Changes in Soil Biota Resulting from Growth of the Invasive Weed, Ambrosia artemisiifolia L.(Compositae), Enhance Its Success and Reduce Growth of Co-Occurring Plants

Exotic plant invasion presents a serious threat to native ecosystem structure and function. Little is known about the role of soil microbial communities in facilitating or resisting the spread of invasive plants into native communities. The purpose of this research is to understand how the invasive annual plant Ambrosia artemisiifolia L. facilitates its competition capacity through changing the structure and function of soil microbial communities. The soil characteristics of different areas invaded by A. artemisiifolia were examined. Greenhouse experiments were designed to assess the effect of A. artemisiifolia invasion-induced changes of soil biota on co-occurring plant growth, and on the interactions between A. artemisiifolia and three co-occurring plant species. The results showed that the soil organic C content was the highest in heavily invaded sites, the lowest in native plant sites, and intermediate in newly invaded sites. Soil available N, P and K concentrations in heavily invaded site were 2.4, 1.9 and 1.7 times higher than those in native plant soil, respectively. Soil pH decreased as A. artemisiifolia invasion intensity increased, and was lower in invaded sites（heavily invaded and newly invaded） than in native plant sites. The soil microbial community structure was clearly separated in the three types of sites, and A. artemisiifolia invasion increased anaerobe, sulfate-reducing bacteria and actinomycete abundance. Soil biota of invaded sites inhibits growth of co-occurring plants（Galinsoga parvifloraCav., Medicago sativa L. and Setaria plicata（Lam.） T. Cooke.） compared to soil biota from un-invaded sites, but facilitates A. artemisiifolia growth and competition with co-occurring plants. A. artemisiifolia biomass was 50-130% greater when competing with three co-occurring plants, compared to single-species competition only（invasion by A. artemisiifolia alone）, in heavily invaded soil. Results of the present study indicated that A. artemisiifolia invasion alters the soil microbial community in a way that favors itself while inhibiting native plant species, with measurable effects on performance of co-occurring plants.

Effects of NO_(2) on Inflorescence Length,Pollen/Seed Amount and Phenolic Metabolites of Common Ragweed(Ambrosia artemisiifolia L.)

Ambrosia artemisiifolia L. (common ragweed) is an annual ruderal plant that is native to Northern America but nowadays is also spreading across Europe, and its pollen is known to be highly allergenic. Air pollution, e.g. NOx and climate change may affect the plant growth, pollen production and duration of the entire pollen season. In this study, ragweed plants were grown over an entire vegetation period under 40 ppb NO2/clean air (control) and 80 ppb NO2 (treatment). The inflorescence length was not affected by this air pollutant. However, the pollen amount increased, while the seed production decreased in both populations upon elevated NO2 concentrations. Regarding phenolic metabolites elevated NO2 had no effect on the amount of total phenolic metabolites, while individual metabolites showed significant changes.

豚草(Ambrosia artemisiifolia)不同器官与不同发育期中过氧化物酶同工酶分析

本文用凝胶电泳法测定了豚草根、茎、叶不同器官过氧化物酶同工酶酶谱,按其酶带相对迁移率(R_m),可分为11条酶带.豚草植株过氧化物酶同工酶与其他植物一样,有明显的器官特异性和阶段发育特异性.结果表明豚草茎叶中过氧化物酶酶谱在开花前后有明显的变化:(1)开花期较开花前酶带明显地增多;(2)开花期在主茎或叶片中,都会出现一条颜色较浅的,该器官花期特有的酶带;(3)豚草株体内一条主酶带(E 带)在开花期明显变浅.上述过氧化物酶同工酶的三种变化,为判断豚草植株体内开花前后生理生化变化提供了一种生化指标.

豚草(Ambrosia artemisiifolia L.)中化学成分及其生物活性的研究进展

豚草初提物具有较好的杀虫、杀螺、抑茵和化感等活性,已从豚草中分离鉴定的化学成分有几十种,主要包括萜类、酚酸类、聚乙炔类和甾醇类等四类,其中萜类化合物最多。本文对从豚草中提取的化合物及其活性进行了比较详细的叙述,为今后合理利用豚草资源提供一定依据。

外来入侵物种三裂叶豚草(Ambrosia trifida L.)及其风险分析

外来入侵物种严重威胁着农业生产、生态安全及人类健康,已成为世界各国广泛关注和研究的热点。本文对外来杂草三裂叶豚草(Ambrosia trifidaL.)的起源和分布、生物生态学特性、经济和生态影响及其控制管理措施等进行了系统综述。根据生物生态学特性、潜在风险及管理控制的难度等指标,初步建立了外来杂草的风险评估体系。应用该体系对三裂叶豚草进行了风险评估,得出其风险值为83,属高度危险的检疫性有害生物。

植物挥发性单萜经土壤载体的化感作用--以三裂叶豚草(Ambrosia trifida L．)为例

植物释放的挥发性单萜在生态系统中起着重要的作用,这些单萜不仅能以空气为载体对其他植物显示直接的化感作用,而且也能以土壤为载体进行间接的化感作用。通过对三裂叶豚草挥发物对植物种子萌发和土壤微生物种群影响及其化学成分的鉴定研究,验证了以单萜类物质为主的三裂叶豚草挥发物可以经土壤载体对其他植物及土壤微生物显示化感效应。还对植物挥发物化学成分鉴定的GC(气相色谱)和GC-MS(气相色谱-质谱联用)方法存在的一些误区进行了澄清,这将有助于对生态系统中植物挥发物化感作用的研究和认识。

新疆外来入侵杂草豚草属LAMP快速检测技术的建立

【目的】开发外来入侵生物三裂叶豚草和豚草不同生育期、不同部位的环介导等温扩增(loop-mediated isothermal amplification,LAMP)技术,以达到田间快速、准确和高效识别的目的。【方法】以SYBR Green Ⅰ为指示剂,分别针对三裂叶豚草和豚草不同发育阶段(幼苗期、生长期、种子期)开展LAMP技术开发。【结果】特异性验证结果显示,所检测杂草的LAMP产物均呈阳性(产生白色沉淀),而与其对照的其他2种杂草的LAMP产物均为阴性(无白色沉淀)。灵敏度检测结果显示,该体系的DNA最低检测限为10^(-10) ng·μL-1,比常规聚合酶链式反应灵敏度高。【结论】本研究建立的LAMP检测体系能有效应用于三裂叶豚草和豚草样本的快速检测,为其快速、高效识别提供技术支撑。

吉林省豚草瘦果形态及微结构特征

【目的】研究吉林省不同地区豚草瘦果形态及微结构特征,为豚草的识别及防控提供参考。【方法】采集吉林省吉林市磨盘山、吉林市龙潭山、桦甸市、蛟河市、长春市、四平市、公主岭市、通化市、白山市、白城市、松原市和乾安县12个地区不同豚草种群的瘦果进行扫描电镜观察、描述和拍照,分析豚草瘦果表型性状与地理-气候因子的相关性,并对瘦果形态及微结构特征进行聚类分析。【结果】豚草果皮纹饰有条状纹饰、网状纹饰和穴状纹饰;瘦果的喙长度随年均降水量增加而增加、随纬度升高而减少;果形系数随经度升高及年均降水量的增加而增加。根据形态和微结构性状聚类分析结果,将豚草瘦果分为3类(Ⅰ、Ⅱ、Ⅲ)。其中,Ⅰ类瘦果果皮纹饰网状、中果形、短喙类,种源主要来自蛟河市、通化市、公主岭市、松原市和乾安县;Ⅱ类瘦果果皮纹饰条状、小果形、中长喙类,种源主要来自吉林市磨盘山、吉林市龙潭山、桦甸市、长春市和四平市;Ⅲ类瘦果果皮纹饰穴状、大果形、长喙类,种源主要来自白山市和白城市。【结论】吉林省豚草瘦果形态及微结构存在差异,低纬度、高降水量有利于豚草瘦果生长发育。

豚草入侵新疆伊犁河谷的时空分布格局及扩散途径

【目的】豚草是世界范围内广泛入侵的植物,对入侵地经济发展、人体健康和生态安全产生严重危害。研究分析其入侵扩散媒介、切断其扩散来源对有效防控意义重大。【方法】通过对新疆伊犁河谷全境调查,分析豚草空间分布特征;采用空间代替时间的方法,结合地统计学,定量分析豚草不同入侵时间及生境的传播扩散特征,总结其扩散媒介和途径。【结果】豚草在伊犁河谷分布种群共计186个,其分布具有明显生境偏好,主要分布在道路两侧、河道和林下。道路两侧分布种群最多,占总分布种群点的32.34%,河道两侧分布面积最大,占伊犁河谷分布面积的69.01%。新源县是豚草的主要发生区,已形成4个严重入侵区和多个扩散源区。【结论】豚草早期扩散具有随机性,在不同生境内种群呈集中分布。不同生境中扩散媒介各有侧重,以农牧物资运输和牛羊携带为主。因此,道路和河道两侧是防控的重点,同时要加强对农牧产品调运和动物活动的监管,减少动物辅助扩散传播。研究为豚草在伊犁河谷的防控研究提供中烟基础数据。

除草剂对广聚萤叶甲(Ophraella communa)存活的影响

为筛选出对豚草天敌广聚萤叶甲低毒的除草剂,达到化学防治与生物防治的协同关系,研究了草甘膦异丙胺盐、百草枯、氟磺胺草醚、乳氟禾草灵和氯氟吡氧乙酸5种除草剂对广聚萤叶甲卵、幼虫、蛹和成虫存活的影响。结果表明,在常用剂量下,百草枯处理的广聚萤叶甲成虫存活率在16.9%以下,蛹存活率低于70.6%,但其对卵和幼虫的影响较小。中等剂量下,草甘膦异丙胺盐、氟磺胺草醚、乳氟禾草灵和氯氟吡氧乙酸处理的成虫存活率均在70%以上,幼虫存活率均高于90%,且对卵和蛹几乎无致死作用。说明百草枯对广聚萤叶甲的毒害作用较强,建议在豚草综合治理中慎用百草枯。

贵阳市三裂叶豚草秋冬季植株开花动态观察

为了解三裂叶豚草的秋冬季开花动态情况,采用查阅资料及野外观察的方法,分析其与三裂叶豚草在贵州成功越冬的关系。结果表明:晚至7月份发芽出土的三裂叶豚草的花期可以在秋冬季开花且可以完成整个生活史。植株较矮小的三裂叶豚草更易提前结束秋冬季花期;植株较高大的植株则更倾向花期延长,大大增加了其成功越冬的可能性。

Benefit of Adding Ammonium Sulfate or Additional Glyphosate to Glyphosate in Corn and Soybean

Nine field trials (4 in corn and 5 in soybean) were conducted over 2 years (2014 and 2015) to determine if there is greater benefit of adding ammonium sulfate (AMS) (2.5 L·haˉ1) or an equal dollar value of glyphosate (406 g·ae·haˉ1) to glyphosate applied at 450, 675 or 900 g·ae·haˉ1 for weed control in corn and soybean. Glyphosate applied at 450 g·ae·haˉ1 controlled velvetleaf 90% to 98%, common ragweed 80% - 97%, common lambsquarters 91% - 99%, Eastern black nightshade 83% - 100% and barnyardgrass 73% - 97% in corn and common ragweed 37% - 89%, common lambsquarters 39% - 98%, barnyardgrass 90% - 98% and green foxtail 91% - 98% in soybean. The addition of AMS to glyphosate applied at 450, 675 or 900 g·ae·haˉ1 provided little to no added benefit for the control of velvetleaf, common ragweed, common lambsquarters, Eastern black nightshade, barnyardgrass and green foxtail in corn and soybean. There was a greater benefit in weed control efficacy by simply adding and equal dollar value of glyphosate (406 g·ae·haˉ1) than AMS (2.5 L·haˉ1) to glyphosate. There was no difference in corn or soybean yield among the herbicide treatments evaluated. Based on these results, addition of AMS to glyphosate at rates evaluated had little benefit on weed control efficacy or yield of corn and soybean.

豚草杀虫抑菌活性成分的LC-MS分析

本研究采用LC-MS(液相色谱-质谱联用)技术对豚草中的生物活性成分进行了定性分析,结果表明:含有五种具有杀虫抑菌活性的化学成分,分别为绿原酸、豚草素、二氢豚草素、银胶菊酯和冠裸穗豚草素。

繁殖体压力对豚草(Ambrosia artemisiifolia)定殖和种群维持的影响

从北京门头沟收集入侵植物豚草(Ambrosia artemisiifolia)的种子,在北京顺义区休耕地上进行为期2年的田间实验。通过引入不同数量的豚草种子:5、10、20和40粒·m^(-2),研究不同繁殖体压力对入侵初期豚草出苗、定殖和种群维持的影响。结果表明:繁殖体压力大小对豚草成功定殖样方比例有显著影响,其中繁殖体压力达到20粒·m-2后所有样方均成功定殖且第二年种群继续扩大;种子引入第二年样方内豚草幼苗数和定殖植株数均显著高于第一年(P<0.05);第一年有1~3株豚草成功定殖的样方即可基本满足第二年豚草种群的维持,第二年成功出苗5~237株,定殖4~97株。以上结果表明,小批量豚草种子的传入即具有较大的入侵风险,且传入种子数量越多,风险越大;豚草在只有少数几株成功定殖的情况下就有极大可能产生足够多的种子以满足种群的维持和扩张。因此,在豚草的防控工作中,应加强对豚草种子的检疫,并且重视豚草新分布区零星植株的及时清除。

广西外来入侵植物豚草的分布调查

2019—2022年,对广西111个县(市、区)的豚草分布进行样带调查。结果表明,横州、兴宾、上林、武宣、象州、鹿寨、宾阳、灌阳和隆林9个县(市、区)有豚草发生;除了在兴宾区持续蔓延之外,横州市和上林县成为豚草的新增暴发热点,新热点的传播风险更大。装卸场是豚草发生率和归化率最高的生境,车辆传播和污染泥土传播是广西豚草扩散的主要渠道。环境的物种丰富度与豚草盖度呈负相关,但与豚草发生率和归化率均无显著关联。桂中平原周边的崇山峻岭对豚草传播起到隔离带作用。南部沿海地区的北海、钦州和防城港均未发现豚草,这种情况可能与冬季气候温和有关。

吉林省豚草种子微结构变异分析

为探究吉林省豚草种子的微结构变异,本研究从吉林省的12个市(县)不同豚草种群采集种子进行扫描电镜观察,对豚草种子表型性状与地理、气候因子进行相关性分析,对种子表型性状进行了聚类分析。结果表明,吉林省12个地区豚草种子的表皮纹饰均为条状,种子可分2类。第Ⅰ类为短喙、中小种形种子,包括四平市、白山市、吉林市龙潭山、蛟河市、松原市、吉林市磨盘山、通化市、公主岭市、乾安县、长春市和白城市种源;第Ⅱ类为长喙、大种形种子,仅包括桦甸市种源。12个地区豚草种子微结构存在变异,表型性状相同的豚草种子微结构存在差异,表型性状不同的豚草种子其纹饰类型也有相似之处。

The rhythmic expression of genes controlling flowering time in southern and northern populations of invasive Ambrosia artemisiifolia

Aims Flowering time has been suggested to be an important adaptive trait during the dispersal of invasive species,and identifying the molecu-lar mechanisms underlying flowering time may provide insight into the local adaptation during the process of invasion.Here,we con-ducted a preliminary exploration on the genetic basis of the differ-entiation of flowering time in Ambrosia artemisiifolia.Methods using relative real-time fluorescent quantitative polymerase chain reaction,we investigated the expression levels of eight flowering-related genes,including AP1,FT,SOC1,CRY2,FKF1,GI,CO2 and SPY,in leaves and flowers at different time points in individuals from northern beijing and southern Wuhan populations that exhibit significant differences in flowering times to identify any rhythmic changes in gene expression and their association with differential flowering times.Important Findings The differentiation of flowering time in the A.artemisiifolia popula-tions was closely associated with five genes involved in flowering pathways.The floral pathway integrators FT and SOC1 and floral meristem identity gene AP1 exhibited increased expression during flowering.The photoreceptor CRY2 in the light-dependent path-way and the SPY gene in the gibberellin pathway displayed specific expression patterns over time.in earlier-flowering beijing plants,CRY2 expression was lower and SPY expression was higher than in Wuhan plants.The expression patterns of these five genes sug-gest a molecular basis for the differentiation of flowering time in A.artemisiifolia.

Prevalence of sensitization to weed pollens of Humulus scandens,Artemisia vulgaris,and Ambrosia artemisiifolia in northern China

Objective:Weed pollens are common sources of allergens worldwide.The prevalence of weed pollen sensitization is not yet fully known in China.The purpose of this study was to investigate the prevalence of sensitization to weed allergens from Artemisia,Ambrosia,and Humulus in northern China.Methods:A total of 1144 subjects(aged from 5 to 68 years) visiting our clinic from June to October 2011 underwent intradermal testing using a panel of 25 allergen sources.Subjects with positive skin responses to any pollen were further tested for their serum concentrations of IgE antibodies against Artemisia vulgaris,Ambrosia artemisiifolia,and Humulus scandens,and against the purified allergens,Art v 1 and Amb a 1.Results:Of 1144 subjects,170 had positive intradermal reactions to pollen and 144 donated serum for IgE testing.The prevalence of positive intradermal responses to pollens of Artemisia sieversiana,Artemisia annua,A.artemisiifolia,and H.scandens was 11.0%,10.2%,3.7%,and 6.6%,respectively.Among the intradermal positive subjects,the prevalence of specific IgE antigens to A.vulgaris was 58.3%,to A.artemisiifolia 14.7%,and to H.scandens 41.0%.The prevalence of specific IgE antigens to the allergen Art v 1 was 46.9%,and to Amb a 1 was 11.2%.The correlation between the presence of IgE antibodies specific to A.vulgaris and to the Art v 1 antigen was very high.Subjects with A.artemisiifolia specific IgE also had A.vulgaris specific IgE,but with relatively high levels of A.vulgaris IgE antibodies.There were no correlations between the presence of IgE antibodies to H.scandens and A.vulgaris or to H.scandens and A.artemisiifolia.Conclusions:The intradermal prevalence of weed pollen sensitization among allergic subjects in northern China is about 13.5%.Correlations of specific IgE antibodies suggest that pollen allergens from Artemisia and Humulus are independent sources for primary sensitization.

在中国大陆发现豚草条纹萤叶甲

20 0 4年 8～ 1 0月在浙江和江西省发现一种原产自北美洲的萤叶甲 :豚草条纹萤叶甲OphraellacommunaLeSage,其以豚草 (AmbrosiaartemisiifoliaL .)和三裂叶豚草 (AmbrosiatrifidaL .)为主要寄主。该虫在中国台湾和日本 (1 996)已有记录。