Poplar Cultivars Research Articles

Genetic identification of 91 poplar cultivars based on SSR markers

Accurate genetic identification and relationship analysis of poplar cultivars is necessary to establish commercial poplar plantations and select suitable breeding strategies. In this study, 91 poplar cultivars belonging to four sections (Aigeiros, Tacamahaca, Populus and Turanga) and inter/intra‐sectional hybrids were genotyped using 18 polymorphic simple sequence repeat (SSR) markers. In total, 222 alleles were amplified with an average of 12.3 alleles per marker. The mean polymorphic information content and power of discrimination were 0.706 and 0.813, respectively. Five SSR markers (ORPM_103, ORPM_247, GCPM_1048, GCPM_1255 and LG_X_19) constituted a core fingerprint and were sufficient to identify all the tested cultivars. With some notable exceptions, cultivars of the same species generally clustered together in cluster (UPGMA) and ordination (PCO) analyses. Flow cytometry indicated that 11 poplar cultivars were triploid. Among these, seven had three alleles at some loci, suggesting that SSR markers could indicate the ploidy level to some extent. This study provides useful genetic information for the identification and protection of poplar cultivars in China and offers a guideline for the selection of poplar crossing parents based on ploidy level and genetic relationships.

Insights of Molecular Mechanism of Xylem Development in Five Black Poplar Cultivars.

Black poplar (Populus deltoides, P. nigra, and their hybrids) is the main poplar cultivars in China. It offers interesting options of large-scale biomass production for bioenergy due to its rapid growth and high yield. Poplar wood properties were associated with chemical components and physical structures during wood formation. In this study, five poplar cultivars, P. euramericana ‘Zhonglin46’ (Pe1), P. euramericana ‘Guariento’ (Pe2), P. nigra ‘N179’ (Pn1), P. deltoides ‘Danhong’ (Pd1), and P. deltoides ‘Nanyang’ (Pd2), were used to explore the molecular mechanism of xylem development. We analyzed the structural differences of developing xylem in the five cultivars and profiled the transcriptome-wide gene expression patterns through RNA sequencing. The cross sections of the developing xylem showed that the cell wall thickness of developed fiber in Pd1 was thickest and the number of xylem vessels of Pn1 was the least. A total of 10,331 differentially expressed genes were identified among 10 pairwise comparisons of the five cultivars, most of them were related to programmed cell death and secondary cell wall thickening. K-means cluster analysis and Gene Ontology enrichment analysis showed that the genes highly expressed in Pd1 were related to nucleotide decomposition, metabolic process, transferase, and microtubule cytoskeleton; whereas the genes highly expressed in Pn1 were involved in cell wall macromolecule decomposition and polysaccharide binding processes. Based on a weighted gene co-expression network analysis, a large number of candidate regulators for xylem development were identified. And their potential regulatory roles to cell wall biosynthesis genes were validated by a transient overexpression system. This study provides a set of promising candidate regulators for genetic engineering to improve feedstock and enhance biofuel conversion in the bioenergy crop Populus.

Some properties of plywood produced from 10 cultivars of poplar

ABSTRACTThe aim of this paper is to study the possible influence of poplar cultivar and soil on the mechanical properties of plywood produced from 10 cultivars having grown in different soils. For each cultivar, two trees were harvested per station; crosscut into bolts then peeled 1.4 mm thick for one tree and 3 mm thick for the other one: in total, 80 trees were sampled. The veneers were used to make 160 boards using 2 adhesives: polyvinyl acetate (PVAc) and melamine-urea-formaldehyde (MUF). These boards were then cut into standardized samples for non-destructive and destructive mechanical tests. The properties of plywood were characterized by measuring their density, modulus of elasticity and modulus of rupture. The results showed that poplar plywood properties could be influenced by adhesive and veneer thickness. The cultivar and soil effects were never relevant. A tight correlation was found between destructive and non-destructive modulus of elasticity tests.

Identification of Genes Underlying the Resistance to Melampsora larici-populina in an R Gene Supercluster of the Populus deltoides Genome.

Identification of the particular genes in an R genes supercluster underlying resistance to the rust fungus Melampsora larici-populina in poplar genome remains challenging. Based on the de novo assembly of the Populus deltoides genome, all of the detected major genetic loci conferring resistance to M. larici-populina were confined to a 3.5-Mb region on chromosome 19. The transcriptomes of the resistant and susceptible genotypes were sequenced for a timespan from 0 to 168 hours postinoculation. By mapping the differentially expressed genes to the target genomic region, we identified two constitutive expression R genes and one inducible expression R gene that might confer resistance to M. larici-populina. Nucleotide variations were predicted based on the reconstructed haplotypes for each allele of the candidate genes. We also confirmed that salicylic acid was the phytohormone mediating signal transduction pathways, and PR-1 was identified as a key gene inhibiting rust reproduction. Finally, quantitative reverse transcription PCR assay revealed consistent expressions with the RNA-sequencing data for the detected key genes. This study presents an efficient approach for the identification of particular genes underlying phenotype of interest by the combination of genetic mapping, transcriptome profiling, and candidate gene sequences dissection. The identified key genes would be useful for host resistance diagnosis and for molecular breeding of elite poplar cultivars exhibiting resistance to M. larici-populina infection. The detected R genes are also valuable for testing whether the combination of individual R genes can induce durable quantitative resistance.

Особливості вкорінення та росту живцевих саджанців культиварів тополі у судібровних умовах Київського лісостепу

Наведено значення та актуальність плантаційного лісовирощування у контексті процесу відтворення лісів та ефективного використання земельних ресурсів, інтенсифікації лісогосподарського виробництва. Приділено увагу історичним аспектам плантаційного лісовирощування, коли мали місце неодноразові спроби створення насаджень швидкорослих видів, у тому числі тополі, як у малолісних, так і промислово розвинених регіонах. Основна мета проведених досліджень полягала у здійсненні попередньої фахової оцінки придатності апробованих в експерименті культиварів тополі для плантаційного вирощування у судібровних умовах північної частини Правобережного Лісостепу за особливостями укорінення живців і ростом живцевих саджанців їхніх клонів у тестових плантаціях, починаючи з фази приживлення. Зазначено, що дослідження програмних питань проведено з використанням загальноприйнятих у лісівництві методик і загальнонаукових методів: аналізу, синтезу, порівняння і узагальнення отриманих наукових матеріалів. Придатність окремих культиварів тополі для вирощування у судібровних лісорослинних умовах оцінювали з використанням фітоіндикаційного методу. Охарактеризовано особливості вкорінення здерев’янілих живців та росту однорічних живцевих саджанців різних клонів тополі на тестовій лісосировинній плантації в умовах вологої судіброви Київського лісостепу. Здійснено попередню фахову оцінку науково обґрунтованої придатності використання в умовах вологої судіброви окремих культиварів тополі вітчизняної та зарубіжної селекції. Встановлено, що з апробованих в експерименті культиварів тополі в умовах регіону досліджень у фазі приживлення краще вкорінюються живці та інтенсивніше ростуть живцеві саджанці клонів ‘Ijzer-5’ і ‘Ghoy’. Гірше вкорінюються здерев’янілі живці тополь ‘I-214’ і ‘I- 45/51’, а повільніше ростуть – однорічні саджанці тополі Торопогрицького, ‘San Giorgio’ і ‘Blanc dе Poitou’. Логічним поясненням виявлених особливостей є специфічне відношення зазначених культиварів до родючості ґрунтів та їх вологоємності, які необхідно.

Зміни анатомо-морфологічних показників рослин роду Аcer L. в умовах м. Дніпро

Вивчено видоспецифічні особливості анатомо-морфологічних показників одно-річних пагонів представників роду Acer L. Показано різницю параметрів гістологіч-них елементів пагонів дерев, що зростають на узбіччі автострад, та дерев з умовночистої зони. Виявлено пряму залежність між розмірами короку, первинної і вторин-ної кори та здатністю дерев протидіяти антропогенному впливу. Встановлено, що заанатомічною будовою найбільш толерантним до впливу техногенних емісій виявив-ся A. pseudoplatanus L., найбільш чутливим – A. negundo L.

Trace Metal(oid) Accumulation in Edible Crops and Poplar Cuttings Grown on Dredged Sediment Enriched Soil.

The development of a biomonitor in the context of multiple-element contamination in urban environments was tested by comparing element transfer in edible crops and poplar ( Torr. × A. Henry cutlivar 'Skado'). A multielemental analysis was performed with various common edible crops (cucumber [ L.], pepper [ L.], cabbage [ L.], and lettuce [ L.]) and the Skado poplar cultivar grown on soils that received sediments dredged from water canals in the 1960s. Sediments were distributed unevenly on the soil, allowing us to sample two types of areas that were either weakly (Area 1) or highly (Area 2) contaminated, mainly by Cd, Pb, and Zn. We registered an accumulation of Cd and Zn in the edible parts of crops, with higher values recorded for leafy vegetables than for fruit vegetables. We did not detect any accumulation of Pb in the plant species studied. We calculated the fresh mass that must be consumed daily to reach tolerable daily intake (TDI) recommendations for each element and found evidence that Cd could be ingested in sufficient amounts to reach the TDI in this context. Poplar and pepper leaves accumulated more Cd and Zn than the edible parts of the study crops grown on both substrates, which suggests that poplar and pepper may be suitable species for biomonitoring element transfer to vegetation in this context.

Breeding progress and preparedness for mass-scale deployment of perennial lignocellulosic biomass crops switchgrass, miscanthus, willow and poplar.

Genetic improvement through breeding is one of the key approaches to increasing biomass supply. This paper documents the breeding progress to date for four perennial biomass crops (PBCs) that have high output–input energy ratios: namely Panicum virgatum (switchgrass), species of the genera Miscanthus (miscanthus), Salix (willow) and Populus (poplar). For each crop, we report on the size of germplasm collections, the efforts to date to phenotype and genotype, the diversity available for breeding and on the scale of breeding work as indicated by number of attempted crosses. We also report on the development of faster and more precise breeding using molecular breeding techniques. Poplar is the model tree for genetic studies and is furthest ahead in terms of biological knowledge and genetic resources. Linkage maps, transgenesis and genome editing methods are now being used in commercially focused poplar breeding. These are in development in switchgrass, miscanthus and willow generating large genetic and phenotypic data sets requiring concomitant efforts in informatics to create summaries that can be accessed and used by practical breeders. Cultivars of switchgrass and miscanthus can be seed‐based synthetic populations, semihybrids or clones. Willow and poplar cultivars are commercially deployed as clones. At local and regional level, the most advanced cultivars in each crop are at technology readiness levels which could be scaled to planting rates of thousands of hectares per year in about 5 years with existing commercial developers. Investment in further development of better cultivars is subject to current market failure and the long breeding cycles. We conclude that sustained public investment in breeding plays a key role in delivering future mass‐scale deployment of PBCs.

Адаптивність та особливості росту сортів тополі в умовах Поділля

Досліджено особливості укорінення та росту сортів тополі. Всього вивчено 10 сортів тополі української та зарубіжної селекції, для яких характерна різна інтенсивність росту в умовах Харківщини. Використано живці таких культиварів: 'Версія', 'Волосистоплода', 'Константа', 'Львівська', 'Новоберлінська', 'Ноктюрн', 'Перспективна', 'Російська', 'Слава України', 'Стрілоподібна'. Оцінено вплив умов середовища (типів лісорослинних умов) на здатність до укорінення та ріст сортів тополі. Для оцінювання взаємодії сорт – середовище розраховано індекси: ековаленсія Вріске, показник стабільності Шукля, ранжування генотипів за стійкістю до середовища, показник стабільності Канга. Комплексна оцінка перспективності сорту включала показники укорінення, енергії росту та адаптивності до умов середовища. За результатами досліджень виявлено, що найоптимальнішими для вирощування тополі є умови сирого груду (D4). Найвищою енергією росту на найбільш зволожених ґрунтах відрізнялися сорти 'Львівська', 'Новоберлінська' та 'Версія'. В умовах мінімального зволоження за висотою переважали культивари: 'Волосистоплода', 'Львівська' і 'Константа'. За комплексною оцінкою щодо здатності до укорінення, інтенсивності росту та адаптивності до умов середовища найперспективнішими є сорти 'Львівська' та 'Новоберлінська'. Сорт 'Волосистоплода' доцільно використовувати як один із найстійкіших у посушливих умовах.

Effect of Poplar Cultivar “Hybrid 275” Fiber Impregnation with 1,3-Dimethylol-4,5-dihydroxyethyleneurea on the Properties of High Density Fiberboards

Wood from the fast-growing poplar cultivar Hybrid 275 (P. maximowiczii x trichocarpa) was defibrated under industrial conditions, and the resulting fibers were subjected to impregnation modification with 5% or 10% 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU). The modified fibers were used to produce 3-mm thick high density fiberboards (HDF). The mechanical testing revealed that DMDHEU provided an increase in modulus of elasticity (MOE) and a decrease in modulus of rupture (MOR); however, all panels met the requirements of the European Standard EN 310 (1993). Increases of 1.5-fold and 2.5-fold in internal bonding (IB) compared to the unmodified reference panels were observed. The modification resulted in reduced HDF interactions with water, manifested by decreased water absorption, thickness swelling, and reduced water wetting. The modification also provided the panels with an improved resistance to moulds.

Inter-annual variation of tree-ring width, δ13C and δ18O in juvenile trees of five plantation poplar cultivars (Populus spp.)

The 10-year juvenile records of three hybrid poplar and two aspen cultivars (Populus spp.) from a short rotation coppice (SRC) were assessed by measuring tree-ring width (annual radial increment, ir) and stable isotope ratios of carbon and oxygen (δ13C and δ18O) of α-cellulose. All cultivars showed common ‘juvenile trends’ that were modeled with nonlinear fit (NLF) functions. The ir of all cultivars culminated in the middle of the juvenile phase. Within the first ten years, δ13C showed a gradual decrease of approximately 2.5 ‰ in all cultivars and δ18O showed an asymptotic increase which was variable among the poplar cultivars and which was more pronounced in two hybrid poplars. Potential causes of the juvenile inter-annual variability of δ13C and δ18O were discussed. Likely, the maturation related changes in hydraulic architecture, the canopy closure and the resulting increase of the proportion of shaded crown segments which have lower photosynthetic capacities had an effect on δ13C. An additional effect of changes in N nutrition on δ13C is assumed at the present SRC trial because the NO3− concentration had significantly decreased after ten years. Interpretation of δ18O data remained difficult given the lack of soil water δ18O records.The maturation effect and the respective interaction have resulted in large temporal variability in the present three investigated tree ring traits. However, the impact of two drought vegetation periods (2003 and 2006) was still reflected by the juvenile tree ring records of all traits. Different juvenile trends in the records of the stable isotope ratios δ13C and δ18O, and the trend slopes, which may vary between genetically different cultivars, must be considered in tree ring investigations of SRC poplars.

Productivity and biomass characteristics of selected poplar (Populus spp.) cultivars under the climatic conditions of northern Poland

This study aimed to determine the productivity and energy values of 10 poplar cultivars for use as potential fuel sources in Poland. The study was conducted over a seven-year cycle in northern Poland. The cultivars belonged to clones traditionally used for timber production, as well as new clones specific to short-rotation coppice (SRC) practices. Biomass production and biomass properties were measured, including elemental composition, the gross and net calorific values (heating value) of wood, and envelope density. For each cultivar, the synthetic fuel value index (FVI) was calculated. Biomass dry matter (DM) production differed noticeably between cultivars, and it was the highest for traditional cultivars (‘NE-42’ and ‘Fritzi Pauley’, amounting to 8 Mg ha−1 yr−1), and the lowest for new cultivars (DM was one-third that of the cultivars with the highest production). Two traditional cultivars (‘NE-42’ and ‘Fritzi Pauley’) had the highest FVI, representing potential biofuels, whereas two new SRC cultivars (‘AF-8’ and ‘AF-2’) had the lowest indexes. Overall, poplar plantations with short rotations could be considered as a potential additional source of renewable energy in Poland. However, the key factor is selection of appropriate genotypes for the specific climatic conditions. In conclusion, our study demonstrated the importance of testing cultivars under local climatic conditions before using them at a commercial scale.

Yield of Pulp, Dimensional Properties of Fibers, and Properties of Paper Produced from Fast Growing Trees and Grasses

Paper is produced mainly from wood fibrous pulps, which has been increasingly replaced by pulps from fast growing plants due to limited wood resources. In this work, properties of cellulosic pulps produced by the sulfate method from four fast growing grasses, poplar cultivar 'Hybrid 275', and European larch, as well as pine and birch wood chips, were compared. In addition, the cellulosic pulp yield, dimensions of fibers contained in the pulps and mechanical and optical characteristics of paper sheets produced from the pulps were compared. The pulp yield of the poplar cultivar 'Hybrid 275' (51.6%) was almost 5% higher than birch pulp (47.0%). Moreover, all of the investigated tensile properties of paper made from ‘Hybrid 275’ pulp were higher than for paper produced from birch pulp. Fast growing grasses, despite lower pulp yield (34.0 to 47.1%), showed comparable tensile properties to birch. Therefore, these pulps are promising raw materials for papermaking.

不同浓度酚酸对欧美杨I-107苗木生长和光合特性的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 不同浓度酚酸对欧美杨I-107苗木生长和光合特性的影响 DOI: 10.5846/stxb201704120646 作者: 作者单位: 山东农业大学;临沂大学,山东农业大学,江苏省邮电规划设计院有限责任公司,临沂大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点基础研究发展计划项目（2012CB416904）；国家自然科学基金（31500511）；山东省自然科学基金联合专项（ZR2015CL044） Effects of phenolic acids on the growth and photosynthesis of Populus×euramericana ‘Neva’ Author: Affiliation: Shandong Agricultural University;Linyi University,Shandong Agricultural University,Jiangsu post & Telecommunications Planning and Designing Institute,Linyi University Fund Project: the National Basic Research Program of China ; Natural Science Foundation of China; Natural Science Foundation Joint Special Project of Shandong Province 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:模拟杨树人工林根际土壤酚酸累积，以杨树人工林二代连作土壤中酚酸含量为参考值（X），对欧美杨I-107（Populus×euramericana ‘Neva’）一年生盆栽苗木进行不同浓度酚酸（0X、0.5X、1.0X）处理，通过比较不同浓度酚酸对杨树苗木生长和生理生化特性的影响，来揭示酚酸胁迫对杨树生长的抑制作用和机理。结果表明：随酚酸浓度增加，杨树苗木净光合速率（Pn）、气孔限制值（Ls）、蒸腾速率（Tr）、水分利用效率（WUE）、最大净光合速率（Pnmax）、表观光合量子效率（φ）、暗呼吸速率（Rd）、最大荧光（Fm）、光系统Ⅱ（PSⅡ）实际光化学效率（φPSⅡ）、PSⅡ最大光化学效率（Fv/Fm）、叶绿素（Chl）荧光光化学淬灭（qP）、表观光合电子传递速率（ETR）、Chl含量和苗木总生物量显著降低，杨树苗木胞间CO2浓度（Ci）、光补偿点（LCP）、叶绿素初始荧光（Fo）、非光化学淬灭（NPQ）、丙二醛（MDA）含量和苗木根茎比明显增大。结论：酚酸显著抑制杨树苗木的光合作用、蒸腾作用和呼吸作用，且酚酸浓度越大，抑制作用越强；随着酚酸浓度的增加，杨树苗木有机物积累明显降低，叶片细胞受到显著伤害。光合机构通过增加热耗散实施光保护，光合产物更多的向苗木地下部分分配，是杨树适应酚酸胁迫的生理对策。 Abstract:The degradation of forestland productivity in continuous-cropping poplar plantations is strongly related to the accumulation of phenolic acids in the soil. Therefore, the present study aimed to examine the effects of phenolic acid concentration on the photosynthetic characteristics and growth traits of poplar and to clarify the stress mechanism of phenolic acids on poplar growth. We established three treatments (CK, 0.5X, and 1.0X), based on the field concentration (X) of phenolic acids in the soil of a second-generation continuous-cropping poplar plantation and measured the physiological and biochemical parameters and growth indices of treated one-year-old black poplar cultivar I-107 (Populus×euramericana ‘Neva’). The results indicated that net photosynthetic rate (Pn), stomatal limitation (Ls), water use efficiency (WUE), transpiration rate (Tr), light-saturated net photosynthetic rate (Pnmax), apparent quantum yield (φ), dark respiration rate (Rd), maximal fluorescence yield of the dark-adapted state (Fm), effective quantum efficiency of PSⅡ (φPSⅡ), potential quantum efficiency of PSⅡ (Fv/Fm), photochemical quenching coefficient (qP), electron transport rate (ETR), chlorophyll (Chl) content, and total biomass decreased significantly with increasing concentrations of phenolic acids, whereas the intercellular CO2 concentration (Ci), light compensation point (LCP), minimal fluorescence yield of the dark-adapted state (Fo), non-photochemical quenching (NPQ), malondialdehyde (MDA) content, and root/shoot ratio (R/S) increased significantly. We concluded that phenolic acid stress significantly reduces the photosynthesis, transpiration and respiration of poplar and that phenolic acid concentration and the inhibition of the poplar's physiological activities are positively correlated. With increasing phenolic acid concentrations, the organic matter accumulation of the poplar seedlings decreased significantly, and poplar leaf cells were seriously damaged. Therefore, poplar responds to phenolic acid stress by increasing the dissipation of excess light energy to alleviate damage to the photosynthetic apparatus under strong light conditions and by distributing photosynthates underground to promote root growth and nutrient absorption. 参考文献 相似文献 引证文献

The escalatory Red Queen: Population extinction and replacement following arms race dynamics in poplar rust

Host-parasite systems provide convincing examples of Red Queen co-evolutionary dynamics. Yet, a key process underscored in Van Valen's theory - that arms race dynamics can result in extinction - has never been documented. One reason for this may be that most sampling designs lack the breadth needed to illuminate the rapid pace of adaptation by pathogen populations. In this study, we used a 25-year temporal sampling to decipher the demographic history of a plant pathogen: the poplar rust fungus, Melampsora larici-populina. A major adaptive event occurred in 1994 with the breakdown of R7 resistance carried by several poplar cultivars widely planted in Western Europe since 1982. The corresponding virulence rapidly spread in M. larici-populina populations and nearly reached fixation in northern France, even on susceptible hosts. Using both temporal records of virulence profiles and temporal population genetic data, our analyses revealed that (i) R7 resistance breakdown resulted in the emergence of a unique and homogeneous genetic group, the so-called cultivated population, which predominated in northern France for about 20years, (ii) selection for Vir7 individuals brought with it multiple other virulence types via hitchhiking, resulting in an overall increase in the population-wide number of virulence types and (iii) - above all - the emergence of the cultivated population superseded the initial population which predominated at the same place before R7 resistance breakdown. Our temporal analysis illustrates how antagonistic co-evolution can lead to population extinction and replacement, hence providing direct evidence for the escalation process which is at the core of Red Queen dynamics.

Metabolomics reveals constitutive metabolites that contribute resistance to fall webworm (Hyphantria cunea) in Populus deltoides

Constitutive chemical defenses play important roles in protecting trees against insects. Studying the constitutive chemical resistance of trees to insect would thus help control the pests and minimize the associated ecological and economic losses. Poplar is an ecologically and economically important tree species but has been greatly damaged by fall webworm (Hyphantria cunea) in China. Here we investigated H. cunea resistance in 7 poplar cultivars commonly planted in China by applying bioassays, and analyzed metabolic profiles of H. cunea -resistant and -susceptible cultivars. Substantial variation in chemical profiles between resistant and susceptible genotypes was detected. Ninety-two distinguishing metabolites were identified. Correlation analysis indicated that hydroxycinnamates, benzenoids and their derivatives significantly positively correlated with resistance against H. cunea, whereas sucrose, glutamic acid and myo-inositol showed negative correlations. Bioassays of H. cunea given an artificial diet supplemented with these compounds confirmed their effects but indicated that they each have different roles. Metabolite enrichment and gene expression analysis showed that phenylpropanoid biosynthesis in poplar is important for constitutive resistance against H. cunea. Induced experiment found that some of the constitutive resistance-related metabolites were induced by H. cunea indicating that these metabolites also play a role in induced resistance. This study provides further insight into the molecular mechanisms behind H. cunea resistance in poplar and suggests candidate metabolites that may serve as biomarkers for breeding of resistant poplar cultivars.

Biomass productivity of selected poplar (Populus spp.) cultivars in short rotations in northern Poland§

Renewable energy sources such as biomass are an important aspect of the energy policy of the European Union. As the use of ‘full-value wood’ for energy purposes has been restricted, short-rotation forestry may be an alternative source of woody biomass. In Poland, the most promising genus is poplar (Populus spp.). Ten poplar cultivars from the Aigeiros or Tacamahaca sections of the genus Populus were compared in 5- and 6-year rotations for biomass components and yields. Additional aims were to preliminarily (a) identify a suitable rotation length and (b) evaluate the sprouting capacity of various cultivars in the climate of northern Poland. The following variables were measured: diameter at breast height (DBH), height, survival rate, single-tree dry mass, crop biomass production, and sprouting ability. The cultivars ‘NE-42’ and ‘Fritzi Pauley’ showed the best growth characteristics (DBH and height) and highest biomass production (7.6 and 7.7 t ha−1 year−1, and 5.2 and 6.9 t ha−1 year−1, respectively, for cultivars in the 5- and 6-year cycles). These cultivars were also distinguished by a large number of coppice shoots and a high shoot length. Eight cultivars did well enough to produce worthwhile data, and five of these gave higher biomass production (t DM ha−1 year−1) during the 6-year, as opposed to the 5-year cycle. Of the eight cultivars analysed, ‘AF-8’ had the poorest growth parameters and produced two thirds less dry biomass than either the ‘NE-42’ or ‘Fritzi Pauley’ cultivars. Data for two Italian cultivars (‘AF-6’ and ‘MON’) were not analysed because of their cold tenderness and their high mortality. Rotation length is important for biomass production in energy plantations. Most of the tested poplar cultivars gave higher biomass productivity over an initial 6-year cycle than over a 5-year one. Our preliminary results suggest that the ‘NE-42’ and ‘Fritzi Pauley’ cultivars performed best among those tested. Both of these have been tested previously in Poland in medium and long rotations. The data indicate the importance of testing cultivars under local climatic conditions before planting on a commercial scale.

Combined surface drip irrigation and fertigation significantly increase biomass and carbon storage in a Populus × euramericana cv. Guariento plantation

Fast-growing poplar plantations are considered of great benefit to both timber production and carbon (C) sequestration, and are increasingly planted for multiple purposes worldwide. Irrigation and fertilization are common management practices in plantations in semiarid regions. However, quantitative investigation of the integrative effect of surface drip irrigation and fertigation (SDIF) on biomass and C storage in poplar plantations remains limited. In this study, we conducted a field experiment on a fast-growing poplar cultivar (Populus × euramericana cv. Guariento) plantation to compare the combination of surface drip irrigation and fertigation in growing seasons with conventional management (control; CK). Experiments repeated over 2 years showed that SDIF significantly increased biomass and C storage in both trees and soil in the plantation compared with the CK. Tree biomass C in SDIF-treated and CK stands after the first year of the experiment (age 5) was 6.20 and 4.05 t C ha−1, respectively, and the difference further increased, i.e., 15.18 and 8.63 t C ha−1, respectively, after the second year of the experiment (age 6). There was 53 and 76 % higher C storage in SDIF-treated trees than in the CK trees after the first and second years of the experiment, respectively. The SDIF increased the soil C concentration, especially in the surface soil at 0- to 40-cm depth. Soil organic C at a depth of 0–60 cm under the SDIF treatment was 45.42, 50.87 and 61.32 t C ha−1 in the 1st, 2nd and 3rd years, respectively, with annual increases of 12 and 21 % between the first and second, and second and third year, respectively. The corresponding soil organic C in the CK was 43.08, 43.57 and 47.92 t C ha−1 in the 1st, 2nd and 3rd years; the annual increases were only 1 and 10 %, respectively. The results confirmed the significant effect of the combined management on C storage in poplar plantations, thus we suggest it can be applied in forestry management, even though it generally did not change C concentrations of tree components.

Impact of poplar-based phytomanagement on soil properties and microbial communities in a metal-contaminated site.

Despite a long history of use in phytomanagement strategies, the impacts of poplar trees on the structure and function of microbial communities that live in the soil remain largely unknown. The current study combined fungal and bacterial community analyses from different management regimes using Illumina-based sequencing with soil analysis. The poplar phytomanagement regimes led to a significant increase in soil fertility and a decreased bioavailability of Zn and Cd, in concert with changes in the microbial communities. The most notable changes in the relative abundance of taxa and operational taxonomic units unsurprisingly indicated that root and soil constitute distinct ecological microbial habitats, as exemplified by the dominance of Laccaria in root samples. The poplar cultivar was also an important driver, explaining 12% and 6% of the variance in the fungal and bacterial data sets, respectively. The overall dominance of saprophytic fungi, e.g. Penicillium canescens, might be related to the decomposition activities needed at the experimental site. Our data further highlighted that the mycorrhizal colonization of poplar cultivars varies greatly between the species and genotypes, which is exemplified by the dominance of Scleroderma under Vesten samples. Further interactions between fungal and bacterial functional groups stressed the potential of high-throughput sequencing technologies in uncovering the microbial ecology of disturbed environments.

Early root and aboveground biomass development of hybrid poplars (Populusspp.) under drought conditions

Currently, the genus Populus is one of the favourite objects for research of molecular genetics of woody plants. A high growth rate and the broadly applicable timber as raw material for different types of products made of wood make poplar attractive for industrial usage. Despite the positive aspect of its growth capacity and wood composition, one major problem in cultivating fast-growing tree species in a forestry plantation system is the comparably high water demand of the plants. In this context, a rapid development of an efficient adventitious root system from dormant hardwood cuttings is an essential requirement for the successful establishment of short-rotation cultures. It reduces the establishment costs of plantations, and the developing plant can be transferred into favourable conditions due to varying environmental conditions. Results of greenhouse pot and soil-column experiments on the development of shoots and adventitious roots from hardwood cuttings of seven hybrid poplar cultivars and the reaction of the plants performance on varying water availability will be presented. We estimated root and shoot length, root and shoot growth and biomass accumulation over time, root-to-shoot length ratio, and root morphological traits.