Fraxinus Velutina Research Articles

Eco-physiological adaptability in mixtures of Robinia pseudoacacia and Fraxinus velutina and coastal eco-engineering

Mixed-species plantations have potential advantages than monocultures. In this paper, the eco-physiological adaptability of single seedlings of nitrogen (N)-fixing Robinia pseudoacacia and non-N-fixing Fraxinus velutina were compared with mixed-species with the proportion of 1:1 under salt stress by pot experiments. The results showed that relative growth rate (RGR) and the maximum net photosynthetic rate decreased with the increase of soil salinity, while relative conductivity of leaves increased. R. pseudoacacia and F. velutina showed higher RGR in mixtures than in their monocultures, respectively. The relative conductivity of R. pseudoacacia in mixtures was similar to in monocultures while it was lower for F. velutina in mixtures than in monocultures. The activities of urease and phosphatase, hydrolysis nitrogen and available phosphorus in rhizosphere were affected significantly in salinity treatments, but total nitrogen and phosphorus did not. Compared to monocultures, F. velutina in mixtures increased urease activity and hydrolysis nitrogen in rhizosphere soil, and R. pseudoacacia increased phosphatase activity, available phosphorus and total phosphorus in rhizosphere soil. Therefore, there was a reciprocal benefit on the use of N and P in rhizosphere soil between them in mixtures, which was an important mechanism for more productivity in the mixture of R. pseudoacacia and F. velutina and an efficient method for coastal eco-engineering on large scale.

天津滨海绿地的植物种类及其应用研究

天津滨海区域长期受海水浸渍拥有大量的盐碱荒地，植物生长受到严重影响，植被生态恢复尤为重要。因此，研究天津滨海绿地中已有应用的植物种类和植物生长势情况，对选择适用于天津滨海区域生态修复的植物种类具有重要意义。对天津滨海绿地应用的园林植物和自发生长的植物种类进行调研，重点分析植物种类及其生长势、出现的频度和多度，并计算重要值，旨为天津滨海区域的植被选择和恢复提供参考和借鉴。结果表明：天津滨海绿地有园林植物及自生植物共45科102属128种(含品种)，其中白皮松、油松、合欢等7种生长势较差。乔木应用较多的为国槐、紫叶桃、西府海棠、绒毛白蜡、紫叶李等；灌木应用较多的为大叶黄杨、金叶女贞、木槿、紫穗槐、火炬树等；草本植物应用较多的为芦苇、高羊茅、紫苜蓿、独行菜、马蔺等。 Tianjin coastal area is seawater impregnated, seriously affecting plant growth and have a lot of salt and alkali wasteland, vegetation ecological restoration is particularly important. Therefore, it is important to study the plant species, plant growth potential and application status of Tianjin coastal green land, and to select the plant species suitable for ecological restoration in Tianjin coastal area. The research on plant species and spontaneous growth plants of Tianjin coastal green space was carried out. The plant species and their growth potential, frequency and degree of occurrence were analyzed, and the important values were calculated, to provide reference for vegetation selection and restoration in Tianjin coastal area. The results showed that there were 129 species (including cultivation), belonging to 45 families and 102 genera. Among them, seven kinds of growth potentials such as: Pinus bungeana, Pinus tabulaeformis and Albizia julibrissin were poor. Trees such as Sophora japonica, Amygdalus persica, Malusmicromalus, Fraxinus velutina, Prunus cerasifera, etc. were more widely used; Shrubs such as Euonymus japonicas, Ligustrum vicaryi, Hibiscus syriacus, Amorpha fruticosa, Rhustyphina, etc. were more widely used; Herbs such as Phragmites australis, Festucaelata, Medicago sativa, Lepidium apetalum, Irislactea etc. were more widely used.

Influence of Different Soil Moisture Content on Plant Configuration for the Submerged Area of Shifosi Reservoir, China

To propose a reasonable configuration of plant measures and specific planning to improve the soil quality and the surrounding ecological environment of submerged area in Shifosi reservoir, we analyzed the soil moisture content and other key physical properties such as bulk density, maximum water-holding capacity, capillary water-holding capacity, field capacity and porosity of the submerged area. Soil samples were collected within 500 m scope from the auxiliary dam and tested using test methods in compliance with the national standard LY/T1215-1999. The correlation analysis showed that a highly significant correlation existed between the moisture content with other physical properties. The capillary water-holding capacity had the highest correlation with the soil water content, followed by the maximum waterholding capacity, porosity, field capacity, and bulk density. As the changes in soil moisture content may affect the variation of other physical properties, the immersion area was divided into three regions according to their soil water contents. In region 1, the moisture content was between 23.08% and 32.96%; in region 2, the moisture content was between 21.18% and 23.08%; and in region 3, the moisture content was below 19.85%. In each region, the adaptive plant measures and configurations were put forward on the basis of natural, social and economic conditions, as well as vegetation status. In region 1, the selected tree was Salix matsudana, shrub was Forsythia mandshurica, and suitable herb was Iris lactea var. chinensis. In region 2, the proper tree was Fraxinus velutina, shrub was Amorpha fruticosa, and herb was Festuca arundinacea. In region 3, the suitable tree was Pinus tabulaeformis var. mukdensis, shrub was Lespedeza bicolor, and herb was Eleocharis yokoscensis. The rational allocation of vegetation may prevent soil erosion, contribute to the full use of the land of the submerged area, achieve optimization of social, economic, and ecological benefits, and provide a reference for plant configuration of other reservoirs in Liaoning Province, China.

A R2R3 MYB transcription factor from ash positively regulates salt response in tobacco

The roles of MYB transcription factors are diverse and important in regulating environmental stress in plants. In this study, the R2R3 MYB gene FvMYB2 (GenBank Accession No. KY767843) and its promoter region were cloned from ash (Fraxinus velutina Torr.). Phylogenetic analysis revealed that FvMYB2 was clustered with VvMYB60 from Vitis vinifera. PlantCARE software analysis showed that its promoter contained different cis elements involved in diverse abiotic stresses. The expression patterns of FvMYB2 were investigated under different abiotic stress conditions. FvMYB2 subcellular localization was mainly localized in the nucleus. Overexpression of FvMYB2 in tobacco showed enhanced salt resistance and upregulation of stress- and ABA-related genes after NaCl treatment. These results indicated that FvMYB2 may play a positive role in salt stress regulation mediated by ABA-dependent signaling mechanisms.

De novo transcriptome analysis of Fraxinus velutina using Illumina platform and development of EST-SSR markers

To facilitate functional genomic analysis and molecular breeding of velvet ash (Fraxinus velutina Torr), the de novo sequencing was carried out by Illumina sequencing technology. The cDNA samples were prepared from eleven different tissues of velvet ash and sequenced by using the Illumina genome analyzer. Subsequently, de novo assemebly, functional annotation databases, and the screening of expressed sequence tag-simple sequence repeats (EST-SSRs) were performed by comparing with corresponding databases using BLASTx and software tools. We obtained 51 698 unigenes with an average length of 661 bp and an N50 length of 980 bp. Among all these unigenes, 41 267 (79.8 %) were annotated in the NCBI non-redundant protein database and 25 236 (48.8 %) were annotated in the Swiss-Prot database. A total of 31 546 (61.0 %) and 13 281 (25.7 %) unigenes were successfully categorized to 59 and 25 functional groups, respectively, by gene ontology categories and clusters of orthologous group categories. A total of 22 323 (43.2 %) unigenes were assigned to 128 pathways using the Kyoto encyclopedia of genes and genomes pathway database. Additionally, 3 249 EST-SSRs markers were detected in 51 698 unigenes from velvet ash. Based on 3 249 EST-SSRs markers, 1 800 primer pairs were successfully designed using Primer 3. In the 50 randomly selected primers, 48 successfully amplified fragments, and 42 showed polymorphisms. We completed a successful application of the Illumina platform to de novo transcriptome assembly of velvet ash, which has the potential to be used for discovering novel genes and further characterization of gene expression profiles.

Overexpression of an MYB-Related Gene FvMYB1 from Fraxinus velutina Increases Tolerance to Salt Stress in Transgenic Tobacco

MYB transcription factors (TFs) in plants play important roles in abiotic stress tolerance. Here, we report that an MYB-related TF gene, named FvMYB1, was isolated from the salt-tolerant tree species Fraxinus velutina Torr. The real-time PCR analysis showed that the FvMYB1 transcript increased remarkably in response to salt treatment. Subsequently, the FvMYB1 gene was transferred into the tobacco genome via the Agrobacterium-mediated approach. PCR and Southern blot verified that the FvMYB1 gene had been expressed in transgenic tobacco. The overexpressing transgenic seedlings displayed better salt tolerance in root length, shoot fresh weight, and shoot/root ratio compared to the wild type. Moreover, along with the superoxide dismutase and peroxidase activities and proline content that were significantly increased in the transgenic plants, the transcriptions of a series of stress-responsive genes were up-regulated under salt treatment. Further, an analysis of the upstream sequence of the FvMYB1 gene revealed that the promoter could enhance GUS gene expression in transgenic tobacco with NaCl treatment. These results indicate that FvMYB1 functions as a transcriptional activator that plays a regulatory role in salt stress tolerance of F. velutina.

Phytochemical Investigation of Hydroalcoholic Extractives from Branches of Fraxinus velutina

Phytochemical Investigation of Hydroalcoholic Extractives from Branches of Fraxinus velutina

Purification and Spectroscopic Elucidation of a New Coumarin Glucoside in Fraxinus velutina Heartwood

A new natural compound, esculetin-5-O-β-D-glucopyranoside (1), along with two known flavonoids, quercetin (2) and kaempferol-3-β-D-glucopyranoside (3), was purified from the heartwood of Fraxinus velutina. Their chemical structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR, and MS techniques.

Salt tolerance and alterations in cytosine methylation in the interspecific hybrids of Fraxinus velutina and Fraxinus mandshurica

For cross-pollination trees, the optimal breeding method is hybridization. Tree heterosis is commonly present and is the main research focus in tree crossbreeding. Salt stress and interspecific hybridization may lead to DNA methylation changes. The study crossed Fraxinus mandshurica (female parent) with Fraxinus velutina (male parent) to obtain interspecific F1 hybrid progenies that could obtain the good characters of parents. The results showed that growth and survival rate of the interspecific hybrid progenies (F1 hybrids of F. mandshurica × F. velutina) were significantly higher than those of intraspecific open pollinated plants from parental F. mandshurica and F. velutina. Salt tolerance and cytosine methylation in interspecific F1 hybrids and the intraspecific open pollinated plants from parents were examined. Membrane permeability, ROS and antioxidant activity, malondialdehyde, and photosynthesis were measured after salt treatment and genomic methylation was analyzed using a methylation-sensitive amplified polymorphism protocol. F1 hybrids exhibited heterosis for growth in normal as well as high salt conditions. DNA methylation in the F1 hybrids was lower than the intraspecific open pollinated plants from parents. Salt treatments changed DNA methylation patterns in F1 hybrids. Genomic DNA of the intraspecific open pollinated plants from parents had internal cytosine methylation (average of 13.22 %), whereas F1 hybrid seedlings had external cytosine methylation (average of 7.34 %). Such changes in DNA methylation patterns in F1 hybrids suggest a connection between salt tolerance and epigenetic mechanisms in plants. We observed that alteration of DNA methylation was closely correlated with the adaptation to the salt stress and provided epigenetic mechanisms of salt tolerance in the interspecific hybridization of trees.

Effects of wildfire on riparian trees in southeastern Arizona

We measured fire damage to 250 riparian trees in 2003–2004, and again in 2012–2013, in a southeastern Arizona grassland burned by wildfires in 2002, 2009, or both. Following a single fire, combined mortality or survival only by ground-level resprout was 64% for desert willow (Chilopsis linearis), 57% for Fremont cottonwood (Populus fremontii), 48% for Arizona walnut (Juglans major), 32% for velvet ash (Fraxinus velutina), and 25% for Wright's sycamore (Platanus wrightii). A second fire burned 120 of the trees that happened to have been less damaged by the first fire. Distinctions among species in overall fire damage persisted after the second fire but to a lesser degree. By the conclusion of our study, 26% of the 250 trees had died completely while another 32% survived only as relatively small resprouts. We conclude that the fires substantially reduced both the abundance and crown volume of mature riparian trees in the study area.

Fine root distribution, characteristics and rhizosphere soil properties in a mixed stand of Robinia pseudoacacia and Fraxinus velutina in a saline soil

The spatial distribution and characteristics of fine roots (< 2 mm in diameter), and rhizosphere soil properties were studied in a mixed planted forest of black locust (Robinia pseudoacacia L.) and velvet ash (Fraxinus velutina Torr.) 27 years after planting in a coastal saline soil of the Yellow River delta, China. The results of fine root analysis showed that the fine roots of both black locust and velvet ash were mainly distributed in the soil layer at 0–20 cm depth and 50–150 cm from trees. The fine root distribution of both species suggests a strategy of avoiding salinity rather than salt –tolerance. The horizontal spread distance of fine roots of velvet ash was evidently longer than that of black locust. The fine root biomass, specific root length, specific root area, specific root volume and root activity were significantly higher for velvet ash in comparison with black locust. The results of soil analysis showed that rhizosphere soil pH of black locust and velvet ash were significantly lower compared with non-rhizosphere soil. The available N content in rhizosphere soil of black locust was higher than that of velvet ash. However, the contents of soluble salt, organic matter, available P and available K in rhizosphere soil of velvet ash were higher than those of black locust. The above results indicated that the differences between black locust and velvet ash in fine root distribution, characteristics and rhizosphere soil properties were the major reasons for that velvet ash showed stronger acclimation responses than black locust to the coastal saline soil.

Molecular cloning and expression analysis of FvMYB1 from Fraxinus velutina Torr.

Molecular cloning and expression analysis of FvMYB1 from Fraxinus velutina Torr.

Effects of learning experience on behaviour of the generalist parasitoid Sclerodermus pupariae to novel hosts

AbstractMassicus raddei Blessig (Coleoptera: Cerambycidae), also referred to as the oak long‐horned beetle (OLB), is a non‐natural host for the generalist parasitoid Sclerodermus pupariae Yang et Yao (Hymenoptera: Bethylidae). To determine whether this generalist parasitoid might be a suitable agent for the control of OLB, the adaptive learning experience of adult female parasitoids to OLB larvae was investigated in the laboratory. A Y‐tube olfactometer bioassay was used to examine the effects of adaptive learning experience on the foraging ability of parasitoids for OLB larvae. The results indicated that parasitoids were significantly attracted by the volatiles of ash bark, Fraxinus velutina, with emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) larvae and larval frass, after exposure to ash bark mixed with EAB larval frass (learning condition A). In contrast, after exposure to oak bark, Quercus liaotungensis, mixed with OLB larval frass (learning condition C), parasitoids showed significant preference for the volatiles of oak bark with OLB larvae and larval frass. On the basis of the results of no‐choice tests, we found that parasitoids exposed to learning condition C had greater paralysis efficiency and higher OLB larvae parasitism rates than those exposed to learning condition A or no experience. Furthermore, parasitoids fed on OLB larvae in learning condition C had significantly greater paralysis efficiency and higher OLB larvae parasitism rates than other parasitoids tested. Parasitoids fed on EAB larvae in learning condition A had the lowest paralysis efficiency and OLB larvae parasitism rates among the parasitoids tested. These findings suggested that adaptive learning significantly enhanced the ability of a generalist parasitoid to utilize a novel host. This may provide a new approach to controlling non‐natural hosts using generalist parasitoids.

A New Species of Sclerodermus (Hymenoptera: Bethylidae) Parasitizing Agrilus planipennis (Coleoptera: Buprestidae) from China, with a Key to Chinese Species in the Genus

Abstract A new parasitoid reared from Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), Sclerodermas pupariae n. sp. (Hymenoptera: Bethylidae), is described from China. S. pupariae was reared from A. planipennis in China attacking velvet ash (Fraxinus velutina Torr. ), a tree native to North America. Life-history studies of S. pupariae in the field and laboratory indicated it is a gregarious idiobiont ectoparasitoid of pupa and larva of A. phnipennis and has up to five generations per year. Parasitism rate in the field was 13%. Adult wasps reared from single host pupa or mature larva ranged from 24 to 56 individuals. Based on laboratory rearing, the emerging adult female to male ratio was 22:1. The new parasitoid species has a high potential as a biocontrol agent for emerald ash borer. Diagnosis of the new species with comparisons to Sclerodermas harmandi (Buysson) and a key to Sclerodermas known in China are provided.

The Biology and Ecology of the Emerald Ash Borer,Agrilus planipennis, in China

The biology, ecology, and life cycle of the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), were studied using regular inspection in the forest and observations in the laboratory. Results indicated that A. planipennis are mostly univoltine in Tianjin, China. They overwintered individually as mature larvae in shallow chambers excavated in the outer sapwood. In late July, some full-grown larvae began to build overwintering chambers, and all larvae entered the sapwood for dormancy by early November. A. planipennis pupated in the overwintering chamber from early April to mid May the following year, and the average pupal duration was about 20 days. In late April, some newly eclosed adults could be found in the pupal cells, but they had not yet emerged from the tree. Adults began to emerge in early May, with peak flight occurring in mid May. The average longevity of adults was about 21 days and the adult stage lasted through early July. The adults fed on ash foliage as a source of nutrition. Mating was usually conducted and completed on the leaf or trunk surfaces of ash trees. Oviposition began in mid May and eggs hatched on average in 15.7 days. The first instar larvae appeared in early June. The larval stage lasted about 300 days to complete an entire generation. The emerald ash borer had four larval instars on velvet ash, Fraxinus velutina (Scrophulariales: Oleaceae). The major natural control factors of A. planipennis were also investigated, and preliminary suggestions for its integrated management are proposed.

The impacts of reactive terpene emissions from plants on air quality in Las Vegas, Nevada

A three-part study was conducted to quantify the impact of landscaped vegetation on air quality in a rapidly expanding urban area in the arid southeastern United States. The study combines in situ, plant-level measurements, a spatial emissions inventory, and a photochemical box model. Maximum plant-level basal emission rates were moderate: 18.1 μgC gdw −1 h −1 ( Washingtonia spp., palms) for isoprene and 9.56 μgC gdw −1 h −1 ( Fraxinus velutina, Arizona ash) for monoterpenes. Sesquiterpene emission rates were low for plant species selected in this study, with no measurement exceeding 0.1 μgC gdw −1 h −1. The high ambient temperatures combined with moderate plant-level emission factors resulted in landscape emission factors that were low (250–640 μgC m −2 h −1) compared to more mesic environments (e.g., the southeastern United States). The Regional Atmospheric Chemistry Mechanism (RACM) was modified to include a new reaction pathway for ocimene. Using measured concentrations of anthropogenic hydrocarbons and other reactive air pollutants (NO x , ozone), the box model employing the RACM mechanism revealed that these modest emissions could have a significant impact on air quality. For a suburban location that was downwind of the urban core (high NO x ; low anthropogenic hydrocarbons), biogenic terpenes increased time-dependent ozone production rates by a factor of 50. Our study demonstrates that low-biomass density landscapes emit sufficient biogenic terpenes to have a significant impact on regional air quality.

Host specificity of Spathius agrili Yang (Hymenoptera: Braconidae), an important parasitoid of the emerald ash borer

To investigate the host range of Spathius agrili Yang (Hymenoptera: Braconidae), a total of 18 wood boring insects either in the genus Agrilus or associated with ash forests were collected, reared, and presented to S. agrili females in no-choice tests. Results showed that S. agrili can parasitize some other insect larvae in genus of Agrilus, but attack rates were significantly lower than its natural host, emerald ash borer, Agrilus planipennisi Faimaire (Coleoptera: Buprestidae). In Y-tube olfactometer tests, female S. agrili were only attracted to twigs and leaves of EAB infested Fraxinus velutina and F. pennsylvanica, and not to 12 other potential host plants. Two other plants, Prunus persica (L.) and Ailanthus altissima (Mill.), significantly repelled the EAB. Field surveys of 17 wood boring insects, including six species of Agrilus, revealed that none of these species were parasitized by S. agrili. It was indicated that the EAB natural parasitoid S. agrili has high host specificity.

Biology and damage traits of emerald ash borer (Agrilus planipennis Fairmaire) in China

AbstractEmerald ash borer (Agrilus planipennis Fairmaire) (Coleoptera: Buprestidae) is a major stem borer of ash (Fraxinus spp.). It is univoltine in Tianjin, while it is semivoltine in Heilongjiang Province, and both univoltine and semivoltine in Changchun, Jilin Province, where the majority is univoltine. The longevity of emerald ash borer adults is 17.2 ± 4.6 days (n= 45), eggs 9.0 ± 1.1 days (n= 103), univoltine larvae 308 days, semivoltine larvae 673 days, and pupae 61.2±1.6 days (n= 45). It takes about 100 days from the time larvae bore into the phloem to when they complete the pupal cell. In a 10‐year‐old velvet ash (Fraxinus velutina Torr.) plantation in Tianjin, emerald ash borer preferred to oviposit on the regions of boles from 50‐150 cm above ground, accounting for 76.7% of the total girdling. Girdling on the south side of the tree boles accounted for 43.40% of the total girdling. The emerald ash borer population density is higher at the edge of the plantation compared with the center.

Litter quality, stream characteristics and litter diversity influence decomposition rates and macroinvertebrates

Summary1. We examined the relative importance of litter quality and stream characteristics in determining decomposition rate and the macroinvertebrate assemblage living on autumn‐shed leaves.2. We compared the decomposition rates of five native riparian tree species (Populus fremontii, Alnus oblongifolia, Platanus wrightii, Fraxinus velutina and Quercus gambelii) across three south‐western streams in the Verde River catchment (Arizona, U.S.A.). We also compared the decomposition of three‐ and five‐species mixtures to that of single species to test whether plant species diversity affects rate.3. Decomposition rate was affected by both litter quality and stream. However, litter quality accounted for most of the variation in decomposition rates. The relative importance of litter quality decreased through time, explaining 97% of the variation in the first week but only 45% by week 8. We also found that leaf mixtures decomposed more quickly than expected, when all the species included were highly labile or when the stream environment led to relatively fast decomposition.4. In contrast to decomposition rate, differences in the invertebrate assemblage were more pronounced across streams than across leaf litter species within a stream. We also found significant differences between the invertebrate assemblage colonising leaf mixtures compared with that colonising pure species litter, indicating non‐additive properties of litter diversity on stream invertebrates.5. This study shows that leaf litter diversity has the capacity to affect in‐stream decomposition rates and stream invertebrates, but that these effects depend on both litter quality and stream characteristics.

First Recorded Parasitoid from China of &lt;I&gt;Agrilus planipennis&lt;/I&gt;: A New Species of &lt;I&gt;Spathius&lt;/I&gt; (Hymenoptera: Braconidae: Doryctinae)

Abstract The first reported parasitoid reared from Agrilus planipennis Fairmaire, Spathius agrili n. sp., is described from China. S. agrili was reared from A. planipennis in China attacking a Fraxinus species native to North America, Fraxinus velutina Torr., and one endemic to the region, Fraxinus mandshurica Rupr. Life history observations of S. agrili in the field and laboratory indicate it is a gregarious idiobiont ectoparasitoid and has up to four generations per year. Parasitism rates in the field ranged from 30 to 90%, with one to 35 S. agrili eggs associated with a single host. From a host larva 1–18 adult wasps (average of 8.4) were reared. Based on laboratory rearings, the emerging adult female to male ratio is 3:1.