for fast, reliable and straightforward genotyping in willow species and hybrids.

A comparative epidermis study of the Athabasca sand dune willows (Salix; Salicaceae) and their putative progenitors

The Athabasca sand dunes are located on the south shore of Lake Athabasca in northern Alberta and Saskatchewan, Canada. Four willow shrubs (Salix; Salicaceae) occur on the open sands, two of which are endemic to the Athabasca sand dunes. Light and scanning electron microscopy were used to quantify stomatal frequency, stomatal index, trichome density, and cuticle thickness, for the Athabasca sand dune willows and their associated putative progenitors. The Athabasca sand dune taxa (Salix brachycarpa var. psammophila, Salix planifolia subsp. tyrrellii, Salix silicicola, and Salix turnorii) occur primarily on the inner dunes, and each has certain leaf epidermal features that appear to be adaptive to the exposed nature of the open sand habitat and the high light intensity. Salix brachycarpa var. psammophila and S. silicicola have tomentose leaves, with trichome densities that are significantly greater than those of their respective widespread progenitors. Salix planifolia subsp. tyrrellii and S. turnorii have amphistomatic leaves and substantially thicker cuticles than their associated progenitors. This investigation is the first to compare adaptive leaf epidermis features within the derivative–progenitor Salix pairs. Considerations for the significance of amphistomaty in the Athabasca sand dune Salix taxa are discussed.Key words: Athabasca sand dunes, cuticle, Salix, stomata, trichomes, willow.

AFLP analysis sheds light on distribution of two Salix species and their hybrid along a natural gradient

Amplified fragment length polymorphism (AFLP) analysis of 26 trees of three Salix taxa: Salix alba L. (White Willow), S. fragilis L. (Crack Willow) and their hybrid S. x rubens Schrank, across an example of their habitat range in south‐west Germany, supported the distribution previously determined using morphological characterization. UPGMA and principal coordinates analysis of the AFLP data revealed three distinct clusters corresponding to the three taxa. In addition, AFLP analysis on individuals which were difficult to identify morphologically revealed that they were either the hybrid S. x rubens or S. fragilis. Four specimens of S. fragilis were indistinguishable with three primer combinations suggesting they are members of one clone.