Effects of metal lead on growth and mycorrhizae of an invasive plant species (Solidago canadensis L.)

It is less known whether and how soil metal lead （Pb） impacts the invasion of exotic plants. A greenhouse experiment was conducted to estimate the effects of lead on the growth and mycorrhizae of an invasive species （Solidago canadensis L.） in a microcosm system. Each microcosm unit was separated into HOST and TEST compartments by a replaceable mesh screen that allowed arbuscular mycorrhizal （AM） fungal hyphae rather than plant roots to grow into the TEST compartments. Three Pb levels （control, 300, and 600 mg/kg soil） were used in this study to simulate ambient soil and two pollution sites where S. canadensis grows. Mycorrhizal inoculum comprised five indigenous arbuscular mycorrhizal fungal species （ Glomus mosseae, Glomus versiform, Glomus diaphanum, Glomus geosporum, and Glomus etunicatum）. The ^15N isotope tracer was used to quantify the mycorrhizally mediated nitrogen acquisition of plants. The results showed that S. canadensis was highly dependent on mycorrhizae. The Pb additions significantly decreased biomass and arbuscular mycorrhizal colonization （root length colonized, RLC%） but did not affect spore numbers, N （including total N and ^15N） and P uptake. The facilitating efficiency of mycorrhizae on nutrient acquisition was promoted by Pb treatments. The Pb was mostly sequestered in belowground of plant （root and rhizome）. The results suggest that the high efficiency of mycorrhizae on nutrient uptake might give S. canadensis a great advantage over native species in Pb polluted soils.

Changes of Soil Microbiological Characteristics After Solidago canadensis L. Invasion

The relationship between Solidago canadensis L. invasion and soil microbial communities was studied across the invasive gradients varying from 0 to 40, 80, and 100% coverage of S. canadensis. The results showed both soil microbial biomass C （Cmic） and N （Nmic） increased as the coverage of S. canadensis increased. Soil microbial quotient Cmic/Corg （microbial biomass C/organic C） tended to increase linearly with the coverage of S. canadensis. Soil basal respiration （BR） also showed a similar trend. The soil respiratory quotient qCO2 decreased with S. canadensis invasion, and remained at quite a constantly low level in the invasive soils. Sole carbon source utilization profiles analyses indicated that S. canadensis invasion tended to result in higher microbial functional diversity in the soil. Average utilization of specific substrate guilds was highest in the soil with S. canadensis monoculture. Principle component analysis of sole carbon source utilization profiles further indicated that microbial functional diversity in the soil with S. canadensis monoculture was distinctly separated from those soils in the native area and the ecotones. In conclusion, S. canadensis invasion improved soil microbial biomass, respiration and utilization of carbon sources, and decreased qCO2, thus created better soil conditions, which in turn were more conducive to the growth of S. canadensis.

2-Steps Preparation Activated Carbon from Solidago Canadensis:Carbonized by Electrial heating and Activated by Microwave Radiation

The activated carbon(AC)was prepared from Solidago Canadensis(SC),an alien invasive plant.The plant was firstly carbonized under nitrogen at 400 ℃ for 90 min in an electrical furnace,and then the carbonized product was activated with KOH through microwave radiation.Effects of KOH/C ratio,microwave power,microwave radiation time on the adsorption capacities and yield of AC were evaluated.It indicated that the optimum conditions were KOH/C ratio 2 g/g,microwave power 700 W,and microwave radiation time 6 min.The carbonation process of SC was analyzed by thermogravimetry(TG).The pore structural parameters and surface functional groups of the AC were characterized by nitrogen adsorption-desorption and Fourier Transformed Infrared Spectroscopy(FTIR),respectively.The activation yield,the surface area,the average pore size,and the average micropore size of AC prepared from optimum conditions were 53.75%,1 888 m2/g,0.567 nm,and 0.488 nm,respectively.The adsorption amounts of AC were 302.4 mg/g for methylene blue and 1 470.27 mg/g for iodine.

Is root nutrient uptake a modular function? A test using Solidago canadensis

Plant roots have been recognized to be modu- lar, and a third order root cluster has been proposed to be the basic root module unit based upon the life cycle. This experiment examines root modularity of the nutrient-up- take function using stable isotope 15N. Solidago canadensis root clusters of second or third orders--from the same third or fourth order roots, respectively--were treated with 15NH15NO3, NH4NO3, and de-ionized water for 15 and 180 min. The δ15N values of the root clusters were then analyzed and compared. The 15N values of 15N-treated root clusters of both second and third orders were hundreds of times higher than that of the 15N untreated root clusters. However, the differences of the δ15N values among 15N untreated root clusters （though expressed some significant variations）, did not indicate the 15N shared by the sister root clusters came from a common higher-order root. These results demonstrated functional modularity of root nutrient uptake, revealed a second order root, perhaps even a first order root to be a base module unit in terms of root nutrient uptake. The results also suggested that the concept of root modularity is function-specific. This experiment further revealed the importance of treatment timing in stabilizing the internal 15N/14N ratio in roots and avoiding top-down transportation of 15N back into roots to secure unbiased measurements.

Application and Characterization of Cellulose Acetate Membrane Produced from Herbaceous Plant: Solidago Canadensis L.

In this work,the viability of Solidago Canadensis L. for cellulose acetate membrane production was tested. The cellulose was extracted from Solidago Canadensis L. stem by organic solvents,and the cellulose diacetate was obtained by acetylization of cellulose. The properties of the intermediate products of cellulose pulp and cellulose diacetate were characterized by FT-IR and XRD. Compared with commercial cellulose diacetate,the properties of cellulose diacetate were similar to those of the commercial cellulose diacetate. The cellulose acetate membrane with desirable pure water flux and rejection rate was obtained from cellulose diacetate by solution casting. The membrane showed favorable hydrophilic property so that it had good anti-pollution performance. The maximum pure water flux of the membrane was 27. 21 m L /( cm2· h) and the maximum rejection rate was 80. 39%. The results demonstrated that the membrane obtained from herbaceous plant: Solidago Canadensis L. had good performance of ultrafiltration.

Development of Granule Composition Based on the Total Evaporated Extract of Bidens Tripartita, Solidago Canadensis and Agrimonia Eupatoria Herbs

The aim of the study is the development and standardization of granules in hard gelatin capsules based on the composition of dry extracts of Bidens tripartita L.,Solidago canadensis L.and Agrimonia eupatoria L.Herbs,possessing nephroprotective activity and antifibrotics in toxic nephropathies.Developed the structure and defined the quality indicators of the pellets with dry extracts of Bidens tripartita L.,Solidago canadensis L.and Agrimonia eupatoria L.herbs.The quality specification for the drug-granules of the composition of dry extracts in solid gelatin capsules is developed.

Elevated nitrogen deposition may advance invasive weed, Solidago canadensis, in calcareous soils

Aims change in nitrogen(N)availability regulates phosphorus(P)acquisition and potentially alters the competition among native species and invasive weeds.this study determines how current and pro-jected N deposition affect the growth,the intraspecific and interspe-cific competitive ability of native and invasive plants in calcareous soils with low P availability.Methods A controlled greenhouse experiment was conducted using spar-ingly soluble hydroxyapatite(HAP)to simulate the calcareous soils with low P availability.the growth and competitive intensity be-tween an invasive weed(Solidago canadensis)and a native weed(Pterocypsela laciniata)exposed to two levels of N addition repre-sentative of current and future N deposition in china were experi-mentally determined.Important Findings P acquisition and the growth of both S.canadensis and P.laciniata growing alone significantly increased with increasing N level.However,the effect of N addition was reduced when intraspecific or interspecific competition existed.N addition altered the com-petitive relationship between S.canadensis and P.laciniata allowing S.canadensis to out-compete P.laciniata due to variation in P ac-quisition from HAP.Elevated N deposition might assist the invasion of S.canadensis in the widely distributed calcareous soils under environmental changes.

Reproductive biology in an invasive plant Solidago canadensis

Solidago canadensis,a perennial Compositae plant originating from North America,was introduced into China as a horticultural plant in 1935.Under natural condi-tions,S.canadensis allocates large amounts of energy to sexual reproduction and produces many seeds,which reflects an r-strategy with high seed number and small seed size.In addition,naturalized populations have a great capacity to grow clonally with underground stems.S.canadensis has become an invasive weed in eastern China,and has caused serious damages to agricultural production and ecosystems in several provinces in China.In order to understand the reproductive characteristics of S.canadensis and effectively control its spread,we examined soil conditions,seed charac-teristics,seed germination and the capacity for asexual reproduction in different plant parts.We investigated the population dispersion of S.canadensis in fixed sites for three years,and analyzed the seasonal dynamics of the morphological parameters of the underground parts and the caloric values of different organs of S.canadensis.We also compared differences in the root systems of S.canadensis and composite exotic weeds.The following results were obtained:1)Under natural conditions,the germination season of S.canadensis lasts from March to October,with a peak from April to May.Vegetative growth and asexual reproduction are especially vigorous during summer due to high temperatures and soil drought stress.On the other hand,the rainy season proves suitable for seed germination.Most S.canadensis flower between September and January,and fruit in late October.A mature plant can produce about 20000 seeds.The mean weight of 1000 seeds ranges from 0.045 g to 0.050 g,and the mean seed moisture content ranges from 60%to 80%.The light-winged seeds disperse readily by air,water,vehicles,human activity or through livestock.2)S.canadensis seeds have a wide tolerance for different values of pH,salinity and soil moisture.The mean percent germination of seeds is 30%under suitable conditions.The results of seed germination under various environmental stresses and investigation of soil conditions indicate that well-aerated,slightly acidic soils with low salinity are suitable for the growth of S.canadensis.Additionally,S.canadensis has a high tolerance for contamination by heavy metal elements including Zn,Cu and Pb,but has low accumulation coefficients for these elements.3)S.canadensis reproduces asexually via underground rhizomes and nodes on the stem base to recruit new individuals,and in plants that experience mechanical damage,this repro-ductive strategy is used to produce clonal shoots.The capacity for asexual reproduction among different plant parts rank as follows:underground parts>stem-base(20 cm)>stem-base(30 cm)>stem-base(45 cm)>stem.Further,with increasing mechanical damage,the quantity of shoots produced by the plant decreases.4)The morphological parameters of the root system of S.canadensis including length,surface area,volume,and average diameter are greater than for composite exotic weeds.These parameters indicate that S.canadensis has the physiological potential to widely invade China.5)The aboveground growth rate and most of the underground morphological parameters vary remarkably among the seasons,with a peak normally occurring in September.In August,a fraction of the energy in leaves and stems is allocated underground to increase fine root growth and water uptake during hot weather.Additionally,the seasonal dynamics of the underground morphological parameters and the caloric values of different organs of S.canadensis enhance its reproductive ability.Based on the results above,we conclude that S.canadensis has great invasive potential in China.We suggest that urgent measures should be taken to control its further spread,and to minimize its impact on local plant diversity.

Warming and elevated nitrogen deposition accelerate the invasion process of Solidago canadensis L.

Background:Invasive species can threaten native diversity and alter ecosystem processes while interacting with other components of global environmental change.Invasive plants are becoming increasingly problematic and this can be stimulated by changes in the environment.However,existing studies have primarily investigated the effects of environmental change on a specific stage of plant invasion rather than the continuous invasion process.Methods:A space-for-time substitution experiment was performed to investigate how warming and nitrogen deposition affects the invasion process of a plant.Specifically,different ratios of invasive Solidago canadensis L.to native Artemisia argyi Levl.et Van were employed as a proxy to represent successive levels of invasion.A total of seven treatments were applied in the experiment:ambient(CK),N addition(+5,+12 g m^(−2)year^(−1)),warming(+1.15,+1.86℃)and their interaction(5 g N m^(−2)year^(−1)+1.15℃,12 g N m^(−2)year^(−1)+1.86℃).The growth performance and competitiveness of S.canadensis were investigated.Results:The competitiveness of Solidago canadensis decreased linearly with its invasion degree(p<0.05).Non-linear regression showed that S.canadensis invasion levels of 53%,53%,68%,55%and 58%were the critical thresholds for shifting the direction or magnitude of chlorophyll,leaf nitrogen,leaf shape index,diameter,and root/shoot ratio,respectively.Compared with the ambient treatment(CK,no warming and no N addition),the diameter,height,bio-mass and relative competitiveness of S.canadensis were each limited by warming,to a certain extent,whereas these and the above parameters were significantly increased by nitrogen deposition.The interaction of increased temperature and nitrogen deposition led to significant increases in the growth and competitiveness of S.canadensis,and this effect was detected in every stage of the invasion,throughout the invasion process.Conclusions:Environmental change might have a continuous,progressive,and augmentative effect on the phenotypic traits of S.canadensis.This study provides fairly robust evidence that environmental change promotes the invasion process of S.canadensis in general,not simply in specific stages.In the future,rather than focusing on specific stages,experimental studies should consider examining invasion on a broader scale.

重度干旱降低两种菊科入侵植物凋落物共同降解的速率

当前,中国已分布的入侵植物隶属于菊科的种类数量最多。更关键的是,两种入侵植物可以在同一生境中形成共同入侵。此外,干旱可以影响入侵植物的凋落物降解和土壤酶活性。基于此,本研究旨在解析干旱背景下两种菊科入侵植物鬼针草(Bidens pilosa)和加拿大一枝黄花(Solidago canadensis)对凋落物降解和土壤酶活性的单一影响和复合影响。本研究主要通过聚乙烯凋落袋实验完成,其中每一个凋落袋装入5 g入侵植物鬼针草的凋落物,或装入5 g入侵植物加拿大一枝黄花的凋落物,或装入5 g两种菊科入侵植物鬼针草和加拿大一枝黄花等比例混匀的凋落物。干旱处理水平设置为:对照、轻度干旱和重度干旱。实验结束后测定两种菊科入侵植物凋落物单一降解速率和共同降解速率以及土壤酶活性。两种菊科入侵植物凋落物共同降解对土壤脲酶活性的影响为叠加效应。两种菊科入侵植物凋落物共同降解速率以及入侵植物鬼针草凋落物单一降解速率显著高于入侵植物加拿大一枝黄花凋落物单一降解速率。轻度干旱显著增加土壤脲酶活性,但重度干旱显著降低土壤脲酶活性。重度干旱显著降低两种菊科入侵植物凋落物共同降解速率以及入侵植物鬼针草凋落物单一降解速率,但干旱处理未显著影响入侵植物加拿大一枝黄花凋落物单一降解速率。因此,重度干旱可能通过减缓营养循环速率显著影响两种菊科入侵植物共同入侵进程以及入侵植物鬼针草单一入侵进程,但并未显著影响入侵植物加拿大一枝黄花单一入侵进程。

纬度和土壤微生物对入侵植物加拿大一枝黄花对共同进化的专性食草昆虫抗性的影响

在全球化的背景下,入侵植物再次暴露在来自其原产地的专性食草动物面前的可能性越来越大。然而,入侵植物对曾共同进化的专性食草动物的抗性是否存在纬度趋势以及土壤微生物如何影响入侵植物对这类食草动物的抗性还鲜有研究。我们假设入侵植物加拿大一枝黄花(Solidago canadensis)对其曾共同进化的来自原产地的食草昆虫菊方翅网蝽(Corythucha marmorata)的抗性随纬度的增加而增加,而加拿大一枝黄花的局部根际微生物可以促进加其对菊方翅网蝽的抗性。为了验证上述假设,我们首先通过野外调查和温室实验,研究了菊方翅网蝽在中国加拿大一枝黄花种群中的分布丰度,以及对加拿大一枝黄花造成的危害是否存在纬度分布规律。其次,我们通过温室实验,检测了加拿大一枝黄花的本地根际土壤微生物是否能促进加拿大一枝黄花对菊方翅网蝽的抗性。研究结果表明,菊方翅网蝽在加拿大一枝黄花中的分布密度和对加拿大一枝黄花的危害程度与纬度以及加拿大一枝黄花的生长呈现正相关,说明加拿大一枝黄花对菊方翅网蝽的抗性具有纬度趋势。然而,在温室实验中,来自不同纬度的加拿大一枝黄花受到菊方翅网蝽的伤害程度没有显著差异。此外,当根际土壤和加拿大一枝黄花的根状茎同时来自于野外被轻度危害的加拿大一枝黄花或同时来自于野外被重度危害的加拿大一枝黄花时,加拿大一枝黄花的抗性最强。这一结果表明,加拿大一枝黄花的局部根际土壤微生物促进了加拿大一枝黄花对菊方翅网蝽的抗性。

丛枝菌根真菌对加拿大一枝黄花生长的影响不受氮形态的调节

越来越多的研究结果表明,入侵植物能通过改变土壤真菌群落直接或间接的促进自身生长。土壤氮含量高低影响植物与丛枝菌根真菌(AMF)的共生关系,进而影响植物生长。然而,氮形态是否会改变入侵植物-相互作用,以及被改变的AMF群落是否影响入侵植物和本地植物对不同氮形态的依赖性尚未可知。鉴于此,本研究以加拿大一枝黄花(Solidago canadensis)为研究对象,结合野外驯化和室内接种实验,探讨了群落水平上该入侵植物的生长,以及入侵植物-AMF相互作用对不同形态氮添加的响应。首先,选择30对加拿大一枝黄花入侵群落和相近的非入侵群落,并用湿筛法从土壤中获取入侵AMF孢子和非入侵AMF孢子,同时构建两种人工群落:加拿大一枝黄花群落(N=4)和本地植物群落(N=4);然后将入侵和非入侵AMF孢子接种至两种人工群落中,并在生长期间分别供应3种形态氮(NO3-N、NH4-N、Gly-N);生长结束后收获各植物群落地上、地下生物量,测定加拿大一枝黄花的形态特征。研究结果发现,加拿大一枝黄花未表现出显著的氮形态依赖性,本地植物则表现出较弱的氮形态依赖性;但入侵AMF可消除氮形态对本地植物的影响。在无氮源供应时,AMF不影响两种植物群落的生长,而提供任一形态氮源时,入侵AMF均显著促进该入侵植物的地下生物量和总生物量而不改变本地植物的生长。加拿大一枝黄花-AMF正相互作用强度显著大于本地植物-AMF相互作用的强度,且这种正的相互作用是通过直接或间接调节加拿大一枝黄花的表型特征(如株高、叶数、根状茎数量等)来实现的。该研究强调了植物-AMF相互作用在入侵中的重要性,并揭示了加拿大一枝黄花特殊的氮获取策略,为进一步研究入侵机制提供了重要的依据。

基质有效性调节加拿大一枝黄花入侵对土壤呼吸的抑制作用

外来植物入侵不仅会降低河边近岸湿地生态系统植被多样性,而且会改变湿地生态系统的地下碳过程。外来入侵植物加拿大一枝黄花(Solidago canadensis L.)已广泛入侵我国东南部地区,但加拿大一枝黄花入侵对入侵地生态系统地下土壤碳循环过程的影响却知之甚少。本研究通过野外原位观测实验和温室模拟入侵实验,探究外来植物加拿大一枝黄花入侵对入侵地土壤呼吸的影响规律及其驱动因素。野外原位观测实验开展于2018年7月21日至12月15日,期间每周测定样地土壤呼吸。温室模拟入侵实验开展于2019年7月15日至12月15日,期间每月1日与15日上午测定土壤呼吸、自养呼吸和异养呼吸。土壤呼吸、自养呼吸和异养呼吸通过静态箱结合深埋根系隔离法测定。野外原位观测实验和温室模拟入侵实验结果均显示,加拿大一枝黄花的入侵降低了土壤二氧化碳的排放通量。加拿大一枝黄花入侵对土壤呼吸的抑制作用可能归因于其入侵引起的土壤可利用底物质量与数量的变化,表明外来入侵植物加拿大一枝黄花可通过改变植物释放基质以及与本地植物和/或土壤微生物争夺土壤有效基质而影响土壤碳循环。这些研究结果对于评估外来入侵植物对入侵地地下碳动态的影响以及对全球变暖的贡献具有重要意义。