Allelopathic potential of <i>Artemisia biennis</i>(biennial wormwood)

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.

Severe <i>Citrus tristeza virus</i>Isolates from Eastern Mexico Are Related to the T36 Genotype Group

Citrus tristeza virus (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 observed isolates remains unestablished. This research was undertaken to elucidate the molecular characterization of CTV populations spreading in this region and to compare it with phylogeny 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. A comparative sequence analysis 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 with either a-like 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 current epidemic outbreak in scenarios where the most efficient vector is present.

Fungal diversity notes 1611-1716: taxonomic and phylogenetic contributions on fungal genera and species emphasis in south China

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.

Short-term impacts of biochar and manure application on soil labile carbon fractions,enzyme activity,and microbial community structure

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.

Appreciating African American Rhetoric Through the Lens of Afrocentricity

本文透过非洲中心主义这个视角来讨论美国黑人话语的丰富性。这种美国黑人话语主要体现在诺莫人(Nommo)这个首要概念上,以及该概念的对于理解非洲中心世界观极其关键的各种特质上。本文将从理论上考察非洲中心主义的修辞,并阐释非洲中心主义的理论/哲学层面以及非洲中心主义与欧洲中心主义在话语理论化方式上的差异。本文指出理解诺莫人(Nommo)这个植根于非洲哲学和本体论的核心概念对有效分析和深入理解美国黑人话语至关重要。

Hans-Georg Gadamer on Praxis and Hermeneutical Understanding

汉斯—乔治·伽达默尔,于2002年5月13日与世长辞,享年102岁。他整个职业生涯都致力于研究理解的本质和文本的意义。自1960年代以来,他的划时代巨著《真理与方法》影响巨大,他关于阐释学的思想引发了国际学界和跨学科研究的革命。这篇文章旨在解释伽达默尔关于实践的观点,澄明伽达默尔在哲学解释学意义上"理解"的观念。

Perspectives on Authentic Dialogue as a Viable Pathway to Global Citizenship

我们生活在一个与他者文化频繁交往的时代,当代全球化条件下的各个文化区域处于相互依存的关系之中。各区域的经济、环境、宗教及政治的问题并非是地方性的,而是某种与全球化相关的问题。为了更加有效地面对并解决这些问题,我们需要认真审视原先的"异"文化,需要拥有多元文化和全球文化观以克服文化差异,与他者文化展开合作。作者在此文中以三位重要的欧洲哲学家马丁·布伯、卡尔·雅斯贝尔斯、汉斯-格奥尔格·伽达默尔为中心,集中讨论"世界公民"的概念以及相关本质问题。作者认为,当代文化互识的有效性在于审视、理解并发展一种新的认同观,一种被称之为"世界公民"的全球身份认同意识。