Robinia Pseudoacacia Research Articles

Enhancing Cd and Pb tolerance of Robinia pseudoacacia (black locust) by regulating antioxidant defense system, macroelement uptake and microstructure.

Woody plants had received considerable attention for the phytoremediation of heavy metal-contaminated soil. This study aimed to investigate the changes in antioxidant enzyme activity, macroelement uptake, and microstructure of the woody plant Robinia pseudoacacia (black locust) for the phytoremediation of cadmium (Cd) and lead (Pb) co-contaminated soil based on dynamic sampling. The results showed that black locust demonstrated strong tolerance in Cd and Pb co-contaminated soil. After 30-120 d of cultivation, the activities of superoxide dismutase (SOD), peroxidase (POD), and the macroelement (K and Ca) content in plant leaves significantly declined in response to Cd and Pb. However, after 160 d of cultivation, the antioxidant enzyme activities, chlorophyll, sulfhydryl, and soluble protein contents, as well as Ca and Mg content in plant leaves were returned to normal levels under the 40mg·kg-1 Cd and 1000mg·kg-1 Pb contaminated soil (CdPb3). Meanwhile, K content in plant leaves under the CdPb3 treatment was significantly (P<0.05) increased by 68.9% compared to the control. Cd and Pb was primarily accumulated in black locust roots. Scanning electron microscope (SEM) analysis indicated that the sieve tubes in the roots and stems of plant might block the transport of Cd and Pb. Transmission electron microscope (TEM) analysis indicated that the number and volume of osmiophilic particles in plant leaves were increased and the cell walls were thickened in response to Cd and Pb stress. Path analysis further indicated that the growth of plant was related to macroelements uptake and physiological change (photosynthesis, antioxidant enzyme activity, and chelation). Thus, black locust could effectively regulate the antioxidant defense system, macroelement absorption, and microstructure to enhance plant tolerance to Cd and Pb stress. Moreover, black locust could maintain the normal urease, acid phosphatase, and sucrase activities in the Cd and Pb co-contaminated soil. These findings suggested that black locust could be considered as a useful woody plant for the phytostabilization in Cd and Pb-contaminated soil.

Identification of standing dead trees in Robinia pseudoacacia plantations across China’s Loess Plateau using multiple deep learning models

Identification of standing dead trees in Robinia pseudoacacia plantations across China’s Loess Plateau using multiple deep learning models

Water consumption turning point for Robinia pseudoacacia occurs at its middle stand age

Water consumption turning point for Robinia pseudoacacia occurs at its middle stand age

Analysis of Wood Density to Compare the Amount of Accumulated Carbon Dioxide in the Stems of Selected Non-Native Tree Species in Poland

One of the priorities in European policy is the greater use of wood. In this context, it is important to know the total amount of CO2 absorbed by the tree and accumulated in the wood. In the timber industry, butt logs are mainly processed. The aim of this study is to analyze diameter at breast height (DBH), wood density (WD), and the amount of CO2 in grand fir (GF), Douglas fir (DF), northern red oak (NRO), and black locust (BL) wood. The DBH and bark thickness were measured, and cores were taken to study WD and calculate the amount of CO2. Analyses were conducted in three age classes of trees. It was found that in the youngest age class, DF had a significantly larger DBH compared to NRO and BL, and GF had a significantly larger DBH compared to NRO. The wood density of coniferous species was significantly lower compared to broadleaved species. DF absorbed the most CO2. In Class III, DF had significantly larger DBH and significantly lower wood density compared to NRO and BL. DF absorbed significantly more CO2 compared to NRO. In Classes IV and V, DF had larger DBH compared to NRO and lower wood density. The amount of CO2 absorbed by both species was similar. Taking into account the amount of absorbed CO2, the durability of the wood, and aspects related to sustainable forest management of the four studied non-native tree species, Douglas fir seems to be the best choice for cultivation in Polish forests.

Nitrogen Deposition Enhances Interactions Between Litter Types During the Early Stage of Decomposition

ABSTRACTNitrogen deposition can alter the interactions between litter types during their decomposition, and thus affect material cycling and ecosystem stability. However, it is unclear how the differences in the initial chemical properties of litter mixtures affect their response to nitrogen deposition. In this study, we investigated three litter mixtures: high quality–high quality (Robinia pseudoacacia–Stipa grandis, Rp‐Sg, mixed form F1), high quality–low quality (Rp–Setaria viridis, Rp‐Sv, F2), and low quality–low quality (Artemisia gmelinii–Sv, Ag‐Sv, F3). Each of the litter types can be found in Rp plantations in the Loess Hilly Region, China. We subjected the litter mixtures to nitrogen deposition treatments (0 and 4–12 g·m−2·a−1) in a 326‐day indoor decomposition experiment. Decomposition parameters of each litter type in monospecific and mixed decomposition were compared to investigate the interactions between litter types under nitrogen deposition. The results indicated that, in the early stage of mixed decomposition, litter types of similar substrate quality did not affect the decomposition of each other (i.e., in the F1 and F3 mixtures). In contrast, the decomposition of low‐quality litter (Sv) was accelerated by that of high‐quality litter (Rp) when there was no nitrogen deposition. The overall degree of the mutual effects (Rinter,t) for the litter decomposition rate in F1, which has an overall higher quality, increased and then decreased with increasing nitrogen deposition; whereas the Rinter,t for the litter decomposition rate in F2 and F3, which have an overall poor quality (p &lt; 0.05), increased continuously. In general, nitrogen deposition increased the interactions between litter types during the early stage of mixed decomposition. Given that most interactions were synergistic, this effect of nitrogen deposition may alleviate its inhibitory effects on litter decomposition in the study region.

The effects of some chemical compounds on the sound absorbing ability of tree bark.

Tree bark is an important natural polymer for sound absorption. The main components in the bark of different tree species are polymers with high molecular weight such as cellulose, hemicellulose, and lignin. The aim of this study is to determine the noise reduction coefficient (NRC), lignin, alcohol-benzene solubility (ABS), carbon (C), and nitrogen (N) contents in samples taken from the bark of different tree species-black locust (Robinia pseudoacacia), narrow-leaved ash (Fraxinus angustifolia), stone pine (Pinus pinea), silver lime (Tilia tomentosa), sweet chestnut (Castanea sativa), sessile oak (Quercus petraea), and maritime pine (Pinus pinaster) and to investigate the relationship between these chemical properties and sound absorption measurements. Tree species showed a statistically significant difference in terms of all measured variables. In the correlation matrix obtained as a result of the analysis, only ABS showed a significant and the highest positive correlation with the NRC, with a correlation coefficient of r = 0.812. ABS in bark is seen as the most important chemical factor regarding sound retention, indicating the abundance of extractives in barks of different tree species. An investigation into the relationship between sound retention and different extractive substance and contents of different extractive substances in bark is recommended for further studies.

Determination of the Critical Voltage for the Observation of Uncoated Wood Samples in Electron Microscopy.

Electron microscopy (EM) is a key tool for studying the microstructure of wood; however, observing uncoated samples poses a challenge due to surface charging. This study aims to identify the critical voltage that allows for the effective observation of uncoated wood samples without significant loading. As part of the experiment, samples of different wood species were tested, including Acacia (Robinia pseudoacacia L.), Oak (Quercus robur L.), Maple (Acer pseudoplatanus spp.), Ash (Fraxinus excelsior L.), Spruce (Picea abies (L.) Karst.), Thermowood (Thermal modifed Spruce), Garapa (Apuleia leiocarpa), Ipé (Handroanthus spp.), Merbau (Intsia bijuga), and Massaranduba (Manilkara spp.). Several methods were tested for surface preparation for SEM analysis, including the use of a circular saw, a hand milling machine, and a microtome. The results show that the optimal voltage for observing uncoated wood samples varied depending on the wood species. Regarding the selection of wood species and the results obtained, it was found that uncoated samples could be effectively observed. This finding suggests that practical observations can be accelerated and more cost-effective, as all wood species exhibited the required voltage range of 1 kV to 1.6 kV. Additionally, it was determined that using a secondary electron detector was optimal for such observations, as it provided a sufficiently strong signal even at relatively low voltages. Conversely, when using a backscattered electron detector, it was more beneficial to use coated samples to achieve a sufficient signal at higher voltages. This study brings new knowledge that will facilitate further research and applications of electron microscopy in the study of other wood species or wood-based materials.

THE FIRST RECORD OF ABLEPHARUS KITAIBELII (BIBRON AND BORY DE SAINT-VINCENT, 1833) IN THE NORTH OF OLT COUNTY

The lizards of the fam. Scincidae are represented by a single species over most of South East Europe. The Snake-eyed Skink is one of the smallest lizards in Europe with a relatively secretive lifestyle. Regarding the distribution of this species, the Snake-eyed Skink - Ablepharus kitaibelii (Bibron &amp; Bory de Saint-Vincent, 1833) has not been reported so far in the north of Olt County. It is the first recording in this area. This research indicates for the first time two populations of Ablepharus kitaibelii situated in the commune of Bărăști, in an area where the species was not previously documented. This commune is located in the north of Olt county, 50 km away from the municipality of Slatina, county residence. Bărăști commune is situated in the hilly region with an altitude of up to 318 m, part of the territory between the Cotmeana and Vedea rivers, known as the Cotmeana Platform, on the line Drăgășani-Spineni-Mârghia-Pitești, which makes the transition between hill and plain. The Snake-eyed Skink is considered threatened in Romania. This rare species with a restricted and fragmented distribution is present in Annex IV of the Habitats Directive, the local protection of this species being necessary through special conservation measures, such as: stopping deforestation, stopping the expansion of agricultural or residential areas in the researched area, controlling intensive grazing (there being several sheep and goat pens in the area), replacement of False Acacia and Pine plantations with Oak, supervision of stray cats and dogs, etc.

The impact of ungulate browsing on black locust competitive abilities in a temperate oak forest

Invasive species such as black locust (Robinia pseudoacacia) cause several problems in conserving semi-natural forests in Europe. The selective browsing of ungulates can be a prominent regulating factor in the spread of black locusts. We set out a 4 year-long experiment in a fenced area of a Turkey oak (Quercus cerris) – sessile oak (Quercus petraea) forest in Hungary to 1) evaluate short-term responses of black locust saplings to simulated browsing; 2) identify the effects of browsing and soil conditions on the competition between black locust and oak saplings. We hypothesized that clipping treatments would reduce the growth and vitality of black locusts and indirectly enhance oak sapling development. Vegetation patches were designated to separate oak saplings with treated and intact black locust saplings, and without black locust. After the first round of treatments in September 2014, clipped black locusts compensated for height and shoot loss. The summer drought in 2015 reduced the survival of black locusts independently of the clipping and many saplings disappeared from previously occupied plots. In addition, the effects of the second clipping treatment in September 2015 have significantly slowed down, even hindering further growth of the clipped saplings. Soil nitrogen level was not higher in black locust plots, but low pH and significant soil compaction could be limiting factors for all saplings. Our results did not confirm any significant inhibitory effect of black locust on oak sapling development, but sessile oak had increased height growth compared to Turkey oak in black locust plots. It seems that browsing is only a secondary factor that influences the growth and competitiveness of black locusts since only repeated browsing after a heavy drought period could prevent black locust saplings from compensating for their losses.

Perception of local stakeholder groups about certain invasive alien bee pasture species around Lake Kolon

The apiculture sector in Hungary is currently heavily dependent on invasive alien bee pasture species such as the black locust (Robinia pseudoacacia L.), the common milkweed (Asclepias syriaca L.) and the invasive goldenrod species (Solidago gigantea Ait. and Solidago canadensis L.). Between March and October 2023, semi-structured interviews were conducted around Lake Kolon with representatives of the main stakeholder groups: nature conservationists, beekeepers, foresters and farmers. The main aim of our investigation was to assess the perception of the four stakeholder groups about the invasive alien bee pasture species and reveal the conflicting points. Based on our results the presence of black locusts in the area is only undesirable for the conservation sector, the common milkweed is the most damaging species from both a conservational and agricultural point of view. The invasive goldenrod species are less common but are also unfavourable from a conservation point of you. They play a role in preparing bees for winter Beekeepers mentioned other valuable bee pastures (e.g. protective forest strips, flowering trees and shrubs, wildflower meadows, and native bee pastures such as linden) and some of them could replace the invasive alien species. Agricultural subsidies are essential for local farmers. However, they are reluctant to take advantage of subsidies specifically targeted at indigenous bee pasture species, because for some reason they are not seen as favourable. In terms of conflicts, foresters and farmers consider the regulations and restrictions of the conservation sector too strict. Due to the rich wild bee fauna in the area, the conservationists do not prefer the presence of migratory beekeepers with their hives, which puts extreme competitive pressure on wild bees. Beekeepers have reported conflict cases with farmers about bee poisoning in oilseed rape. Overall, it can be said that the beekeepers interviewed are open to the indigenous bee pasture plant species, but currently, they are dependent on the invasive alien bee pasture species. In addition, there are conflict cases between the stakeholder groups, but most of them can be resolved through discussion.

First Report of Perenniporia fraxinea Causing Heart Rot Disease of Styphnolobium japonicum in China.

Styphnolobium japonicum (L.) Schott, is an ornamental species of Leguminosae, widely planted as a roadside tree in north regions of China (Kite et al. 2007). In mid-June of 2022, 45 ca. 30-year-old plants of S. japonicum growing along roadsides in Dalian, China were found to be infected by a polypore fungus that appeared to be killing many of these plants. The infected trees show leaf wilt early in the growing season, and in mid-summer, pale yellow fruiting bodies appeared at the base of the tree trunks. The fruiting bodies were effused-reflexed, with a pale yellow to yellow-brown pileus when dry, and gradually formed whitish pores on their undersurface. Over two years, approximately 15% of S. japonicum trees became infected in a ca. 10-ha area. Thirteen morphologically identical strains were generated from 20 samples by collecting 8 mm3 tissue pieces from 20 fruiting body stroma and growing these out on potato dextrose agar (PDA). The basidiospores from field collected fruiting bodies were abundantly produced in pores which were circular and 4-6 per mm, hemispherical and dropletshaped, hyaline, thick-walled and smooth, (5.8-6.9)×(4.8-5.7) μm. On PDA, the mycelia were initially white and sparse, later becoming fluffy in the center, white at the margins, and pale yellow on the underside. These morphological characteristics were consistent with Perenniporia spp., as described recently in Cui et al. (2019). To further confirm species identification, representative isolate DL was selected for molecular identification. The small subunit (SSU), internal transcribed spacer (ITS), and large subunit (LSU) of the ribosomal DNA (rDNA) were amplified with primers NS1/NS4, ITS1/ITS4 (White et al 1990), and LROR/LR7 (Aveskamp et al. 2010), respectively. The sequences were uploaded to GenBank as accession OQ592891 for ITS; OQ629793 for SSU; and OQ629858 for LSU. Sequence comparisons against the GenBank database showed 99% to 100% identity (GenBank accessions KX081110.1, MG847270.1, JF706344.1) with a strain of Perenniporia fraxinea (Bull.) Ryvarden [syn.: Vanderbylia fraxinea (Bull.) D.A. Reid]. Phylogenetic analysis also placed these isolates in a highly supported clade with the other isolates of Perenniporia fraxinea. To test pathogenicity, fresh hyphal plugs were inoculated onto sterile wounds artificially punctured on the stem surface of five healthy one-year-old S. japonicum seedlings, and plants were incubated at 28℃ with a 12-hour photoperiod in a humid chamber for 7 days. PDA plugs were used as controls and the pathogenicity test was repeated three times. After 7 days, lesions were observed on all inoculated stems, while the mock-inoculated stems were asymptomatic, and no fungal pathogen was isolated. The same fungus was re-isolated from the inoculated wounds to complete Koch's Postulates. The original pathogenic and the re-isolated inoculated fungus was identified as P. fraxinea. This fungus has also been found on Robinia pseudoacacia in Japan (Matsumoto et al. 2023) and in Germany (Kehr et al. 2020). However, to our knowledge, this is the first report of P. fraxinea causing heart rot of S. japonicum in China. The wide occurrence of this pathogenic fungus on stem bases of S. japonicum, and its lethal effect on host plants should be given more attention by landscape maintenance workers and extension agents.

Tree Health Survey Results of Juvenile Black Locust Clones

The black locust (Robinia pseudoacacia L.) is a significant tree species in many European countries, especially Hungary. The Hungarian Forest Research Institute initiated a project in the 1960s to improve Robinia stem quality and yield. Five newly bred clones (Laposi, Napkori, Hajdúsági, Farkasszigeti, Püspökladányi) are currently undergoing tests in three trials (Debrecen, Napkor, and Nyírbogdány). Studying the health status of these clones is vital to the cultivar certification process. In September 2022 (Napkor) and August 2023 (Nyírbogdány, Debrecen), we investigated 30 trees per clone by estimating average foliage loss per individual and observing the extent and causes of damage to the crown (canopy), branches, and trunk in each experimental plot. At the same time as the tree health survey, NDVI measurements were also performed in Debrecen using Trimble Greenseeker handheld sensor. Our results indicate that the clones possess good drought tolerance; however, the NDVI results revealed significant differences between the clones: Laposi and Farkasszigeti have the highest NDVI values (0.76 and 0.77), and Püspökladány has the lowest (0.74). Napkori is the most susceptible to fungal disease, exhibiting significant incidences of bark necrosis caused by Phomopsis petiolorum. The rate of insect damage was negligible, even with low levels of damage by leaf miners, which are very common in black locust plantations.

Optimizing Low-Efficiency Robinia pseudoacacia Forests on the Loess Plateau Based on an Evaluation of the Ecological Functions of Soil and Water Conservation

The vegetation for water and soil conservation on the Loess Plateau has resulted in the formation of large areas of low-quality and inefficient forests during its growth process, thereby hindering the high-quality development of such vegetation and compromising the sustainability of the ecological functions of soil and water conservation. This study focuses on Robinia pseudoacacia forests in the Caijiachuan watershed in the Loess region of western Shanxi. A comprehensive evaluation system for the ecological functions of soil and water conservation has been established to conduct a comprehensive assessment of the Robinia pseudoacacia forests. Additionally, the study identifies low-efficiency Robinia pseudoacacia forests and proposes reasonable regulation and control measures. The main research conclusions are as follows: (1) There are significant differences in the water and soil conservation functions among different Robinia pseudoacacia forests. The degree of inefficiency in these forests increases with forest density, and Robinia pseudoacacia forests with slopes between 35° and 40° are all low-efficiency forests. (2) The average density of high-efficiency Robinia pseudoacacia forests is 1655 trees per hectare, medium-efficiency forests average 1780 trees per hectare, and low-efficiency forests average 1927 trees per hectare. By substituting forest density, diameter at breast height (DBH), tree height, and crown width into the low-efficiency forest discrimination function, low-efficiency forests can be identified. The main influencing factors of low-efficiency forests are the Margalef richness index of shrubs, the total soil nitrogen content; and the nitrate nitrogen content. (3) Regulation measures for low-efficiency forests include controlling forest density to 1655 trees per hectare, increasing the richness of understory shrubs, and enhancing total soil nitrogen and nitrate nitrogen content by planting leguminous plants such as Lespedeza bicolor, Sophora davidii, and Vicia sepium. The research results can construct a comprehensive evaluation system for the ecological functions of Robinia pseudoacacia forests for water and soil conservation, identify low-efficiency forests, and provide precise regulation based on the causes of inefficiency, ensuring the sustainable function of Robinia pseudoacacia forests for water and soil conservation.

Micropropagation of Robinia pseudoacacia L. Genotypes, Selected for Late Flowering Characteristics

Robinia pseudoacacia L., commonly known as black locust, is a nitrogen-fixing species characterized by multiple uses. Among these uses, black locust is of special interest to beekeepers due to its abundant flowering and delicious honey. Given the great importance of honey production in Italy, beekeepers are looking for genotypes that have a delayed flowering time. As a consequence, the aim of the present study was to develop a complete protocol of micropropagation for genotypes, which have been selected in the Veneto region due to their delayed flowering, i.e., about 3 months, in comparison with the normal flowering time (from late April to early June). The subsequent steps of the micropropagation protocol (explant decontamination, shoot induction, proliferation, and rooting) were investigated and optimized. The most effective decontamination treatment of explants (axillary buds from shoots developed in a greenhouse) was obtained using 50 mg/L AgNO3 for 20 min. This method resulted in the highest survival and regeneration rates for the explants (90%), although contamination was slightly higher than when using HgCl2 and NaOCl. The best medium for shoot establishment was MS with 1 mg/L of mT, which achieved 100% regeneration of the explants. In comparison with BA, mT at 1 mg/L was shown to be the best stimulator of shoot proliferation, especially in combination with 0.7 mg/L GA3 (Proliferation Rate, 4.7). An intermediate 2 h treatment with AgNO3, in combination with mT, was shown to be beneficial in improving the shoot proliferation and quality in the subsequent subculture in a gelled medium. As for shoot rooting, the shoots that were pre-treated in NH4NO3-free and mT-free MS medium gave the highest ex vitro rooting percentage in a cell tray (80%) and the highest number of roots per shoot (3.6). This optimized protocol opens the door to the massive micropropagation of valuable genotypes of black locust selected for delayed flowering. This is an outcome of extraordinary importance for beekeepers.

Response strategies of five common warm temperate plant species to insect defoliation

AbstractUnder the background of global climate change, climate warming has led to an increase in insect herbivory, which significantly affects the growth, survival, and regeneration of forest plants in the warm temperate zone of China. Plants can adopt defense responses to adapt to insect defoliation. Therefore, field experiments were conducted on five common warm temperate species, Quercus acutissima, Quercus serrata, Quercus aliena, Quercus dentata, and Robinia pseudoacacia. We measured the leaf traits of healthy trees and insect defoliated trees, to explore the response strategies of common species in warm temperate zones to insect defoliation. Our results showed that native species stored more carbon in extreme environments for survival rather than growth, while the alien species R. pseudoacacia tended to adopt active resource acquisition strategies and were more inclined towards growth. The content of tannins and flavonoids in the alien species R. pseudoacacia did not significantly increase after leaf damage, while the content of secondary metabolites such as tannins, flavonoids, and total phenols in the native species Q. acutissima, Q. serrata, Q. aliena, Q. dentata increased significantly after leaf damage. This indicated that compared to alien species, native species invested more resources in defense, which might reduce resource allocation for growth. Thus, the native Quercus species have stronger resistance than the alien species R. pseudoacacia after insect defoliation.

Modelling of forest carbon dynamics in different forest management scenarios: A case study on poplar and black locust plantations in Hungary

Abstract Long-term forest carbon modelling is helpful in climate change mitigation actions. Estimating potential carbon sequestration in forests can be considered the long-term strategy for low carbon and climate resilience in the National Determination Contribution. In Hungary, the black locust (Robinia pseudoacacia) and poplars (Populus sp.) are prominent and dominant species in reforestation and afforestation projects. The research aimed to estimate the carbon dynamics of black locust and white poplar long rotation plantations in some forest management scenarios. Thirty-six forest management scenarios were developed from two species, six yield classes, and tree wood utilization. CO2FIX modelling projected carbon dynamics for 45 years of rotation. Our findings have shown that class yield I resulted in the highest carbon stock compared to class yields II–VI. Black locust plantations have stored carbon to a larger extent than white poplar plantations. In terms of wood utilization, harvested black locust or white poplar wood contributed the most extensive carbon stock if used for pulp. In conclusion, from 36 forest management scenarios, the best scenario was black locust plantation in class yield I and the aim for pulp that stored the carbon at the end of rotation was 101.75 Mg C/ha. In all forest management scenarios, the soil carbon stock was higher than carbon in biomass, products, and bioenergy. Thus, conserving the soil as the dominant carbon pool is vital for future policy recommendations.

Thinning and final cutting control in black locust (Robinia pseudoacacia L.) stands: a methodological approach – Short communication

Planning, implementing and inspecting forestry operations require more extent application of certain assessment methods. These methods may need to be improved and, in some cases, their simplification is necessary in order to ease their usage in practice. Knowledge and application of auxiliary tables and functions, data on volume and methods to estimate yields are needed for the planning of any kind of forestry operations, depending on the level of planning. The main purpose of this paper is to propose relatively rapid and simple methods to estimate the volume at thinning and final cutting, and the gross above ground volume at the harvest of black locust (Robinia pseudoacacia L.) stands, as well as to introduce tending operation models tailored for black locust. All these measures could be beneficial to forest authorities and foresters who are responsible for planning and production.

Exploring the Plant Growth-Promotion Properties of Rhizospheric and Endophytic Bacteria Associated with Robinia pseudoacacia L. in Serpentine Soil.

Serpentine soils are characterized as a unique environment with low nutrient availability and high heavy metal concentrations, often hostile to many plant species. Even though these unfavorable conditions hinder the growth of various plants, particular vegetation with different adaptive mechanisms thrives undisturbed. One of the main contributors to serpentine adaptation represents serpentine bacteria with plant growth-promoting properties that assemble delicate interactions with serpentine plants. Robinia pseudoacacia L. is an invasive but adaptive species with phytoremediation potential and demonstrates extraordinary success in this environment. To explore more in-depth the role of plant growth-promoting serpentine bacteria, we isolated them and tested their various plant growth-promoting traits both from the rhizosphere and roots of R. pseudoacacia. Based on the demonstrated plant growth-promoting traits such as siderophore production, phosphate solubilization, nitrogen fixation, indole-3-acetic acid production, and ACC deaminase production, we sequenced overall 25 isolates, 14 from the rhizosphere and 11 from the roots. Although more efficient in exhibiting plant growthpromoting traits, rhizospheric bacteria showed a low rate of diversity in comparison to endophytic bacteria. The majority of the isolates from the rhizosphere belong to Pseudomonas, while isolates from the roots exhibited higher diversity with genera Pseudomonas, Bacillus, Staphylococcus, Lysinibacillus and Brevibacterium/Peribacillus/Bacillus. The capacity of the described bacteria to produce siderophores, solubilize phosphate, and fix nitrogen highlights their central role in enhancing nutrient availability and facilitating R. pseudoacacia adaptation to serpentine soils. The findings highlight the potential significance of serpentine bacteria, particularly Pseudomonas, in contributing to the resilience and growth of R. pseudoacacia in serpentine environments.

Climate and soil explain contrasting intraspecific trait variability of widespread species over a large environmental gradient

Both climatic and edaphic conditions are currently undergoing significant changes on a global scale. Early studies have suggested that climate and soil together shape plant performance. However, establishing a precise theoretical framework to describe trait-environment relationships has proven challenging. Understanding and identifying the patterns and drivers of intraspecific trait variation is crucial for anticipating changes in plant distributions. This study aimed to examine the relative importance of various environmental drivers in explaining intraspecific trait variation for two widespread species, Sophora japonica and Robinia pseudoacacia, across a broad environmental scale spanning from the southeast to the northwest of China. Intraspecific variation in fourteen functional traits accounted for 23.4 % of S. japonica and 28.4 % of R. pseudoacacia, indicating that these species exhibit a degree of plasticity in response to changing environmental conditions. There were differences in the influence of climatic and edaphic factors on intraspecific trait variation. For both species, hydraulic trait variations were primarily driven by climate during the growth season and climatic seasonality. In comparison, soil chemical properties accounted for a substantial proportion of the variability in leaf economic traits. Our results show that S. japonica and R. pseudoacacia responded differently to variations in climatic factors. In contrast, the impact of soil factors on traits was more consistently observed between these two species. We conclude that soil conditions, like climate, are crucial factors in investigating geographic variation in functional traits and species distributions. Our analysis also highlights that species specificity must be considered when discussing plant adaptability to climate change. These findings provide valuable insights into how and to what extent climatic and edaphic factors influence species distributions by driving the intraspecific trait variability.

Ecological Functions of Autumn Olives for Improving Vegetation Species Diversity and Habitat Conditions Supporting Their Growth: A Study of Tedorigawa River, Japan

ABSTRACTThus far, no studies have quantitatively investigated the ecological functions of wood communities for increasing vegetation species diversity and promoting supportive habitat conditions for their growth. To fill this gap, this study investigates the ecological function of the autumn olive (Elaeagnus umbellata var. umbellata) community, a typical native wood community of Japan. We selected the Tedorigawa River, a representative rapid river of Japan, as a case‐study subject and conducted field surveys to investigate the relationships between the autumn olive, black locust, and oriental wormwood‐kawarahako communities (among six total vegetation communities) and their respective species compositions. Hydraulic simulations helped investigate significant differences in the cover ratio of native species that grow in rivers and alien species and, differences in the physical and environmental characteristics among the three typical vegetation communities in the river channel (native grass community, native wood community, and alien wood community). The results showed that autumn olives support the growth of native species that prefer wet conditions and control alien species' growth. This ecological function is supported by the characteristic hierarchical structure of autumn olives, including low‐density trunks and leaves and low height, which create bright light conditions in the community. The autumn olive community was also found to obstruct flood flow, which enhances the deposition of fine sediments and nutrients. These characteristics enhance wet conditions to support the growth of native species that prefer these conditions.