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 ...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.展开更多
【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...【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。展开更多
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...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.展开更多
During three years lasting studies on the territory of the city of Novi Sad, terrain studies of Ambrosia artemisiifolia L. distribution as well as mapping were performed on regulated and disordered green areas and on ...During three years lasting studies on the territory of the city of Novi Sad, terrain studies of Ambrosia artemisiifolia L. distribution as well as mapping were performed on regulated and disordered green areas and on arable areas. For mapping of ragweed distribution, partially modified method of Braun-Blanquet was used, and data processing was perfomed by specially designed program Ambrosia Spot Marker. Monitoring of this species was also done because of the occurrence of retrovegetation after mowing. During vegetation period, this allergenic weed species was controlled by multiple mowing, and rough ruderal sites outside settlements were treated by glyphosate at a rate of 1.2 kg ha^-1 -2.4 kg ha^-1. The study comprehended also monitoring of pollen concentrations in the air by Rotorod pollen sampler spore collector. A. artemisiifolia L. was established in 21 city zones on over 200 localities, on the banks of the river Danube, in Petrovaradin and Sremski Karlovci. Recommended mechanical measures such as mowing, drilling in the phase of germination, and chemical control measures, resulted in significant reduction ofA. artemisiifolia L. In the second half of the August 2009 the highest number of pollen grains was found in the amount of 783 pollen grains per m3 of air.展开更多
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·ha<sup>ˉ1</sup>) or an equa...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·ha<sup>ˉ1</sup>) or an equal dollar value of glyphosate (406 g·ae·ha<sup>ˉ1</sup>) to glyphosate applied at 450, 675 or 900 g·ae·ha<sup>ˉ1</sup> for weed control in corn and soybean. Glyphosate applied at 450 g·ae·ha<sup>ˉ1</sup> 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·ha<sup>ˉ1</sup> 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·ha<sup>ˉ1</sup>) than AMS (2.5 L·ha<sup>ˉ1</sup>) 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.展开更多
基金supported by the National Basic Research Program of China(2009CB119200)the National Natural Science Foundation of China(30871654)
文摘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.
文摘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.
文摘During three years lasting studies on the territory of the city of Novi Sad, terrain studies of Ambrosia artemisiifolia L. distribution as well as mapping were performed on regulated and disordered green areas and on arable areas. For mapping of ragweed distribution, partially modified method of Braun-Blanquet was used, and data processing was perfomed by specially designed program Ambrosia Spot Marker. Monitoring of this species was also done because of the occurrence of retrovegetation after mowing. During vegetation period, this allergenic weed species was controlled by multiple mowing, and rough ruderal sites outside settlements were treated by glyphosate at a rate of 1.2 kg ha^-1 -2.4 kg ha^-1. The study comprehended also monitoring of pollen concentrations in the air by Rotorod pollen sampler spore collector. A. artemisiifolia L. was established in 21 city zones on over 200 localities, on the banks of the river Danube, in Petrovaradin and Sremski Karlovci. Recommended mechanical measures such as mowing, drilling in the phase of germination, and chemical control measures, resulted in significant reduction ofA. artemisiifolia L. In the second half of the August 2009 the highest number of pollen grains was found in the amount of 783 pollen grains per m3 of air.
文摘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·ha<sup>ˉ1</sup>) or an equal dollar value of glyphosate (406 g·ae·ha<sup>ˉ1</sup>) to glyphosate applied at 450, 675 or 900 g·ae·ha<sup>ˉ1</sup> for weed control in corn and soybean. Glyphosate applied at 450 g·ae·ha<sup>ˉ1</sup> 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·ha<sup>ˉ1</sup> 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·ha<sup>ˉ1</sup>) than AMS (2.5 L·ha<sup>ˉ1</sup>) 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.
