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New Forests
Journal Prestige (SJR): 1.033  Citation Impact (citeScore): 3 Number of Followers: 2  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1573-5095 - ISSN (Online) 0169-4286 Published by Springer-Verlag  [2469 journals]
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- Climate change and the growth of Amazonian species seedlings: an
ecophysiological approach to Euterpe oleracea-
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Abstract: Abstract Climate change threatens many native species from the Amazon Forest. Among the endangered species is the Açaí (Euterpe oleracea), which is a species with great national and international interest, due to the nutritional benefits and medicinal properties of its fruits. However, there is still no information on the ecophysiological responses of Açaí to climate change. Thus, the objective of this work was to evaluate the effect of increased temperature and CO2 concentration change on the ecophysiology of Açaí seedlings. To do so, Açaí seedlings were subjected, for 90 days, to three different climatic scenarios: current Amazon; RCP4.5 (current average temperature in the Amazon + 2.5 °C and 538 ppm of carbon dioxide concentration i.e. CO2); and RCP8.5 (+ 4.5 °C and 936 ppm of CO2 concentration). In addition, two irrigation levels were applied within each climatic scenario: seedlings maintained at 90% (not stressed) and 40% (stressed) of the water holding capacity of the substrate. Gas exchange, water status, fluorescence parameters, enzymatic antioxidants activity and dry matter production were evaluated. High CO2 concentration enhanced Açaí gas exchange (increasing CO2 assimilation), regardless of substrate water availability and temperature. However, high temperature and high vapor-pressure deficit reduced quantum yield and increased the minimum fluorescence and enzymatic antioxidants activity. With that, Açaí seedlings did not convert the additional assimilated carbon (due to higher CO2 concentration) into biomass, showing decreased total dry mass accumulation for RCP4.5 and RCP8.5 climate scenarios. Our results indicated that the positive impacts of increased CO2 concentration to gas exchange may not offset the negative impacts of increased air temperature and VPD to Açaí growth.
PubDate: 2022-05-12
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- Large-scale assessment of artificially coated seeds for forest
regeneration across Sweden-
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Abstract: Abstract We report the results of two years’ field performance of Scots pine (Pinus sylvestris) seedlings regenerated using artificially coated seeds. The coated seeds were used for regeneration on 12 clearcut sites, covering a 1000 km latitudinal gradient across Sweden. The coating was either combined with arginine-phosphate fertilizer (10 mg N per seed) or had no additions. Interactions with environmental variables associated with sites were also assessed. Coated seeds were deployed in May–June 2017 and surveyed in August–September of 2018 and 2019. After two years, the mean establishment rate of seedlings from coated seeds was 56 ± 4% across the 12 sites. The fertilizer addition did not affect survival, and the biomass response to fertilizer varied significantly between sites. Maximum precipitation and wind speed during the first six weeks after deployment were correlated with seedling survival, regardless of fertilization treatment. Establishment increased with increasing precipitation and decreased with increasing wind speed. This highlights the importance of initial weather conditions for the seeds’ establishment. Our data suggest that Scots pine regeneration using coated seeds can be practiced in boreal forests, but also that the method is sensitive to the weather conditions at the time of deployment of the seeds.
PubDate: 2022-05-10
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- Correction to: Influence of heterozygosity and competition on
morphological tree characteristics of Quercus rubra L.: a new
single‑tree based approach-
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PubDate: 2022-05-01
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- Drought responses of an exotic tree (Eriobotrya japonica) in a tropical
cloud forest suggest the potential to become an invasive species-
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Abstract: Abstract Eriobotrya japonica is a non-native tree expanding in secondary forests and threatening the tropical montane cloud forest of central Veracruz, Mexico. Our objective was to investigate whether E. japonica has invasive potential by examining morphological and physiological functional traits in response to drought events. We did field surveys in a cloud forest reserve, and determined responses to experimental drought on germination, growth, morphological (leaf area, specific leaf area, thickness, and chlorophyll content) and physiological (hydraulic conductivity, maximum photosynthesis, and stomatal conductance) functional traits. Eriobotrya japonica adults, saplings, and seedlings were dominant in secondary forest, but scarce in mature forest. In lab, cumulative germination curves were similar across treatments (low–high temperatures; drought, water) while in the forest there was a delayed germination in drought treatment, though ultimately total germination was similarly high in the lab and field. Growth of seedlings was higher in light gaps than in the understory. However, leaf area was similar across treatments, SLA was lower, and thickness and chlorophyll content were higher in the gap-drought treatment. Physiological traits reinforced that E. japonica is highly drought resistant as demonstrated by avoidance of losses in hydraulic conductivity and high levels of carbon fixation. In a drought experiment, it took over 2 months to reach injurious losses in hydraulic conductivity. This study demonstrated that germination, growth, and physiological maintenance will all be unaffected in drought conditions and we concluded that E. japonica has potential to become an invasive alien species.
PubDate: 2022-05-01
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- Large-scale historical afforestation failure with Pinus cembra in the
Swiss Prealps-
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Abstract: Abstract Between the nineteenth and early twentieth centuries, large-scale afforestation projects were undertaken in the Swiss Prealps. The Swiss stone pine (Pinus cembra L.), an emblematic alpine tree with important economic potential, conservation value and ecological relevance, was one of the species used in these afforestation efforts. We investigated the distribution and site characteristics of all known natural populations and planted stands in the canton of Fribourg (Switzerland). Between 1885 and 1952, artificial afforestation was carried out in the mountainous regions of the canton of Fribourg. Nearly 450,000 seedlings of P. cembra were planted. One century later, only approximately 650 trees survived (0.15% of all planted trees). Moreover, no natural regeneration can be observed in the afforested stands. Since no known harvest activities were undertaken in these planted stands, the whole afforestation campaign of P. cembra in the canton of Fribourg can be described as a failure. Possible causes are investigated and discussed. In this region, P. cembra occurs naturally only in particular microrefugia with markedly rough topography. We argue that the lack of knowledge or consideration of the ecology of the species at a local scale can be an important factor leading to this failure. In the actual context of large-scale afforestation projects anticipating and mitigating the negative effects of global warming, our study highlights the importance of a precise understanding of species ecology and regional conditions.
PubDate: 2022-05-01
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- Morphological and physiological parameters influence the use efficiency of
nitrogen and phosphorus by Eucalyptus seedlings-
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Abstract: Abstract Morpho-physiological characteristics in Eucalyptus species can determine N (NUE) and P (PUE) use efficiency and, consequently, the plant's responses to fertilization. The study aimed to evaluate whether morphological and physiological characteristics of seedlings from Eucalyptus species affect the N and P use efficiency. For this, in a greenhouse, Eucalyptus grandis (GPC 23) and Eucalyptus saligna (32864) clones were grown in Hoagland nutrient solution for 21 days, followed by N and P restriction in CaSO4 solution 0.1 mol L−1 during 15 days. Morphological parameters from shoot and root system, dry mass of organs, photosynthetic pigments concentration, and chlorophyll a fluorescence of Eucalyptus species were evaluated, and NUE and PUE were calculated. Eucalyptus grandis presented the highest NUE and PUE values. The highest surface area, volume, and roots length values contributed to these results, justifying the highest dry mass production from leaves, stem, roots, and plant. Eucalyptus saligna presented the lowest NUE and PUE values, which negatively influenced photosynthesis (higher F0 values and lower concentrations of photosynthetic pigments). Root morphological parameters had a strong relationship with NUE and PUE and can be used to select Eucalyptus species, and breeding programs, as they can predict the ability of development of Eucalyptus species under low N and P availability.
PubDate: 2022-05-01
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- Biochemical and anatomical features of adventitious rhizogenesis in apical
and basal mini-cuttings of Ilex paraguariensis-
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Abstract: In order to better understand the physiological and technical aspects of yerba mate vegetative propagation, the present study sought to evaluate the rhizogenic capacity of apical and basal mini-cuttings from different genotypes (named A3, A7, F1 and F2) and the possible relationships between rooting and specific biochemical and anatomical aspects of the species. After 90 days under greenhouse conditions, the following variables were assessed: mini-cuttings rooting percentage, number of roots, roots length, callogenesis, mortality, sprouting and leaf retention. Mini-cuttings samples were collected at the time of planting and after 90 days in the rooting environment in order to investigate the aspects related to stem and roots anatomy as well as the levels of phenolic compounds (PC) and the activities of peroxidade (POD) and polyphenol oxidase (PPO) enzymes. Genotype A3 presented the best rooting performance (65.6% rooting) while F2 had the lower rooting rates (24.5%). Apical and basal mini-cuttings did not differ regarding rooting associated variables. Both mini-cuttings types and the four genotypes showed identical anatomical features, with no evident mechanical barriers to roots emission. Despite specific differences on POD, PPO and PC activities/contents as influenced by topophysis, genotype and/or their interaction, no direct relationship could be stated between the biochemical features at the time of planting or 90 days after and the overall rooting performance of yerba mate the mini-cuttings. The present study not only provides valuable information on technical aspects of yerba mate propagation but also presents insights in the physiological and anatomical traits of adventitious rhizogenesis in this species. Graphic abstract
PubDate: 2022-05-01
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- Simulating the canopy photosynthesis of Qinghai spruce (Picea crassifolia
Kom.) in the Qilian Mountains, Northwestern China-
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Abstract: Abstract Qinghai spruce (Picea crassifolia Kom.) forests play a key role in the carbon sequestration in the Qilian Mountains, Northwestern China. Carbon sequestration is closely related to canopy photosynthesis, which greatly depends on the leaf-level photosynthesis. Quantifying the magnitude of canopy photosynthesis will improve the modeling of forest carbon cycling. Although biochemical models have been widely used to estimate primary production, the effects of canopy partition on the photosynthetic rates and its feed-backs into the carbon cycle are generally not represented. In this study, the difference and connection between the leaf gas exchange indices in the different canopy partitions and the diameter at breast height (DBH), tree height (H), crown diameter (CD), and living under branch height (BH) were determined, and a multiple linear regression model was explored. This study was performed to develop a regression model to link morphological and physiological characteristics to canopy photosynthetic rate. The classification methods improved the working efficiency, fitting performance, and prediction accuracy compared with the classical method. The classified DBH method exhibited the best fitting performance, because it had the highest determination coefficient (R2 = 0.9060). The photosynthetic model of the spruce canopy with the aforementioned factors produced a good simulation (R2 = 0.9773) and provided data support to further estimate the carbon budget and primary net productivity of the spruce canopy. The developed model was also very useful for updating and modifying forest base maps and registries of spatial distribution of biomass and carbon storage.
PubDate: 2022-05-01
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- Structure of genetic variation in vegetative phenology of Cedrela odorata
L.: implications for tree breeding-
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Abstract: Abstract The study of vegetative phenology is important to understand adaptation to different environments and potential trade-offs with growth traits. Crown leaf-out and leaf-fall phenology was evaluated on 168 open-pollinated families from 19 Cedrela odorata provenances in an eleven-year-old provenance/progeny trial established in the state of Veracruz, Eastern coast of Mexico. The objectives were: (a) to evaluate the extent of inter- and intra-population genetic variation of leaf phenology traits; (b) to examine the relationship between leaf phenology traits and climate variables at the population level; (c) to estimate the genetic relationships between leaf phenology and growth traits; and (d) to evaluate the accuracy, in terms of genetic control, of using alternative methods to measure leaf phenology in broadleaf trees. The study revealed significant genetic variation in leaf phenology traits both among and within populations. Leaf-out traits showed higher genetic variation than leaf-fall traits. A moderate to large genetic differentiation among Cedrela odorata populations was found; Qst values for leaf-out were 2–6 times higher than those for leaf-fall. Leaf-fall was primarily associated with mean annual temperature, while leaf-out and length of the leafless period were related to annual precipitation and the aridity index of the site of origin. Leaf phenology traits showed moderate to high genetic control (h2i = 0.12–0.67; h2f = 0.27–0.72). However, it was higher for leaf-out traits, so they might play a more important adaptive role. Genetic correlations between leaf phenology and growth traits allow selecting early flushing genotypes within populations to increase adaptation and growth, but caution should be taken when selecting among populations.
PubDate: 2022-05-01
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- Rehabilitation of Nothofagus pumilio forests in Chilean Patagonia: can
fencing and planting season effectively protect against exotic European
hare browsing'-
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Abstract: Abstract In forests affected by heavy fires and continuous grazing of exotic herbivorous mammal species, Nothofagus pumilio (lenga) cannot recover naturally. The main factors that hinder the natural recovery of these forests and the feasibility of native tree plantations are the exotic herbivorous pressure, like that produced by Lepus europaeus (European hare), and the environment degradation degree by anthropic disturbances. The objective of this study was to evaluate different plantation efforts to recover N. pumilio forests degraded by fires in Chilean Patagonia. The plantation actions also included wire fences for sapling protection in 100 ha, where 60 ha were established during autumn (May 2012), and 40 ha were established during spring (October 2012). In March 2013 we recorded the height annual growth (cm year−1), the section browsed at each sapling, the modification of plant form (number of new branches), and the vigor expression. We evaluated the data using one- and two-way ANOVAs, Cohen’s d effect size, and chi-square analyses. We measured a total of 872 plants, where 42% presented damages caused by European hare browsing. These results indicated that the wire fences were not completely useful to stop the damage on saplings (Cohen’s d effect size = < 0.2). We also found that autumn plantations were more susceptible to damage than those established during spring. European hares predominantly browsed on a particular sapling section: the apical buds. As a consequence, the browsed saplings had lower height growth than undamaged ones. These outputs highlight the need to explore and implement alternative actions for the rehabilitation of these degraded deciduous forests, to achieve the objectives of sustainable management or to recover the natural ecosystem functions.
PubDate: 2022-05-01
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- Solid shelter tubes alleviate summer stresses during outplanting in
drought-tolerant species of Mediterranean forests-
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Abstract: Abstract The effect of shelter tubes on plant performance has been widely studied. Although, the role of shelter tubes in alleviating the effects of drought and high-irradiance stresses during seedling establishment has been less studied than its effect on survival. The present study compares the effects of shelter tubes with different light transmissivities (Lt) on survival and morpho-physiological responses of two coexisting tree species (drought-tolerant Quillaja saponaria and relatively more drought-sensitive Maytenus boaria) of the Chilean matorral during an exceptionally dry and warm growing season (2014–2015). Two-year-old seedlings were randomly assigned to shelter tubes differing in Lt (20, 40, 60, 80%) or to a control (no shelter, Lt 100%) at field conditions. Survival was measured monthly, while shoot and root biomass, root length, pre-dawn xylem water potential, and non-structural carbohydrate concentration (NSC) were measured 8 months after transplanting. Shelter tubes increased the seedling survival of Q. saponaria by 80–100% relative to the control conditions, where full mortality was observed by the end of the experiment. By contrast, M. boaria exhibited high mortality regardless of the presence of shelters, suggesting that tubes were ineffective to alleviate the summer-related stresses in this species. Xylem water potential of Q. saponaria seedlings was significantly lower at 80% Lt than at 40% Lt, where maximum values were observed. Also, at 40% Lt, plant height and root length were highest and shoot/root ratio the lowest. By contrast, no differences in NSC, stomatal conductance, and photochemical efficiency were observed among Lt treatments. We conclude that shelter tubes may alleviate summer stresses in drought-tolerant species such as Q. saponaria; hence, they appear to be effective reforestation ecotechnology under severe water limitations and high-irradiance stress imposed by the current drought and heatwaves conditions in central Chile.
PubDate: 2022-05-01
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- A model of coppice biomass recovery for mallee-form eucalypts
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Abstract: Abstract Planting mallee-form eucalypts amongst crops has the potential to remedy environmental degradation caused by land clearing in low rainfall regions, whilst also providing income through carbon-sequestration or periodic coppicing. Management options can be supported by models of biomass and coppice recovery, and this paper presents the first empirical coppice growth model for mallee eucalypts. Uncoppiced and coppiced belt-planted Eucalyptus polybractea, E. loxophleba and E. kochii were harvested and roots excavated to provide estimates of shoot and root biomass for analysis and model development. Allometric models of shoot biomass were appropriate for both uncoppiced and coppiced trees, but models of root/total biomass ratio for coppice depended on site quality and age, and could not be modelled allometrically. Mean root/total biomass proportions for uncoppiced trees were estimated (with standard errors) to be 0.38 (0.009), 0.50 (0.031), and 0.46 (0.021) for E. polybractea, E. loxophleba, and E. kochii respectively and were sensitive to site quality but insensitive to age. The time taken to regain pre-coppice shoot biomass was about half that of full pre-cut root/total biomass ratio recovery, and was affected by coppicing age and site quality. A conceptual model of coppice growth indicated that coppiced stands may produce more total biomass than uncoppiced stands of the same age.
PubDate: 2022-05-01
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- Natural hybridization in seed stands of seven Mexican Pinus species
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Abstract: Abstract Natural hybridization can manifest different evolutionary results, such as accelerating differentiation and facilitating speciation through the rapid origin of new biochemical compounds, physiological or morphological phenotypes that allow hybrid species to occupy new habitats, which for parental species would be inaccessible. However, these expectations are not always fulfilled, because natural hybridization between divergent populations can lead to inadequate or unviable hybrids and, therefore, lower forest stability and productivity. Using pure species Pinus arizonica, P. cembroides, P. durangensis, P. engelmannii, P. leiophylla, P. lumholtzii and P. teocote trees and their natural hybrids, this study aims to determine for the first time: (i) morphological differences between pure pine trees and their hybrids molecularly detected, (ii) differences in vigor between 1970 seeds from trees of pure pine species and their hybrid trees (hereinafter called pure and hybrid parents), (iii) differences in vigor between 3465 seedlings from 1421 pure and hybrid parents, and (iv) whether growth of seedlings of hybrid parents is differently associated to parent tree’s environmental conditions, than growth of seedlings of pure parents. The seedlings grew under equal nursery conditions. Our results show some significant differences in morphological traits between the seed trees of pure species and their respective putative hybrid seed trees, and in seed and seedling fitness indices. In contrast to the mean growth of seedlings of hybrid parents, the mean growth of seedlings from pure parents was significantly associated with the parent tree’s bioclimatic conditions studied (R2 = 0.70 vs 0.83). There were only some individuals that presented hybrid superiority.
PubDate: 2022-05-01
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- Root system adaptations represent untapped opportunities for forest tree
seedling improvement-
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Abstract: Abstract We reviewed approaches for combining genetic and cultural tools to solve challenges associated with the improvement of tree seedling root systems for enhanced survival and growth. Literature regarding sources of variation in root traits, relationships between root traits and seedling growth and survival, and root trait heritability estimates from published studies were used to illustrate the utility of combining myriad approaches to enhance the efficiency of tree seedling improvement programs. We found that: (1) evidence exists for genetic variation in numerous root traits, (2) root traits tend to have intermediate heritability on average, and (3) evidence supports the possibility of harnessing maternal effects to modify root traits at least temporarily. Across eight root traits from 11 studies, median family narrow-sense heritability estimates (h2) were intermediate (0.25 ≤ h2 ≤ 0.50) for root diameter, root count, root biomass, the ratio of root-to-stem dry biomass, and projected root area, and low (h2 < 0.25) for root length, specific root length, and the ratio of total belowground-to-aboveground dry biomass. Findings from this review suggest that plant improvement pipelines can be optimized to harness root trait variation due to genetics, maternal effects, and nursery cultural regimes. However, the following related gaps in the literature emerged as fundamental obstacles to progress: What is the duration of root system responses to stress conditioning treatments' Which root traits correlate best with seedling survival and thus should be prioritized for improvement' Is it possible to reliably harness variation in root traits resulting from maternal effects'
PubDate: 2022-04-27
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- Root system development and field establishment: effect of seedling
quality-
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Abstract: Abstract Root development is critical to successful establishment after seedlings are outplanted on a forest restoration site. There is an array of practices nursery practitioners and foresters use to ensure seedlings develop quality root systems to aid in outplanting success. To this end, a select number of topics are examined on how they effect root system quality and the linkage between these culturing practices (i.e., nursery root culturing practices), good root morphological and physiological quality and successful field establishment. The following discussion first describes why root development is critical for seedlings to avoid planting stress and successfully transition into field establishment. This is followed by reviewing the seasonality of root growth patterns, and how nursery cultural practices that create optimum levels of nutrients and non-structural carbohydrates affect root growth. Bareroot and container-grown stocktypes are discussed in relation to how their ability to grow roots affects seedling establishment. Lastly, nursery practices related to bareroot root culturing and container type selection for container-grown seedlings are examined on how they can affect seedling root form and field establishment. By focussing on these topics, the intent was to gain a renewed perspective on the importance of root system quality to ensure seedling establishment after outplanting on a forest restoration site.
PubDate: 2022-04-19
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- Oxalate oxidase transgene expression in American chestnut leaves has
little effect on photosynthetic or respiratory physiology-
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Abstract: Abstract The American chestnut (Castanea dentata) was a widespread foundation species before the spread of the chestnut blight (caused by Cryphonectria parasitica). Resistance to blight has been achieved by the genetic insertion of a single copy of an oxalate oxidase gene into the chestnut genome. Here, we assess potential transgene impacts on American chestnut physiology, with a focus on photosynthesis and respiration. We collected measurements of leaf respiration and photosynthetic capacity for transgenic (T) and non-transgenic (NT) sibling trees in two distinct experiments. Multiple measurements of photosynthesis (light and CO2 response curves) and foliar traits (leaf mass per unit area, foliar N concentration) were indicative of equally high rates of photosynthetic capacity across T and NT plants, with no significant differences between groups. Photosynthetic rates were equivalent between T and NT plants across two studies in two locations. We observed a modest stimulation of foliar dark respiration in T vs. NT plants (~ 5–15%) across a range of temperatures, but no change in foliar respiration in the light. The modest stimulation of dark respiration did not seem to be associated with an alteration in growth rate, as stem diameter and length were equivalent between T and NT types. Our findings suggest that there may be a minor impact of transgene expression on the respiratory physiology in some situations, but this effect is not likely to strongly impact the physiological ecology of this historically important species.
PubDate: 2022-04-19
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- Clones of non-pathological witches’ broom and normal crown from the same
trees in Pinus sibirica on common and separate rootstocks: how and why
David wins over Goliath-
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Abstract: Abstract Mutational witches’ broom (WB) is a local system of tree shoots with abnormally dense branching and slow growth that visually differs from the normal crown and is presumably caused by a dominant somatic mutation. In this study, we compared the growth of the mutant and normal clones from the same trees growing on different rootstocks and on different branches of the same rootstock to determine how a mutational WB affects a normal tree crown if they have the same starting position. We measured graft length, crown width, and stem diameter at the base of the graft in five pairs of 20-old mutant and normal clones originating from the same trees grafted on normal rootstock. The intrinsic capabilities of a witches’ broom are very limited. Single WB clones had 2.0–3.8-fold shorter stems, 1.5–2.0-fold lower crown width, and 1.2–2.0-fold lower stem diameter than single normal clones. When the mutant and normal clones grew together on a double-stem rootstock, mutant clones had approximately the same growth rate but easily suppressed normal crown clones. In this case, WB clones had 1.4–1.8-fold taller stem height, 3.0–4.0-fold higher crown width, and 2.5–4.0-fold higher stem diameter than normal crown clones due to the abnormally high attracting capacity of a WB. The more pronounced the specific traits in WB clones, such as reduced growth and increased branching, the more aggressive they behave relative to the normal crown to more quickly and strongly suppress growth. Characteristics of the WB, such as growth abnormality, aggressiveness relative to the normal crown, and reduced level of differentiation, make it more similar to a benign neoplasm.
PubDate: 2022-04-16
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- Correction to: Application of somatic embryogenesis for development of
emerald ash borer-resistant white ash and green ash varietals-
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PubDate: 2022-04-13
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- Asymmetrical copper root pruning may improve root traits for reforesting
steep and/or windy sites-
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Abstract: Abstract Our research demonstrates that plant material can be produced in the nursery with asymmetrical root systems, which may have utility for reforestation of difficult planting sites characterized by steep slopes and/or windy conditions. Such a root system can be generated using chemical root pruning by applying cupric carbonate (Cu) that can arrest the development of, or cause mortality to, root apical meristems resulting in the formation of new lateral roots with an overall increase in the biomass, length, and volume of the root system. Our objective was to investigate the effect of chemical root pruning on the morphological and architectural traits of adventitious roots produced by poplar cuttings (Populus nigra L.) grown in containers coated with Cu in various symmetrical (Side, Bottom, Side + Bottom) and asymmetrical (half side + half bottom) patterns. After six weeks, roots of the cuttings were extracted from different container depths (Top, Middle, and Bottom) and portions (non-coated, Cu-coated), and analyzed. The root systems reacted to all coating patterns by increasing length, biomass, volume, and average diameters, but magnitude of increase was further affected by depth. In particular, root growth was unaffected at the Top of the container, and length was the highest at the Bottom depth. The Middle depth had a significant increment in both biomass and volume. Also, the root population increased in diameter as a possible response to Cu exposure. Interestingly, in the asymmetrically coated containers this depth response in the non-coated portions was of higher magnitude than in the Cu-coated portions.
PubDate: 2022-04-13
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- Forest active restoration for silvopastoral use in Northwestern Patagonia:
relative importance of the nurse effect-
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Abstract: Abstract Ecological interactions, such as facilitation among plant species, has been identified as key for restoration actions. The stress-gradient hypothesis predicts that facilitation increases under harsh environments, but disturbance type and nurse shrub characteristics may modify this prediction. We aim at assessing the effect of two interacting factors (herbivory pressure and light availability) and palatability of the nurse shrub on the importance of nurse effect for active restoration of mixed evergreen forests of northern Patagonia (Argentina) for silvopastoral use. We planted Austrocedrus chilensis seedlings under two silvopastoral use intensities (higher and lower according to livestock seasonal movements) and under three micro-site treatments (palatable shrub, non-palatable shrub, inter-canopy), and evaluated survival and growth during three consecutive years. Under higher use intensity (increasing stress of light availability as desiccation risk and herbivory) we found contrasting effects of the nurse effect on seedling survival and growth, but the palatability of nurse shrub had no effect. Under higher use intensity, seedling survival was lower, while growth was higher. Higher values of seedling survival were found under low use intensity inter-canopy micro-site. Under high use, the presence of a nurse shrub is important for summer seedling survival, indicating its role in avoiding desiccation. The same occurred for winter seedling survival, where a nurse shrub may decrease mainly trampling risk. We highlight the importance of considering the interaction between disturbance factors for the net outcome of the nurse effect in active restoration actions, as it may allow for diverse actions to restoration.
PubDate: 2022-04-10
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