Syringa Oblata Research Articles

Syringa oblata Lindl. Aqueous Extract Is a Potential Biofilm Inhibitor in S. suis.

Streptococcus suis (S. suis) is a zoonotic pathogen that causes severe disease symptoms in pigs and humans. Syringa oblata Lindl. distributed in the middle latitudes of Eurasia and North America were proved as the most development potential of Chinese Medicine. In this study, biofilm formation by S. suis decreased after growth with 1/2 MIC, 1/4 MIC, or 1/8 MIC of Syringa oblata Lindl. aqueous extract and rutin. Scanning electron microscopy analysis revealed the potential effect of Syringa oblata Lindl. aqueous extract and rutin against biofilm formation by S. suis. Using iTRAQ technology, comparative proteomic analyses was performed at two conditions: 1/2 MIC of Syringa oblata Lindl. aqueous extract treated and non-treated cells. The results revealed the existence of 28 proteins of varying amounts. We found that the majority of the proteins were related to cell growth and metabolism. We also found that Syringa oblata Lindl. Aqueous extract affected the synthesis enzymes. In summary, Syringa oblata Lindl. aqueous extract might be used to inhibit the biofilm formation effectively by S. suis, and the active ingredients of the Syringa oblate Lindl. aqueous extract is rutin. The content of rutin is 9.9 ± 0.089 mg/g dry weight.

Role of Plant Leaves in Removing Airborne Dust and Associated Metals on Beijing Roadsides

ABSTRACTAs the capital of China, Beijing is continuously exposed to high amount of airborne dust, thus it is necessary to find improvement methods. Taking advantage of phytoremediation, an ecological and friendly way to improve air quality, this study investigates the role of urban plant leaves in removing airborne dust and its associated metals by analyzing leaf samples of 32 plant species in autumn. Results showed that leaves could remove dust from 0.510 to 23.0 g m–2 with an overall mean of 7.50 g m–2 on Beijing roadside sites. Some species removed certain metals more efficiently than others. Leaves of Chaenomeles speciosa accumulated the highest Cd (9.48 µg g–1) and the highest Cr value (19.8 µg g–1) was observed for leaves of Sorbaria kirilowii. Both of the highest concentrations of Cu (34.1 µg g–1) and Fe (868 µg g–1) appeared for leaves of Sophora japonica, whilst the highest values of Mn (169 µg g–1) and Ni (18.7 µg g–1) were found for leaves of Rosa chinensis and Prunus cerasifera f. atropurpurea, respectively. Populus beijingensis accumulated the most Pb (6.57 µg g–1) and Populus tomentosa the most Zn (142 µg g–1). For multi-metal pollution, Metal Accumulation Index (MAI) values were calculated, and the highest values were observed in unwashed leaves of Amygdalus persica (387), washed leaves of Punica granatum (105) and leaf dust of Viburnum sargentii (6.46). Plant species with dust accumulation rate above the mean including Koelreuteria paniculata, Ulmus pumila, Syringa oblata, Malus micromalu, Weigela florida cv. Red Prince, Ailanthus altissima, Salix babylonica, Robinia pseudoacacia, Ligustrum × vicaryi, Euonymus japonicus, Prunus cerasifera f. atropurpurea, Magnolia denudata, and species with higher MAI values including Amygdalus persica, Magnolia denudata, Syringa oblata are suggested to be considered in future green belt planning in Beijing.

植冠与土壤种子库储存种子的萌发特性及策略

PDF HTML阅读 XML下载 导出引用 引用提醒 植冠与土壤种子库储存种子的萌发特性及策略 DOI: 10.5846/stxb201608061617 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41371280，41501290）；黄土高原土壤侵蚀与旱地农业国家重点实验室开放基金（A314021402-1512）；辽宁省博士启动基金（201601368）；辽宁工程技术大学第五批生产技术问题创新研究基金（20160046T） Seed germination characteristics and strategies of seeds stored in canopy and soil seed banks Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为明确黄土丘陵沟壑区植物种子库如何调控种子萌发来提高个体适合度，选择研究区7种具有种子库的主要物种为研究对象，以刚成熟和室内储存种子为对照，比较植冠宿存（5个宿存期）和土壤埋藏（5a埋藏期）对植物种子萌发特性的影响，探讨植冠种子库与土壤种子库储存下的种子萌发策略。结果表明：7种植物种子经过不同种子库储存后萌发特性表现出明显的种间差异，黄刺玫（Rosa xanthina）和水栒子（Cotoneaster multiflorus）种子萌发力表现为植冠宿存不变型、土壤储存增强型，土壤储存明显提高水栒子种子萌发速率；达乌里胡枝子（Lespedeza davurica）和狼牙刺（Sophora davidii）种子萌发力表现为植冠宿存增强型、土壤储存减弱型，种子萌发历时表现为植冠宿存延长型，土壤种子库储存还可加快达乌里胡枝子萌发速率、缩短萌发历时；茭蒿（Artemisia giralaii）和铁杆蒿（Artemisia gmelinii），种子萌发率随植冠宿存时间先升高后降低，随土壤储存时间先降低后升高，土壤储存可推迟其萌发，铁杆蒿种子萌发速率在植冠与土壤储存后均加快；紫丁香（Syringa oblata）种子萌发率随植冠宿存先升高后降低，土壤储存明显加快其种子启动萌发与速率。在黄土丘陵沟壑区，植物种子经过植冠或土壤种子库储存，或增加、加快、提早萌发充分利用有利条件提高占据性，或减少、减缓、推迟萌发分摊不利条件的风险；而且该区植物植冠与土壤储存后种子萌发特性间的关系，体现各自适应环境与应对干扰的分工与协作策略，主要表现为：单一主导型和相辅相成型。 Abstract:To determine how seeds improve their individual fitness by regulating their germination characteristics, we selected seven species with obvious canopy and soil seed banks in the hill-gully Loess Plateau. Effects of the duration of canopy storage (five storage periods) and soil storage (burial periods of five years) on seed germination were analyzed, which were compared with seeds of just matured or stored in laboratory as control. And the germination strategies of seeds after storage in canopy seed bank and soil seed bank were discussed. Our results indicated that the seed germination characteristics of the seven species were obviously different after storage. For Rosa xanthina and Cotoneaster multiflorus, storage improved the seed germination ability of the soil seed bank but had no effect on that of the canopy seed bank, and the seed germination rates of the soil seed bank of the C. multiflorus was considerably increased. For Lespedeza davurica and Sophora davidii, storage improved the seed germination ability of the canopy seed bank but weakened that of the soil seed bank. Meanwhile, the seed germination lasting times of the canopy seed bank were prolonged after storage, whereas the seed germination rate and seed germination lasting times of the soil seed bank were accelerated and shortened for L. davurica, respectively. For Artemisia giralaii and A. gmelinii, seed germination percentages initially increased but then declined as the duration of canopy storage increased, whereas the seed germination rate initially declined and then increased. Storage of the soil seed bank also delayed the seed germination for both species, whereas storage of both the canopy and soil seed banks increased the seed germination rates of A. gmelinii. For Syringa oblate, seed germination percentages initially increased but then declined as the duration of canopy storage increased, and storage of the soil seed bank both increased the germination rates and promoted seed germination. In conclusion, seeds from the hill-gully Loess Plateau either (1) took full advantage of favorable conditions to finish regeneration in right time quickly by increasing germination percentage, speeding up seed germination rate and germinating at high concentration during the early stages of storage or (2) shared the risk of unfavorable conditions by reducing germination percentage, slowing down seed germination rate and deferring seed germination through seed storage in the canopy or soil seed bank. In addition, the relationship between seed germination characteristics of the canopy storage and that of soil seed bank storage indicated that plant use the division and cooperation storages of canopy and soil seed bank to adapt environments and to respond disturbance, which strategies mainly presented as single-dominant and tow-complementary patterns. 参考文献 相似文献 引证文献

A Study on the Characteristics of Water Consumption by Transpiration of Four Garden Plants in Linzhi City, Tibet

Characteristics of water consumption by transpiration of the four garden plants in the nursery of Agricultural and Animal Husbandry College of Tibet University has been studied using the 2-year-old potted seedlings. The experiment shows that: All of the four plants had a higher water consumption by transpiration in the full light condition than in the full shade condition. The four plants had a basically same process of water consumption in the two conditions: All of them had a lower value in the morning and evening, and a peak during noon 13:00-15:00. In the full light and shade conditions, the water consumption rate of the four plants represented the same sequencing: Sorbaria sorbifolia> Rosa chinensis Jacq.> Syringa oblata Lindl> Ligustrum quihoui Carr.. In the full light condition, all four plants had the maximal water consumption rate in August and minimal water consumption rate in December. Among them, the water consumption rate of Sorbaria sorbifolia in December accounted for 79.26% that of August, and the water consumption rate of Ligustrum quihoui Carr. in December accounted for 84.22% that of August.

Evaluation of drought-resistant physiological characteristics of roots and leaves for main greening tree species in Northwest Liaoning Province, China in spring.

In the present study, the effects of spring drought stress on physiological characteristics of leaves and roots for Populus alba, Ulmus pumila, Syringa oblata and Prunus sibirica were analyzed in Northwest Liaoning Province. The relationships between leaves and roots under drought stress were explored, and drought resistance of the four tree species was evaluated with the method of subordinate function and the gray correlative analysis. The results showed that there were significant differences in osmotic substances contents (soluble sugar, soluble protein and proline), antioxidative enzymes activities (SOD, POD and CAT) and malondialdehyde content among the four tree species and different organs (leaves and roots) (P<0.05). The average subordinative value in leaves increased in a sequence of P. sibirica (0.245), P. alba (0.346), S. oblata (0.412) and U. pumila (0.673), but it increased in roots in an order of U. pumila (0.315), P. sibirica (0.383), S. oblata (0.552) and P. alba (0.558). Meanwhile, the average subordinative value in leaves of P. alba, S. oblata and P. sibirica was lower than in roots, but it was higher in leaves than in roots of U. pumila. The association between physiological indexes and drought resistance showed an order of malondialdehyde > SOD > CAT > soluble protein > proline > soluble sugar > POD in leaves, and an order of malondialdehyde > soluble protein > soluble sugar > CAT > POD > proline > SOD in roots. These results indicated that the drought-resistant capability was different in leaves and roots of the four tree species. The roles of drought-resistance indexes were different between leaves and roots of the four tree species. Different management measures should be selected according to different organs of various tree species.

Insights into the differences in leaf functional traits of heterophyllous Syringa oblata under different light intensities

Many plants exhibit heterophylly; the spatially and temporally remarkable ontogenetic differences in leaf morphology may play an adaptative role in their success under diverse habitats. Thus, this study aimed to gain insights into differences in leaf functional traits of heterophyllous Syringa oblata Lindl., which has been widely used as an ornamental tree around the world under different light intensities in East China. No significant differences existed in specific leaf area (SLA) between lanceolate- and heart-shaped leaves. Differences in the investment per unit of light capture surface area deployed between lanceolate- and heart-shaped leaves may be not obvious. This may be attributing to the fact that single leaf wet and dry weight of heart-shaped leaves were significantly higher than those of lanceolate leaves but leaf length and leaf thickness of heart-shaped leaves were significantly lower than those of lanceolate leaves. The SLA of shade trees was significantly higher than that of sun trees. The investment per unit of light capture surface of shade trees was lower than that of sun trees, making it possible to increase light capture and use efficiency in low-light environments. The phenotypic plasticity of most leaf functional traits of lanceolate leaves was higher than those of heart-shaped leaves because the former is the juvenile and the latter is the adult leaf shape during the process of phylogenetic development of S. oblate. The higher range of phenotypic plasticity of leaf thickness and leaf moisture for sun trees may be beneficial to obtain a more efficient control of water loss and nutrient deprivation in high-light environments, and the lower range of phenotypic plasticity of single leaf wet and dry weight, and SLA for shade trees may gain an advantage to increase resource (especially light) capture and use efficiency in low-light environments. In brief, the successfully ecological strategy of plants is to find an optimal mode for the trade-off between various functional traits to obtain more living resources and achieve more fitness advantage as much as possible in the multivariate environment.

黄土丘陵沟壑区主要物种植冠种子库动态及其生态策略

PDF HTML阅读 XML下载 导出引用 引用提醒 黄土丘陵沟壑区主要物种植冠种子库动态及其生态策略 DOI: 10.5846/stxb201305101011 作者: 作者单位: 西北农林科技大学资源环境学院,中国科学院水利部水土保持研究所,水利部海河水利委员会海河流域水土保持监测中心站,中国科学院水利部水土保持研究所,西北农林科技大学林学院,西北农林科技大学水土保持研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 中国科学院重要方向项目(KZCX2-EW-406);国家自然科学基金重点项目(41030532). Dynamics and ecological strategies of aerial seed bank of main species in the hill-gully Loess Plateau Author: Affiliation: ollege of Resources and Environment, Northwest Agriculture and Forest University,Institute of Soil and Water Conservation, Chinese Academy of Sciences,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:植冠种子库是植物适应环境并应对外界干扰的种子生态策略之一,研究了黄土丘陵沟壑区12种主要植物植冠种子库动态,结果表明:杠柳不具有植冠种子库,其他11种植物均具有植冠种子库;除了黄刺玫种子在翌年5月达到脱落高峰,其他植物大部分种子在冬季脱落,其中杠柳、达乌里胡枝子、茭蒿、黄柏刺和水栒子的大部分种子脱落集中偏早,铁杆蒿和土庄绣线菊的大部分种子脱落集中偏晚;植冠宿存对大部分植物种子的萌发特性表现为促进作用;但不同植物种子的萌发时滞对植冠宿存响应差异较大;9种植物种子在植冠上宿存至翌年2月底,其种子活力仍能维持达60%以上;该区植物表现出不同的植冠种子库策略,通过不同的方式来减少干扰的威胁,提高成功萌发与更新的几率,它们或具有较大规模的宿存量、或调控种子萌发特性、或提高种子维持活力的百分比。此外,全面了解该区植物形成植冠种子库的机理及对应的生态策略还有待于全面、深入的研究。 Abstract:Delayed seed dispersal, leading to form an aerial seed bank, is one way to deal with disturbances in the special environment. Previous studies on aerial seed bank have focused on the fire-prone and arid desert habitats. However, there are few studies on aerial seed storage in the eroded slope habits, where lack of available soil water due to low soil water holding capacity caused by water erosion and drought. The dynamics of aerial seed banks, the seed germination and viability characteristics of 12 main species were studied in the hill-gully Loess Plateau, then the aerial seed bank strategies were analyzed which adapt the disturbances in the study region. The results showed that the seeds of Periploca sepium can't form aerial seed bank with no seed stored on plants until the end of the next February. While the seeds of the Rose xanthina can form the persistent aerial seed bank with seeds stored on plants until the next October. The other 10 species excepted Periploca sepium and Rose xanthina also can form aerial seed bank, which density are not significant high with percentages of seeds stored on plants below 5% up to the next May. Most seeds of the other 11 species dispersed during the winter, except the seeds of the Rose xanthina dispersed intensively until the next May. The seeds of the Periploca sepium, Lespedeza davurica, Artemisia giraldii, Berberis virgetorum and Cotoneaster multiflorus dispersed intensively earlier among 12 species while the seeds of the Artemisia gmelinii and Spiraea salicifolia dispersed intensively later among 12 species. Delayed seed dispersal promoted the ability of seed germination for most species. The cumulative percentage of seed germination rate reached the peak in December for Artemisia giraldii, Artemisia gmelinii and Hippophae rhamnoides, and at the end of the next February for Sophora davidii, Potentilla chinensis, Syringa oblata, Spiraea salicifolia, and in the next May for Lespedeza davurica. However, delayed seed dispersal reduced the ability of seed germination for the Berberis virgetorum. The seeds stored on plants belonged to different species need different time for seeds beginning to germinate. The seeds of nine species can retain on plants until the end of the next February, of which the percentage of seed with viability reached up to 60%. The percentages of the seeds with viability from five species were increased after stored on plants until the end of the next February. There were different aerial seed bank strategies for the species to deal with disturbances in the study region. The seeds avoided threaten from uncertainties of the erosion environments, then germinated and regenerated successfully by storing more seeds on the canopy, regulating the seed germination and increasing the percentage of viable seeds. Moreover, it's uncertain that weather the seeds can form aerial seed bank in different environments or in different years. The aerial seed bank types of some species varied as the environmental condition changed, which indicated that the aerial seed bank dynamics of some species had variability. Thus, more studies should be done in this field. 参考文献 相似文献 引证文献

Effects of stomatal development on stomatal conductance and on stomatal limitation of photosynthesis in Syringa oblata and Euonymus japonicus Thunb

During leaf development, the increase in stomatal conductance cannot meet photosynthetic demand for CO2, thus leading to stomatal limitation of photosynthesis (Ls). Considering the crucial influences of stomatal development on stomatal conductance, we speculated whether stomatal development limits photosynthesis to some extent. To test this hypothesis, stomatal development, stomatal conductance and photosynthesis were carefully studied in both Syringa oblata (normal greening species) and Euonymus japonicus Thunb (delayed greening species). Our results show that the size of stomata increased gradually with leaf expansion, resulting in increased stomatal conductance up to the time of full leaf expansion. During this process, photosynthesis also increased steadily. Compared to that in S. oblata, the development of chloroplasts in E. japonicus Thunb was obviously delayed, leading to a delay in the improvement of photosynthetic capacity. Further analysis revealed that before full leaf expansion, stomatal limitation increased rapidly in both S. oblata and E. japonicus Thunb; after full leaf expansion, stomatal limitation continually increased in E. japonicus Thunb. Accordingly, we suggested that the enhancement of photosynthetic capacity is the main factor leading to stomatal limitation during leaf development but that stomatal development can alleviate stomatal limitation with the increase of photosynthesis by controlling gas exchange.

ULTRASOUND-ASSISTED EXTRACTION OF TOTAL FLAVONOIDS FROM LEAVES OF SYRINGA OBLATA LINDL.

Leaves of Syringa Oblata Lindl. possess some important biological activities, such as antibacterial, antiviral, anti-inflammatory and antioxidant activities. These biological properties are mainly attributed to total flavonoids content. In this paper, ultrasound-assisted extraction of total flavonoids from leaves of Syringa Oblata Lindl. was studied. Effects of several experimental parameters, such as concentration of extracting solvent, ratio of liquid to material, extraction temperature, and time of sonication on extraction efficiencies of total flavonoids were evaluated. The best extraction conditions were: 1 g plant sample with 20 mL of 50% ethanol, at 60 °C for 50 min, obtaining a yield of total flavonoids of 92.00 ± 0.87 mg/g of plant. The results indicated that high amounts of total flavonoids can be extracted from leaves of Syringa Oblata Lindl. by ultrasound-assisted extraction technology.

Characteristics of blooming and pollen in flowers of two Syringa species (f. Oleaceae)

The observations were conducted in long-term sequence studies in the years 2006, 2009, 2013, in the Lublin area, Poland (51o 16’ N, 22o 30’ E). The flowering phenology, diurnal pattern of blooming, pollen production and insect visitation to the shrubs of &lt;em&gt;Syringa oblata &lt;/em&gt;Lindl. &lt;em&gt;var. dilatata &lt;/em&gt;(Nakai) Rehd. and &lt;em&gt;S. meyeri ‘Palibin’ &lt;/em&gt;Schn. were examined. &lt;em&gt;Syringa oblata &lt;/em&gt;var. &lt;em&gt;dilatata &lt;/em&gt;and &lt;em&gt;S. meyeri &lt;/em&gt;‘Palibin’ blo- omed from the mid May till mid June. The species are characteristic of early morning diurnal pattern of blooming, with approx. of 60% of daily instalment of flowers opened before 9.00 (GMT + 2h). Both species studied had the corolla tube 2-fold deeper during the pollen shedding phase compared to bud stage (mean = 14.9 mm ± 3.2 SD vs. 7.8 mm ± 2.8). No species effect was found for the size of anthers, for the mass of pollen produced in anthers and for the pollen viability. A constant number of 2 stamens in the flowers of &lt;em&gt;Syringa &lt;/em&gt;species entailed the pollen yield was derivative mainly to the number of developed flowers. Therefore significant differences were noted for the pollen yield between individual shrubs (mean 0.9 kg for &lt;em&gt;S. meyeri &lt;/em&gt;‘Palibin’, and 8.1 kg/ha for &lt;em&gt;S. oblata &lt;/em&gt;var. &lt;em&gt;dilatata &lt;/em&gt;). The &lt;em&gt;Syringa oblata &lt;/em&gt;var. &lt;em&gt;dilatata &lt;/em&gt;and &lt;em&gt;S. meyeri &lt;/em&gt;‘Palibin’ due to their attractive flowering period, and the abundance of blooming are suitable for different ornamental designs in urban areas. Unfortunately, despite the entomophilous flower traits, the insect visitors appeared sporadically.

Pseudocercospora lilacis . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Pseudocercospora lilacis , a parasitic fungus causing leaf spots on living leaves of ornamental plants in the genera Ligustrum and Syringa . Some information on its habitat, dispersal and transmission, and conservation status is given, along with details of its geographical distribution (North America (USA (Alabama, Florida, Maine, Minnesota, Mississippi, South Carolina and Texas)), South America, Asia (China (Henan), Japan and Russia (Primorye krai)), Atlantic Ocean (Bermuda) and Europe (Austria, Belarus, Belgium, France, Germany, Italy, Lithuania, Russia (Kursk oblast and Ulyanovsk oblast) and Ukraine)) and hosts ( Ligustrum japonicum, L. lucidum, L. sinense, Ligustrum sp., Syringa oblata (also as S. oblata var. affinis ), S. persica, S. reticulata subsp. amurensis (as S. amurensis [ S. reticulata ]), S. reticulata var. mandshurica, S. vulgaris and Syringa sp.).

A comparison of pressure–volume curves with and without rehydration pretreatment in eight woody species of the semiarid Loess Plateau

Pressure–volume (P–V) curves are frequently used to analyze water relation properties of woody plants in response to transpiration-induced tissue water loss. In this study, P–V analyses were conducted on eight woody species growing in the semiarid Loess Plateau region of China during a relatively dry summer season using both the recently recommended instantaneous measurement and the traditional method with rehydration pretreatment. Generally, P–V-derived parameters in this study reflected conditions in a dry growth environment. Species-specific differences were also found among P–V parameters, suggesting each species uses different mechanisms to respond to drought. Based on the results from instantaneous measurements, a descending sequence for drought tolerance ranked by water potentials at the turgor loss point (Ψtlp) was Rosa hugonis > Syringa oblata = Armeniaca sibirica > Caragana microphylla > Pyrus betulaefolia > Acer stenolobum > Quercus liaotungensis > Robinia pseudoacacia. The first five species also showed lower levels of osmotic potential at full turgor (Ψ π sat ) and higher symplastic osmotic solute content per dry weight, suggesting they possess advantages in osmotic adjustment. Also, this study supports previous reports noting rehydration pretreatment resulted in shifts in P–V parameters. The magnitude of the shifts varied with species and water conditions. The effect of rehydration was stronger for species with higher drought tolerance or subjected to the influence of drought. Differences in the parameters among species were mitigated as a result of rehydration. Those with a lower Ψtlp or midday water potential were more deeply affected by rehydration. Application of instantaneous measurements was strongly recommended for proper analysis of P–V curves particularly in arid and semiarid areas.

Responses of leaf gas exchange, water relations, and water consumption in seedlings of four semiarid tree species to soil drying

To understand the response patterns to soil drying and the water use properties of commonly reforested trees in the semiarid Loess Plateau region of China, a glasshouse experiment was carried out with the seedlings of four species, i.e., Robinia pseudoacacia, Armeniaca sibirica, Syringa oblata, and Quercus liaotungensis. Severe water stress induced by withholding water resulted in permanent wilting of most of the seedlings pot-cultured with sandy soil in 8-12 days. Predawn and midday leaf water potentials and gas exchange characteristics (e.g., stomatal conductance) in the seedlings did not show marked changes until the volumetric soil water content decreased to about 0.05. As the soil water content decreased further, these physiological parameters rapidly declined, approaching their minimal levels at the stage of permanent wilting. The response of each parameter to soil water content changes was fitted with a non-linear saturation curve. Though the results suggested that the general pattern of responses to soil drying was identical among the species, quantitative differences in drought tolerance and water use properties were detected. Leaf stomatal conductance in R. pseudoacacia and A. sibirica showed earlier responses to reduced predawn leaf water potentials. However, water use characteristics and specific leaf area indicated that these two species consumed more water and may not be as drought tolerant as S. oblata and Q. liaotungensis. These results may provide important information to compare the reforestation species with respect to soil drying.

First Report of Syringa oblata and S. reticulata Leafroll Disease in China.

Syringa oblata is an important ornamental tree widely grown in China. In September of 2008, S. oblata plants exhibiting symptoms of leafroll and yellowing were found in a garden on the Northwest A&F University campus. Samples were collected from this site. Total DNA was extracted from 0.5 g of phloem tissue from leaf midribs and stems of each sample. DNA samples were analyzed with a nested PCR assay using phytoplasma 16S rDNA universal primers R16mF2/R16mR1 followed by specific primers R16F2n/R16R2 (1), which amplified a 1,452- and 1,246-bp product, respectively. We tested all 30 lilac samples, 20 of which had symptoms of leafroll and yellowing. These produced the expected 1,452- and 1,246-bp PCR products In contrast, the remaining 10 samples from symptomless trees yielded no PCR products. We also surveyed another lilac variety (Syringa reticulata), which is widely grown on the campus, and tested 50 samples with the above method. Again, 1.4- and 1.2-kb PCR products were amplified from all 30 trees displaying leafroll and yellowing symptoms, but not from the other 20 samples from symptomless trees. A comparative analysis of sequences derived from the two hosts showed that the phytoplasmas infecting them were most similar (>99%) to paulownia witches'-broom (PaWB) phytoplasma (GenBank Accession No. EF199937). Restriction fragment length polymorphism (RFLP) analysis of the nested 1.2-kb 16S rDNA products with endonucleases AluI and MseI indicated that all symptomatic plants were infected by the phytoplasmas belonging to aster yellow group (16SrI) subgroup D (16SrI-D) PaWB phytoplasma (2). 16S rDNA sequence comparisons and RFLP analysis of the cloned 16S rDNA from S. oblata (GenBank Accession No. FJ445224) and S. reticulate (GenBank Accession No. FJ445225) indicated that the phytoplasmas infecting them were nearly identical (99.8% identity). To our knowledge, this is the first report of the presence of the phytoplasma associated with a leafroll disease of S. oblata and S. reticulata in China.

Host Specificity of &lt;I&gt;Argopistes tsekooni&lt;/I&gt; (Coleoptera: Chrysomelidae), a Potential Biological Control Agent of Chinese Privet

Chinese privet, Ligustrum sinense Lour., is a perennial semi-evergreen shrub that is a serious invasive weed in the United States. Classical biological control offers the best hope for controlling it in an economic, effective, and persistent way. Host specificity of one of the most promising biological control agents of Chinese privet, a flea beetle, Argopistes tsekooni Chen (Coleoptera: Chrysomelidae), was evaluated in China by using laboratory no-choice and choice tests on 13 species of Oleaceae and eight species in other families that have important economic value. In adult no-choice survival and oviposition tests, the flea beetle fed and survived for 30 d on Syringa oblata Lindl., Jasminum nudiflorum Lindl., and three species in the genus Ligustrum. Females also oviposited on these species, but only larvae from eggs laid on S. oblata and Ligustrum spp. developed successfully. In addition, the beetles did not feed or oviposit on the species of economic importance. In choice tests, adults preferred L. sinense for feeding and oviposition. These results show that A. tsekooni is relatively host specific and warrants further testing as a biocontrol agent of Chinese privet in the United States.

Assessment of the effect of a fully closed hillside afforestation mode on the natural Pinus tabulaeformis forest

The Huanglong Mountain forest zone is one of the major natural secondary forest zones in the southern Loess Plateau in Shaanxi Province, China. Since 1950, a mode of fully closed hillside afforestation (FHA) has been applied in the forest. On some special sites, the forest age exceeds 80 years. Pinus tabulaeformis forests form the most important vegetation cover in the warm temperate regions of China. Similarly, populations of P. tabulaeformis are dominant in existing forest ecosystems. Quercus liaotungensis, Syringa oblata, Populus davidiana, Prunus davidiana, Betula platyphylla and Toxicodendron vernicifluum can be occasionally found in the tree layer and shrub species are abundant. Based on the data collected from 31 plots and 93 soil samples, the state of health of the forest ecosystem is discussed and the appropriate FHA age has been determined. Twelve indices representing vegetation and soil properties in natural, secondary P. tabulaeformis forest ecosystems were generated by sensitivity analysis and an assessment index system for the FHA mode was established. According to the equal distance method, a clustering technique and five grades of an integrated index for evaluating the FHA mode were compartmentalized. The effect of the FHA mode on natural secondary P. tabulaeformis forests was evaluated by an integrated index method with the aid of an analytical hierarchy process (AHP). The results are as follows: values of the integrated index in the FHA mode of 16, 25, 30, 45, 60 and 75 year old stands were 7.25, 6.88, 7.82, 5.51, 4.78 and 2.79 respectively. With an increase over age of the FHA stands, the effect of the FHA mode deteriorated. We conclude that natural forests should not be protected in the FHA way after 45 years. At that stage, mixing suitable tree species, selection cutting and other silvicultural and management measures should be adopted.

Effects of soil drought on seedling growth and water metabolism of three common shrubs in Loess Plateau, Northwest China

The growth and water metabolism of three common shrubs on the Loess Plateau were studied under soil with different water contents. Results showed that water consumption of those species decreased with the increase in drought stress, and water consumptions of these shrubs were different: Forsythia suspensa was the greatest, and Syringa oblata was the lowest. The growth rate of new branches and leaf area of three species were the fastest under adequate soil water conditions, and were the lowest under severe drought. Under the same water conditions, the growth of F. suspensa was the fastest while that of S. oblata was the slowest. The water content, proline and chlorophyll content of different species changed with the increase in soil water stress. The leaf water content of Periploca sepium and F. suspensa was obviously higher than that of S. oblata, while the leaf proline content of F. suspensa and S. oblata was lower than that of P. sepium. The ratio leaf chlorophyll a: b of F. suspensa and S. oblata decreased with the decrease in soil water content. Although these three shrubs had different mechanisms in response to drought stress, they all had higher drought resistance and could adapt to the drought condition on the Loess Plateau. This paper provided some bases for choosing tree species on the Loess Plateau.

Syringa oblata Lindl var. alba as a source of oleuropein and related compounds

AbstractThe leaf methanol extract of Syringa oblata Lindl var. alba was investigated as a source of oleuropein and related compounds. The extract had a high total phenol content and a radical scavenging activity similar to that of the respective extract from Olea europaea leaves. HPLC‐DAD characterisation of the two most abundant phenolic compounds in the extract of S. oblata indicated that both had UV spectra matching that of oleuropein. The presence of oleuropein was verified by using LC‐MS. Identification of the second compound was only feasible after isolation (preparative HPLC) and spectroscopic characterisation [LC‐MS, 1H NMR and homonuclear two‐dimensional correlated spectroscopy (COSY)]. The compound identified was the known bioactive syringopicroside. On the basis of MS data other peaks were assigned to oleuropein aglycone, verbascoside, ligstroside and syringopicroside derivatives, as well as to a luteolin rutinoside. The findings are promising for the potential exploitation of S. oblata leaf extract as a source for oleuropein and other bioactive ingredients. Copyright © 2006 Society of Chemical Industry

Physicochemical characteristics of ambient particles settling upon leaf surfaces of urban plants in Beijing

Particulate pollution is a serious health problem throughout the world, exacerbating a wide range of respiratory and vascular illnesses in urban areas. Urban plants play an important role in reducing particulate pollution. Physicochemical characteristics of ambient particles settling upon leaf surfaces of eleven roadside plants at four sites of Beijing were studies. Results showed that density of particles on the leaf surfaces greatly varied with plant species and traffic condition, Fraxinus chinensis, Sophora japonica, Ailanthus altissima, Syringa oblata and Prunus persica had larger densities of particles among the tall species. Due to resuspension of road dust, the densities of particles of Euonymus japonicus and Parthenocissus quinquefolia with low sampling height were 2—35 times to other taller tree species. For test plant species, micro-roughness of leaf surfaces and density of particles showed a close correlation. In general, the larger micro-roughness of leaf surfaces is, the larger density of particles is. Particles settling upon leaf surfaces were dominantly PM 10 (particulate matter less than 10 μm in aerodynamic diameter; 98.4%) and PM 2.5 (particulate matter less than 2.5 μm in aerodynamic diameter; 64.2%) which were closely relative to human health. Constant elements of particles were C, O, K, Ca, Si, Al, Mg, Na, Fe, S, Cl and minerals with higher content were SiO 2, CaCO 3, CaMg(CO 3) 2, NaCl and 2CaSO 4·H 2O, SiO 2. CaCO 3 and CaMg(CO 3) 2 mainly came from resuspension of road dust. 2CaSO 4·H 2O was produced by the reaction between CaCO 3 derived from earth dust or industrial emission and SO 2, H 2SO 4 or sulfate. NaCl was derived from sea salt.

Advance of tree-flowering dates in response to urban climate change

An increase in temperature due to greenhouse effects is manifest in the changes in diurnal, annual and inter-annual patterns, which may alter phenological events in plants. Flowering dates of four tree species, Prunus davidina, Prunus armeniaca, Robinia pseudoacacia and Syringa oblata, were significantly advanced in response to temperature increase over the years 1950–2004 in Beijing, China, due to the impact of urban climate warming. Because both climate warming and the urban heat island effect in winter and early-spring were more rapid than in late-spring and early summer, the dates in early flowering species advanced more quickly than in late flowering species. The early flowering species, P. davidina, advanced by 2.9 days/decade, while the other species advanced by 1.5–2.0 days/decade during 1950–2004. Therefore, the intervals between flowering dates of different species were expanded. P. davidina, flowering in early-spring, was much more sensitive to minimum and average temperatures (2.88–2.96 days/°C), but less sensitive to maximum temperature (2.46 days/°C). R. pseudoacacia, flowering late in the warmer season, was more sensitive to average and maximum temperatures (2.45–2.89 days/°C), but less sensitive to minimum temperature (1.91 days/°C). Statistical analysis showed that, in Beijing, plant flowering is most sensitive to average temperature over 30 days before average blossom date. On the basis of the temperature response curve, the goodness of fitting demonstrates that spring flowering dates can be predicted from the period when temperature is over 0 °C.