In this study, Artemisia biennis was seeded in a greenhouse and raised to an average plant height of 100 cm. Aboveground plant portions were harvested and partitioned into leaves and stems, and dried;while roots were ...In this study, Artemisia biennis was seeded in a greenhouse and raised to an average plant height of 100 cm. Aboveground plant portions were harvested and partitioned into leaves and stems, and dried;while roots were either removed from some soil (soil – roots) or left in soil (soil + roots). Greenhouse studies were conducted to evaluate the allelopathic potential of A. biennis leaves, roots, and stems;and soil – roots, and soil + roots on Solanum melanocerasum plant height and fresh weight plant–1. When 5 g of root and stem biomass were added to soil, S. melanocerasum plant height and fresh weight plant–1 was reduced by 75 and 88%, respectively. In contrast, 5 g of leaf biomass caused an increase in S. melanocerasum plant height and fresh weight plant–1 by 35% and 43%, respectively;whereas, 20 g of leaf biomass depressed both variables by 50% and 65%, also respectively. Plant height was more suppressed when S. melanocerasum grew in soil – roots as opposed to soil + roots, whereas fresh weight plant–1 was similar between soil treatments. S. melanocerasum plant height was reduced by 70 and 55% when grown in soil – roots and soil + roots, respectively. In contrast, S. melanocerasum fresh weight plant–1 was reduced by 76% in both soil treatments. The reduction in S. melanocerasum plant attributes in this study is indicative of the allelopathic potential of A. biennis. Furthermore, A. biennis allelopathy is differenttially expressed among plant parts, primarily in roots. This may explain how A. biennis is capable of dominating a habitat once it becomes established. The presence of extractable compounds with herbicidal activity could increase the potential usefulness of A. biennis.展开更多
<p style="text-align:justify;"> <span><i><span style="font-family:""><span style="font-family:Verdana;">Citrus </span><span style="font-fa...<p style="text-align:justify;"> <span><i><span style="font-family:""><span style="font-family:Verdana;">Citrus </span><span style="font-family:Verdana;">tristeza</span><span style="font-family:Verdana;"> virus</span></span></i></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> (CTV) outbreaks have been reported in the main citrus growing region of Mexico in the past four years. Recently, in eastern Mexico (the major citrus-growing region in the country), severe CTV isolates have been detected. However, the molecular identity of </span><span style="font-family:Verdana;">observed</span><span style="font-family:Verdana;"> isolates remains unestablished. This research was undertaken to elucidate the molecular characterization of CTV populations spreading in this region and to compare it with </span><span style="font-family:Verdana;">phylogeny</span><span style="font-family:Verdana;"> of existing isolates. Genotyping of 32 collected isolates was performed using reverse-transcription polymerase chain reaction (RT-PCR) with sequence analysis of the coat protein (CP) gene, putatively associated with pathogenicity. This protein is a 25 kDa major capsid protein, which forms a long virion body coating 95% of the particle length. </span><span style="font-family:Verdana;">A comparative</span><span style="font-family:Verdana;"> sequence </span><span style="font-family:Verdana;">analys</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">is</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> was performed using CTV sequences from different geographical origins already published and deposited in the GenBank databases. Phylogenetic analysis showed that the degree of sequence divergence among isolates correlated with their pathogenicity. Based on the sequencing results, the collected isolates were categorizedn as mild or severe phylogenetic clusters, each being genetically distinct. The severe group was associated </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">with</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> either </span><span style="font-family:Verdana;">a</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">like</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> or with a T36-like genotype. The latter group matched with the quick decline and stem pitting drastic symptoms observed in the field. This study identified the presence of severe CTV isolates related to the T36-like genotype and to the cause of quick decline and stem pitting in sweet orange propagated on sour orange rootstock. Knowledge derived from these analyses could serve to design management strategies for this disease and to understand the cur</span><span style="font-family:Verdana;">rent epidemic outbreak in scenarios where the most efficient vector is present.</span></span></span></span><span></span><span style="font-family:""></span> </p>展开更多
This article is the 15th contribution in the Fungal Diversity Notes series,wherein 115 taxa from three phyla,nine classes,28 orders,48 families,and 64 genera are treated.Fungal taxa described and illustrated in the pr...This article is the 15th contribution in the Fungal Diversity Notes series,wherein 115 taxa from three phyla,nine classes,28 orders,48 families,and 64 genera are treated.Fungal taxa described and illustrated in the present study include a new family,five new genera,61 new species,five new combinations,one synonym,one new variety and 31 records on new hosts or new geographical distributions.Ageratinicolaceae fam.nov.is introduced and accommodated in Pleosporales.The new genera introduced in this study are Ageratinicola,Kevinia,Pseudomultiseptospora(Parabambusicolaceae),Marasmiellomycena,and Vizzinia(Porotheleaceae).Newly described species are Abrothallus altoandinus,Ageratinicola kunmingensis,Allocryptovalsa aceris,Allophoma yuccae,Apiospora cannae,A.elliptica,A.pallidesporae,Boeremia wisteriae,Calycina papaeana,Clypeo-coccum lichenostigmoides,Coniochaeta riskali-shoyakubovii,Cryphonectria kunmingensis,Diaporthe angustiapiculata,D.campylandrae,D.longipapillata,Diatrypella guangdongense,Dothiorella franceschinii,Endocalyx phoenicis,Epicoc-cum terminosporum,Fulvifomes karaiensis,F.pannaensis,Ganoderma ghatensis,Hysterobrevium baoshanense,Inocybe avellaneorosea,I.lucida,Jahnula oblonga,Kevinia lignicola,Kirschsteiniothelia guangdongensis,Laboulbenia caprina,L.clavulata,L.cobiae,L.cosmodisci,L.nilotica,L.omalii,L.robusta,L.similis,L.stigmatophora,Laccaria rubriporus,Lasiodiplodia morindae,Lyophyllum agnijum,Marasmiellomycena pseudoomphaliiformis,Melomastia beihaiensis,Nemania guangdongensis,Nigrograna thailandica,Nigrospora ficuum,Oxydothis chinensis,O.yunnanensis,Petriella thailandica,Phaeoacremonium chinensis,Phialocephala chinensis,Phytophthora debattistii,Polyplosphaeria nigrospora,Pronectria loweniae,Seriascoma acutispora,Setoseptoria bambusae,Stictis anomianthi,Tarzetta tibetensis,Tarzetta urceolata,Tetraploa obpyriformis,Trichoglossum beninense,and Tricoderma pyrrosiae.We provide an emendation for Urnula ailaoshanensis Agaricus duplocingulatoides var.brevisporus introduced as a new variety based on morphology and phylogeny.展开更多
Biochar is known to ameliorate soil fertility and increase crop yield;however,information regarding its effects on soil chemical and biological properties remains limited.The experiment was conducted to study the shor...Biochar is known to ameliorate soil fertility and increase crop yield;however,information regarding its effects on soil chemical and biological properties remains limited.The experiment was conducted to study the short-term impacts of dif-ferent types of biochar on soil C fractions,enzyme activities,and microbial community structure at depositional and eroded landscape positions at different sampling times[before planting,after planting,and after harvesting of soybean(Glycine max L.)].Three biochar materials,produced from C-optimized gasification of corn(maize,Zea mays L.)stover(CS),pon-derosa pine(Pinus ponderosa Lawson and C.Lawson)wood residue(PW),and switchgrass(Panicum virgatum L.)(SG),and dairy manure(DM)and mixture of dairy manure and pinewood biochar(DMP),were applied at a rate of 10 Mg ha^(−1) to depositional and eroded landscape positions.Data showed that the application of DMP and sole application of DM treat-ments significantly increased the labile C fractions at the depositional and eroded landscapes.The addition of DM and DMP increased the activities ofβ-glucosidase and urease enzymes,and those are involved in C and nitrogen cycling at depositional and eroded landscape positions.There were no significant differences between different biochar materials.However,there was an increase in soil microbial community structure in the DM and DMP treatments at both the landscape positions.In conclusion,our study revealed that DMP and sole application of DM influenced the soil labile C pool,enzyme activities,and microbial community structure at both the landscape positions for different sampling times.展开更多
文摘In this study, Artemisia biennis was seeded in a greenhouse and raised to an average plant height of 100 cm. Aboveground plant portions were harvested and partitioned into leaves and stems, and dried;while roots were either removed from some soil (soil – roots) or left in soil (soil + roots). Greenhouse studies were conducted to evaluate the allelopathic potential of A. biennis leaves, roots, and stems;and soil – roots, and soil + roots on Solanum melanocerasum plant height and fresh weight plant–1. When 5 g of root and stem biomass were added to soil, S. melanocerasum plant height and fresh weight plant–1 was reduced by 75 and 88%, respectively. In contrast, 5 g of leaf biomass caused an increase in S. melanocerasum plant height and fresh weight plant–1 by 35% and 43%, respectively;whereas, 20 g of leaf biomass depressed both variables by 50% and 65%, also respectively. Plant height was more suppressed when S. melanocerasum grew in soil – roots as opposed to soil + roots, whereas fresh weight plant–1 was similar between soil treatments. S. melanocerasum plant height was reduced by 70 and 55% when grown in soil – roots and soil + roots, respectively. In contrast, S. melanocerasum fresh weight plant–1 was reduced by 76% in both soil treatments. The reduction in S. melanocerasum plant attributes in this study is indicative of the allelopathic potential of A. biennis. Furthermore, A. biennis allelopathy is differenttially expressed among plant parts, primarily in roots. This may explain how A. biennis is capable of dominating a habitat once it becomes established. The presence of extractable compounds with herbicidal activity could increase the potential usefulness of A. biennis.
文摘<p style="text-align:justify;"> <span><i><span style="font-family:""><span style="font-family:Verdana;">Citrus </span><span style="font-family:Verdana;">tristeza</span><span style="font-family:Verdana;"> virus</span></span></i></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> (CTV) outbreaks have been reported in the main citrus growing region of Mexico in the past four years. Recently, in eastern Mexico (the major citrus-growing region in the country), severe CTV isolates have been detected. However, the molecular identity of </span><span style="font-family:Verdana;">observed</span><span style="font-family:Verdana;"> isolates remains unestablished. This research was undertaken to elucidate the molecular characterization of CTV populations spreading in this region and to compare it with </span><span style="font-family:Verdana;">phylogeny</span><span style="font-family:Verdana;"> of existing isolates. Genotyping of 32 collected isolates was performed using reverse-transcription polymerase chain reaction (RT-PCR) with sequence analysis of the coat protein (CP) gene, putatively associated with pathogenicity. This protein is a 25 kDa major capsid protein, which forms a long virion body coating 95% of the particle length. </span><span style="font-family:Verdana;">A comparative</span><span style="font-family:Verdana;"> sequence </span><span style="font-family:Verdana;">analys</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">is</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> was performed using CTV sequences from different geographical origins already published and deposited in the GenBank databases. Phylogenetic analysis showed that the degree of sequence divergence among isolates correlated with their pathogenicity. Based on the sequencing results, the collected isolates were categorizedn as mild or severe phylogenetic clusters, each being genetically distinct. The severe group was associated </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">with</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> either </span><span style="font-family:Verdana;">a</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">like</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> or with a T36-like genotype. The latter group matched with the quick decline and stem pitting drastic symptoms observed in the field. This study identified the presence of severe CTV isolates related to the T36-like genotype and to the cause of quick decline and stem pitting in sweet orange propagated on sour orange rootstock. Knowledge derived from these analyses could serve to design management strategies for this disease and to understand the cur</span><span style="font-family:Verdana;">rent epidemic outbreak in scenarios where the most efficient vector is present.</span></span></span></span><span></span><span style="font-family:""></span> </p>
文摘This article is the 15th contribution in the Fungal Diversity Notes series,wherein 115 taxa from three phyla,nine classes,28 orders,48 families,and 64 genera are treated.Fungal taxa described and illustrated in the present study include a new family,five new genera,61 new species,five new combinations,one synonym,one new variety and 31 records on new hosts or new geographical distributions.Ageratinicolaceae fam.nov.is introduced and accommodated in Pleosporales.The new genera introduced in this study are Ageratinicola,Kevinia,Pseudomultiseptospora(Parabambusicolaceae),Marasmiellomycena,and Vizzinia(Porotheleaceae).Newly described species are Abrothallus altoandinus,Ageratinicola kunmingensis,Allocryptovalsa aceris,Allophoma yuccae,Apiospora cannae,A.elliptica,A.pallidesporae,Boeremia wisteriae,Calycina papaeana,Clypeo-coccum lichenostigmoides,Coniochaeta riskali-shoyakubovii,Cryphonectria kunmingensis,Diaporthe angustiapiculata,D.campylandrae,D.longipapillata,Diatrypella guangdongense,Dothiorella franceschinii,Endocalyx phoenicis,Epicoc-cum terminosporum,Fulvifomes karaiensis,F.pannaensis,Ganoderma ghatensis,Hysterobrevium baoshanense,Inocybe avellaneorosea,I.lucida,Jahnula oblonga,Kevinia lignicola,Kirschsteiniothelia guangdongensis,Laboulbenia caprina,L.clavulata,L.cobiae,L.cosmodisci,L.nilotica,L.omalii,L.robusta,L.similis,L.stigmatophora,Laccaria rubriporus,Lasiodiplodia morindae,Lyophyllum agnijum,Marasmiellomycena pseudoomphaliiformis,Melomastia beihaiensis,Nemania guangdongensis,Nigrograna thailandica,Nigrospora ficuum,Oxydothis chinensis,O.yunnanensis,Petriella thailandica,Phaeoacremonium chinensis,Phialocephala chinensis,Phytophthora debattistii,Polyplosphaeria nigrospora,Pronectria loweniae,Seriascoma acutispora,Setoseptoria bambusae,Stictis anomianthi,Tarzetta tibetensis,Tarzetta urceolata,Tetraploa obpyriformis,Trichoglossum beninense,and Tricoderma pyrrosiae.We provide an emendation for Urnula ailaoshanensis Agaricus duplocingulatoides var.brevisporus introduced as a new variety based on morphology and phylogeny.
基金Financial support for this work was provided by the United States Department of Agriculture,Natural Resources Conservation Service(Grant no.G17AC00337)。
文摘Biochar is known to ameliorate soil fertility and increase crop yield;however,information regarding its effects on soil chemical and biological properties remains limited.The experiment was conducted to study the short-term impacts of dif-ferent types of biochar on soil C fractions,enzyme activities,and microbial community structure at depositional and eroded landscape positions at different sampling times[before planting,after planting,and after harvesting of soybean(Glycine max L.)].Three biochar materials,produced from C-optimized gasification of corn(maize,Zea mays L.)stover(CS),pon-derosa pine(Pinus ponderosa Lawson and C.Lawson)wood residue(PW),and switchgrass(Panicum virgatum L.)(SG),and dairy manure(DM)and mixture of dairy manure and pinewood biochar(DMP),were applied at a rate of 10 Mg ha^(−1) to depositional and eroded landscape positions.Data showed that the application of DMP and sole application of DM treat-ments significantly increased the labile C fractions at the depositional and eroded landscapes.The addition of DM and DMP increased the activities ofβ-glucosidase and urease enzymes,and those are involved in C and nitrogen cycling at depositional and eroded landscape positions.There were no significant differences between different biochar materials.However,there was an increase in soil microbial community structure in the DM and DMP treatments at both the landscape positions.In conclusion,our study revealed that DMP and sole application of DM influenced the soil labile C pool,enzyme activities,and microbial community structure at both the landscape positions for different sampling times.