Deltoides Clones Research Articles

Dar dikim aralıklarında kurulan kavak (Populus x euramericana ve Populus deltoides klonları) ağaçlandırmalarında artım ve büyüme

Bu çalışmada, levha ve kağıt endüstrisinin talebine uygun odun üretimine yönelik, dar dikim aralıklarındaki kavak ağaçlandırmalarının gelişimleri araştırılmıştır. Bu amaçla, P.x euramericana ve P. deltoides klonlarıyla (I-214, I-45/51, SAMSUN (I-77/51), İZMİT (S.307-26) ve 89.M.060) deneme ağaçlandırmaları tesis edilmiştir. Denemelerde 3m x 1,5m (4,5 m2/ağaç), 3m x 2m (6,0 m2), 3m x 3m (9,0 m2), 3m x 4m (12,0 m2) ve 3m x 5m (15,0 m2) olmak üzere, 5 değişik dikim aralığı uygulanmıştır. Tüm kavak klonları için, bonitet tabloları ve çift girişli hacim tabloları düzenlenmiştir. Ayrıca, 3 bonitet sınıfı ve 5 değişik dikim aralığına göre, 3 – 12 yaş kademesi için hasılat tabloları hazırlanmıştır. Dar dikim aralıklarındaki kavak ağaçlandırmalarında çap, boy ve meşcere unsurlarının artım ve büyüme ilişkileri ortaya konulmuştur. Analiz sonuçlarına göre, en uygun klonun 89.M.060 ve dikim aralığının 4,5 m2/ağaç olduğu belirlenmiştir.

First record of Cladosporium oxysporum as a potential novel fungal hyperparasite of Melampsora medusae f. sp. deltoidae and screening of Populus deltoides clones against leaf rust.

The online version contains supplementary material available at 10.1007/s13205-023-03623-x.

EYGFPuv-Assisted Transgenic Selection in Populus deltoides WV94 and Multiplex Genome Editing in Protoplasts of P. trichocarpa × P. deltoides Clone '52-225'.

Although CRISPR/Cas-based genome editing has been widely used for plant genetic engineering, its application in the genetic improvement of trees has been limited, partly because of challenges in Agrobacterium-mediated transformation. As an important model for poplar genomics and biotechnology research, eastern cottonwood (Populus deltoides) clone WV94 can be transformed by A. tumefaciens, but several challenges remain unresolved, including the relatively low transformation efficiency and the relatively high rate of false positives from antibiotic-based selection of transgenic events. Moreover, the efficacy of CRISPR-Cas system has not been explored in P. deltoides yet. Here, we first optimized the protocol for Agrobacterium-mediated stable transformation in P. deltoides WV94 and applied a UV-visible reporter called eYGFPuv in transformation. Our results showed that the transgenic events in the early stage of transformation could be easily recognized and counted in a non-invasive manner to narrow down the number of regenerated shoots for further molecular characterization (at the DNA or mRNA level) using PCR. We found that approximately 8.7% of explants regenerated transgenic shoots with green fluorescence within two months. Next, we examined the efficacy of multiplex CRISPR-based genome editing in the protoplasts derived from P. deltoides WV94 and hybrid poplar clone '52-225' (P. trichocarpa × P. deltoides clone '52-225'). The two constructs expressing the Trex2-Cas9 system resulted in mutation efficiency ranging from 31% to 57% in hybrid poplar clone 52-225, but no editing events were observed in P. deltoides WV94 transient assay. The eYGFPuv-assisted plant transformation and genome editing approach demonstrated in this study has great potential for accelerating the genome editing-based breeding process in poplar and other non-model plants species and point to the need for additional CRISPR work in P. deltoides.

Field evaluation of Populus deltoides clones for growth traits and tolerance to leaf spots

The study was conducted to evaluate the growth characters of the 16 clones of Populus deltoides under field conditions at the Main Experimental Area, Department of Forestry and Natural Resources, Punjab Agricultural University, Ludhiana following Randomised Complete Block Design with four replication and plot size of four trees. Significant variation was noticed among the clones for tree height, diameter and wood volume. Clones L-48/89, 9607, L-47/88, 9607 and 6503 Â were observed to be most promising for wood productivity. The poplar clones were found susceptible to leaf spots caused by Cercospora populina , Alternaria alternate , Drechslera sp. and Rhizoctonia sp. Clone L-48/89 with least leaf spots severity of 6.9 per cent was categorized as moderately resistant along with clone L-47/88, 9607 and T-50. Moderate susceptibility response against leaf spots was observed in clone T-59, G-48 and 5503. None of the clones exhibited resistant reaction to leaf spots.

Detection and confirmation of diagnostic microsatellite loci in Populus nigra and Populus deltoides to identify their hybrids (P. × canadensis)

Poplar cultivation has economic, social, ecological, and environmental importance in Turkey. Even though, Populus × canadensis hybrids play an important role for the commercial poplar cultivation with good growth performance and adaptability, hybrid clones introduced the different region of Turkey have started to replace the native stands of Populus nigra gradually. To continue sustainable cultivation of poplar and to conserve the native stands of P. nigra at the same time, genetic identification, and registration of the Populus cultivars from different origins are essential in breeding programs. Genetic identification and characterization of a natural population of P. nigra growing along the Melendiz River, Populus deltoides, and hybrid P. × canadensis trees were performed by 12 microsatellites loci. In addition, 18 P. nigra trees from EUFORGEN core collection were screened as reference samples. P. deltoides specific alleles were detected at four microsatellite loci previously reported as having diagnostic alleles. Several P. nigra trees from natural population and EUFORGEN core collection also included species-specific alleles of P. deltoides. It is concluded that there is an introgression event between the natural population and cultivated hybrids or P. deltoides clones in the surrounding area. Also, some members of the EUFORGEN core collection could have been mixed up or misidentified as P. nigra. The obtained results indicated that the application of the rigorous standards for reliable identification and registration with large sample size is a necessity for future breeding and conservation programs. Also, conservation of the native Populus nigra trees is an important requirement to prevent the genetic pollution of the species' gene pool and reduction of effective population size.

Nutrient (N, P, K) use efficiency and nitrogen balance in a bioenergy plantation of Populus deltoides clone Lux in San Piero A Grado (Pisa), Italy

Energy crops have proved to be a viable alternative to fossil fuels. However, high biomass production always means that large quantities of nutrients from the soil are removed at harvest. The goal of this work was to estimate nutrient (nitrogen, phosphorous, potassium) use efficiency (NUE) and nitrogen balance in an eight-year-old Populus deltoides clone Lux, short rotation forestry under two cutting cycles, every two (biennial) and three (triennial) years, carried out under Mediterranean climate conditions. Results indicate that NUE, for all the analyzed elements, contained variations with slightly higher values for nitrogen and phosphorous in the triennial cycle. Although poplar cultivation has a positive nutrient efficiency, in terms of nitrogen, there is significant loss of this element in the crop cycle.

Sex-specific responses of Populus deltoides to combined salinity and calcium under waterlogging conditions

In this study, we investigated the sex-specific ion uptake and physiological and biochemical responses to combined salinity and calcium treatments of male and female Populus deltoides under waterlogging conditions. Results indicate that both P. deltoides clones were sensitive to salinity and calcium. Under well-watered conditions, salinity stress could especially increase the Na content in female P. deltoides clones, whereas salinity and calcium could increase the K and Ca content in male clones. Waterlogging could evidently stimulate Na content in leaves under salinity, especially in female P. deltoides clones. However, waterlogging had no visible effects on the amount of Ca absorption between the two clones under abundant calcium conditions. The physiological and biochemical responses to combined salinity and calcium exceeded the effects of salinity or calcium individually. However, no significant difference was observed, hence indicating the similar responses of male and female P. deltoides clones. The lower Na content and Na:Ca ratio, and the higher K and Ca content in male clones suggest that the male clones could maintain ion homeostasis better than the female clones. The sex-specific differences in net photosynthetic rate, intercellular CO2 concentration, effective quantum yield of photosystem II, photochemical quenching coefficient, non-photochemical quenching coefficient, photosynthetic electron transport rate, content of superoxide anions, hydroxyl radicals, H2O2, soluble protein, and activities of superoxide dismutase under certain conditions suggest that female P. deltoides clones are more sensitive to salinity, calcium, and the combination of both than their male counterparts.

Modulation of Morpho-Physiological Responses in Populus deltoides by Elevated Carbon Dioxide and Temperature

AbstractRising atmospheric carbon dioxide (CO2) and temperature alter gene-expression arrays commensurate with physio-morphological changes, resulting in issues of adaptation, growth patterns, and productivity of terrestrial vegetation. An experiment was conducted to investigate the adaptive response of Populus deltoides clone G48 to the combined effect of elevated CO2 and temperature inside open-top chambers. The elevated CO2 and temperature acted as environmental cues to help express upregulated/downregulated genes involved in important metabolic pathways. As a result, P. deltoides exposed to the elevated CO2 and temperature developed adaptation to undo the effect by enhancing gaseous exchange, transpiration, and carbon assimilation and partitioning as observed on 180 days after treatment. The elevated conditions significantly enhanced stomatal density and size on adaxial/abaxial leaf surfaces, chlorophyll b that augmented photosynthesis, stomatal conductance, transpiration, and internal CO2, but decreased instantaneous and intrinsic water-use efficiency. These stimulated biomass accumulation in root, stem, and leaves. Hence, the elevated conditions of CO2 and temperature operate at the gene-expression level that acts pleiotropically for reinforcement of photosynthetic apparatus, morphological amendment for accelerated gaseous exchange, and finally growth and biomass improvement, supporting adaptive plasticity of clonal planting stock of the species to future climatic change and global warming.

Root traits and rhizosphere processes reflect differential phosphorus acquisition strategies in contrasting Populus clones

Soil phosphorus (P) availability and its distribution influence plant growth and productivity. To evaluate strategies that allow genotypes to be efficient under variable P environments, we planted six hybrid Populus deltoides clones belonging to the section Aigeiros (Aig), LL1, LL9, NL351, NL35, NL1388 and NL895, to three growth conditions in a greenhouse experiment, including low P, a high homogenous P supply and a high heterogeneous P supply. Functional traits, including foliar and root traits as well as rhizosphere processes, were measured. Large genotypic variation in shoot biomass and leaf P concentration was found in response to the P supply level and pattern. Compared with no P supply, LL1, LL9 and NL895 had a greater root length, biomass and P concentration in leaves under a homogenous P supply, while growth traits of NL351, NL35 and NL1388 were not significantly affected. A heterogeneous P supply enhanced the shoot biomass of LL1 and LL9. The root proliferation of LL1 and LL9 in P-rich patches was related to increased P acquisition in leaves. By contrast, a heterogeneous P supply did not enhance the biomass accumulation and the morphological plasticity of roots in other four genotypes, NL351, NL35, NL895 and NL1388, in P-rich patches. We found that functional traits or rhizosphere processes under low P could predict high P performance in Populus clones. Genotypes with a higher specific root length under low P can accumulate a larger biomass under a homogenous P supply. Conversely, high acid phosphatase concentrations decreased the positive impact of a heterogeneous P supply on a genotype’s performance. Our results provide implications and applications for silviculture and forest management.

Investigation of rooting and growth characteristics of poplar clones in hydroponic and soil cultures

In this study, rooting and growth characteristics of different poplar clones from six species including Populus deltoides Bartram ex Marshall clone Lux, Populus nigra subsp. betulifolia (Pursh) W. Wettstein clone 17/13, Populus euramericana (Dode) Guinier clone 561/41, P. deltoides clone Samsun, Populus alba Linnaeus clone 49/9, Populus caspica (Bornmüller) Bornmüller, and Populus euphratica Olivier in hydroponic and soil cultures have been evaluated. In hydroponic culture, poplar cuttings were grown in plastic tanks and in soil culture, poplar cuttings were planted into plastic pots with 12 replications for each clone. The pot experiment was a Complete Randomized Design. Root length, stem diameter, stem height, and root and shoot dry matter of poplar plants were studied in hydroponic culture after 84 days and in soil culture three times at 6, 12, 18 weeks in 2017. In hydroponic culture, the cuttings of P. deltoides Lux and P. nigra betulifolia 17/13, and of P. deltoides Samsun and P. euphratica were among the first and last clones that rooted, respectively. Also, the lowest rate of rooting was observed in P. deltoides Samsun and P. euphratica clones. The highest values of all parameters except root length were obtained in P. euphratica. The highest root length and stem diameter were observed in clones of P. deltoides Lux, P. nigra betulifolia 17/13, P. euramericana 561/41, and P. deltoides Samsun. In soil culture, P. deltoides Lux, P. nigra betulifolia 17/13, and P. alba 49/9 showed the highest percentage of rooting compared to the other clones at the first measurement. All the clones except the clone of P. euphratica reached above 40 cm root length in each of the three measurement periods. The highest stem diameter, stem height, and shoot dry matter were obtained in clone of P. deltoides Lux and root dry matter in clone of P. alba 49/9.

Assessment of cadmium tolerance and phytoextraction ability in young Populus deltoides L. and Populus × euramericana plants through morpho-anatomical and physiological responses to growth in cadmium enriched soil

Abstract: Fast growing woody plants represent effective tools for cadmium (Cd) extraction during remediation of low to medium Cd contaminated soils. Poplars are good candidates for this task because of their rapid growth rate, high biomass yield, and adaptability, as well as the availability of well-characterized clones/ genotypes with various anatomical and physiological traits. The present study evaluates the potential of Populus deltoides (clone B-81) and Populus × euramericana (clone Pannonia) for phytoremediation of Cd contamination in soil. Poplar clones were analyzed for (1) plant growth response to Cd contamination, (2) Cd accumulation, translocation, and partitioning between plant organs, and (3) morphological, anatomical and physiological responses to Cd stress as a function of biomass production. Plants were cultivated in soil moderately contaminated with Cd (8.14 mg kg-1 soil) under semi-controlled conditions for six weeks. Our results suggest that P. × euramericana and P. deltoides clones respond differently to Cd contamination. Biomass production and morphological characteristics were more negatively affected in P. × euramericana than in P. deltoides plants. However, most examined leaf structural parameters were not significantly affected by Cd. In most cases, photosynthetic characteristics and gas exchange parameters were affected by Cd treatment, but the levels and patterns of changes depended on the clone. High tolerance to applied Cd levels, as estimated by the tolerance index, was observed in both clones, but was higher in P. deltoides than P. × euramericana (82.2 vs. 66.5, respectively). We suspect that the higher tolerance to Cd toxicity observed in P. deltoides could be related to unchanged proline content and undisturbed nitrogen metabolism. Following treatment, 58.0 and 46.7% of the total Cd content was accumulated in the roots of P. × euramericana and P. deltoides, respectively, with the remainder in the stems (18.2 and 39.9%) and leaves (23.8 and 13.4%). In summary, P. deltoides displayed better phytoextraction performance under Cd exposure than P. × euramericana, suggesting its potential not only for Cd phytostabilization, but also phytoextraction projects.

Genetic transformation of Populus nigra X P. deltoides (black poplar, clone Gradizka)

Aim. To carry out genetic transformation of poplar Populus nigra x P. deltoides clone Gradizka with the model gene construct pCB002 carrying selective gene of kanamycin resistance and marker gene of β-glucuronidase. Methods. Genetic transformation was performed with the using leaf, stem and petiole poplar explants. Transformants were selected on the medium with kanamycin, and transgene was identified by polymerase chain reaction (PCR) and histochemical GUS assay. Results. Successful transformants selected on kanamycin media were confirmed by the presence of PCR-product for the gene nptII with the length 700 bp, and gus gene expression was also observed. Conclusions. Protocol for genetic transformation of P. nigra x P. deltoides clone Gradizka established here will be used for poplar genetic modification to create new clones with commercially important traits. Keywords: genetic transformation, Populus sp., microclonal propagation.

Physiological and molecular responses to heavy metal stresses suggest different detoxification mechanism of Populus deltoides and P. x canadensis

Plants have divergent defense mechanisms against the harmful effects of heavy metals present in excess in soils and groundwaters. Poplars (Populus spp.) are widely cultivated because of their rapid growth and high biomass production, and members of the genus are increasingly used as experimental model organisms of trees and for phytoremediation purposes. Our aim was to investigate the copper and zinc stress responses of three outstanding biomass producer bred poplar lines to identify such transcripts of genes involved in the detoxification mechanisms, which can play an important role in the protection against heavy metals. Poplar cuttings were grown hydroponically and subjected to short‐term (one week) mild and sublethal copper and zinc stresses. We evaluated the effects of the applied heavy metals and the responses of plants by detecting the changes of multiple physiological and biochemical parameters. The most severe cellular oxidative damage was caused by 30μM copper treatment, while zinc was less harmful. Analysis of stress-related transcripts revealed genotype-specific differences that are likely related to alterations in heavy metal tolerance. P. deltoides clones B-229 and PE 19/66 clones were clearly more effective at inducing the expression of various genes implicated in the detoxification process, such as the glutathione transferases, metallothioneins, ABC transporters, (namely PtGSTU51, PxMT1, PdABCC2,3), while the P. canadensis line M‐1 accumulated more metal, resulting in greater cellular oxidative damage. Our results show that all three poplar clones are efficient in stress acclimatization, but with different molecular bases.

Interpreting genotype‐by‐environment interaction for biomass production in hybrid poplars under short‐rotation coppice in Mediterranean environments

AbstractUnderstanding genotype × environment interaction (GEI) is crucial to optimize the deployment of clonal material to field conditions in short‐rotation coppice poplar plantations. Hybrid poplars are grown for biomass production under a wide range of climatic and edaphic conditions, but their adaptive performance in Mediterranean areas remains poorly characterized. In this work, site regression (SREG) and factorial regression mixed models are combined to gain insight into the nature and causes underlying GEI for biomass production of hybrid poplar clones. SREG addresses the issue of clonal recommendation in multi‐environment trials through a biplot representation that visually identifies superior genotypes. Factorial regression, alternatively, involves a description of clonal reaction to the environment in terms of physical variables that directly affect productivity. Initially, SREG aided in identifying cross‐over interactions that often involved hybrids of different taxonomic background. Factorial regression then selected latitude, mean temperature of the vegetative period (MTVP) and soil sand content as main site factors responsible for differential clonal adaptation. Genotypic responses depended strongly on taxonomic background: P. deltoides Bartr. ex Marsh. × P. nigra L. clones showed an overall positive sensitivity to increased MTVP and negative sensitivity to increased sand content, whereas the opposite occurred for P. trichocarpa Torr. & Gray × P. deltoides clones; the three‐cross hybrid [(P. deltoides × P. trichocarpa) × P. nigra] often displayed an intermediate performance. This information can contribute toward the identification and biological understanding of adaptive characteristics relevant for poplar breeding in Mediterranean conditions and facilitate clonal recommendation at eco‐regional level.

Agrobacterium-mediated genetic transformation of Populus deltoides marsh clone G48 with gus and npt-II genes

Agrobacterium-Mediated Genetic Transformation of Populus deltoides Marsh Clone G48 with gus and npt-II Genes The present investigation had been carried out to standardize a protocol for Agrobacterium- mediated gene transfer in Populus deltoides Marsh. Clone G48 using petiole explants. Reproducibility of already standardized regeneration protocol for clone G48 had been evaluated. High frequency shoot regeneration (72%) from petiole explants was obtained on MS medium supplemented with 0.5 mg l-1 BAP, 0.2 mg l-1 IAA and 15 mg l-1 adenine sulphate. Root regeneration (100%) in in vitro developed shoots was obtained on MS medium supplemented with 0.1 mg l-1 IAA. Increasing concentrations of kanamycin (10-50 mg l-1) were given to find out the minimum dose of kanamycin required for the selection of putative transformed cells during genetic transformation. It was observed that a doze of 50 mg l-1 kanamycin inhibited callus formation and shoot regeneration and the explants turned brown and started dieing. This concentration of kanamycin would be the most useful for selection of npt-II gene transformed petiole cells/ tissues. Disarmed Agrobacterium tumefaciens LBA 4404 strain containing a reporter β-glucuronidase (gus) gene in binary vector pBI 121 along with kanamycin resistance gene (npt-II) was used for genetic transformation experiments. Only the transformed cells/ shoots were able to grow on selective shoot regeneration medium containing 50 mg l-1 kanamycin, whereas control explants did not survive. Regenerated putative transgenic shoots were subjected to transient gene expression analysis using spectrophotometric GUS assay and were found positive. This genetic transformation protocol will provide a platform for genetic manipulation of P. deltoides clone G48 for incorporation of genes governing various silviculturally important traits in future....

Short-term and long-term effects of weed control and fertilization on growth and wood anatomy of a Populus deltoides clone

Aims of study: The short- and long-term effects of weed control and fertilization on growth and wood anatomy of 10-y-old Populus deltoides were investigated. Weed control and fertilization usually leads to an increase the growth rate of trees, and consequently, a possible modification in the quality of produced wood.Area of study: We analyzed trees from an experimental plantation in Buenos Aires, Argentina (34°50’ S Lat; 60°30’ W Long).Methods: 32 trees from three treatments: mechanical weed control (M), chemical and mechanical weed control (CHM) and fertilized plus chemical and mechanical weed control (CHM-F) were analyzed. Basal area, fibre morphology, cell wall area and vessel size were measured in the growth ring 1, 3 and 10.Results: differences on wood anatomy among treatments were mainly observed at the third year (short-term effect). Long-term negative effects were not observed. Fertilized trees had greater proportion and quality of wood closer to pith.Research highlights: fibre and vessel differences seen in CHM and CHM-F compared to controls in year 3 could be interpreted as evidence of maturation in cambial development (thicker, longer and wider fibres and greater vessels). The CHM-F treatment had a greater proportion of wood that showed characteristics of more mature wood.Key words: silvicultural treatment; wood quality; fibre properties; vessels; poplar; cambial maturity.

Comparison of Biomass and C Storage in Three Promising Fast Growing Tree Plantations under Agroforestry System in Sub-humid Tropics of Chhattisgarh, India

The anthropogenic activities are alarmingly increasing the concentrations of CO2 in the atmosphere leading to the climate change. Agriculture ecosystem especially tropical agriculture is most vulnerable to climate change posing a serious threat on food, nutritional security and livelihoods of poor farming communities. Agroforestry technologies indeed offer viable opportunity to mitigating the atmospheric accumulation of CO2 and other Greenhouse gases, and potential for transforming to resilient farming systems and further help smallholder farmers of many tropical countries like India for adapting to climate change. However, the magnitude of C sequestration in many agroforestry systems is still unknown, which primarily depends on the choice of tree species and managerial practices. The present study corresponds to a part of the long term project on Gmelina arborea, Populus deltoides and Ceiba pentandra based agroforestry systems evaluated for C storage potentials in sub-humid tropics Chhattisgarh, India. At 5 years age, total biomass varied from 12.9 Mg ha-1 to 25.1 Mg ha-1 in C. pentandra, while 9.9 Mg ha-1 to 21.4 Mg ha-1 in G. arborea. The biomass was greater under narrow tree spacing. A significant growth and biomass variation was also exhibited by P. deltoides clones, where the total biomass ranged from 48.5 Mg ha-1 to 62.2 Mg ha-1. At 5 years age, total C storage in G. arborea stands ranged from 4.3 to 9.4 Mg ha-1, P. deltoides from 22.5 to 30.1 Mg ha-1 and C. pentandra from 4.5 to 10.1 Mg ha-1. Soil organic C significantly enhanced under agroforestry system. Soil organic C in G. arborea stands increased from 6.8% to 11.9%, P. deltoides from 12.7% to 20.6%, and C. pentandra from 5.5% to 14.5% under different treatments. P. deltoides showed the greater potential for C sequestration than G. arborea and C. pentandra under agroforestry system. Clones 65/27 and D121 of P. deltoides were found outstanding and suggested to adopt under agroforestry. Soybean and wheat yields were decreased under agroforestry systems, which advocate introducing appropriate tree management practices to improve the complementarity to exploit synergies between tree and crop components. The paper discusses the management implications and strategies for sustainable tree-crop production and improving C sequestration under agroforestry systems for mitigating the climate change.

Anatomical, biochemical and morphological responses of poplar Populus deltoides clone Lux to Zn excess

The present study investigated the effect of excess Zn on growth and development of poplar (Populus deltoides Bartr. ex Marsh.) clone Lux. Although Zn did not greatly influence the production of plant biomass, the concentration of Zn in leaf tissues was significantly increased. This corresponds with shifted development of final stage of apoplasmic barriers in Zn-treated roots more distant from the root apex when compared with control roots. In the same time, various symptoms of Zn toxicity have been observed at anatomical and ultrastructural level, both in roots and in leaves. Cellular localization of Zn in roots by cryo-SEM and energy-dispersive X-ray microanalysis revealed that Zn is accumulated mostly in the root peripheral tissues and decreased toward to the central cylinder. Increased uptake and accumulation of Zn in leaves without visible reduction of growth makes this particular poplar clone an interesting candidate for future study aimed to phytoremediation of Zn-polluted sites.

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Effects of Weed Control and Fertilization on Wood and Chemi-mechanical Pulp Properties of a Populus deltoides Clone

Weed control and fertilization usually lead to an increase in the growth rate of trees and, consequently, to a possible modification of the quality of the wood and its end products. The effect of weed control and fertilization practices were determined on tree growth parameters, wood density, fiber weight, fiber length, and chemical wood composition, as well as the chemi-mechanical pulp properties, for 8-year-old Populus deltoides `Delta Gold´ grown in Argentina. Four treatments belonging to a randomized complete block design trial were analysed: no weeding after planting (C), mechanical weed control (M), chemimechanical weed control (CHM), and fertilized + chemimechanical weed control (CHM-F). Soda-sulfite chemi-mechanical pulps were produced from said trees. Handsheets were prepared from the pulps, and their physical, mechanical, and optical properties were determined following international standards. Several wood and pulp properties were influenced by the studied silvicultural practices. In the context of this study, silvicultural treatments applied to Populus deltoides ‘Delta Gold’ (formerly ‘Stoneville 66’) trees can be applied to increase productivity (volume and fibrous output) without detrimental consequences to wood and pulp properties, except for a slight reduction in brightness.