Phosphorus budgets in Everglades wetland ecosystems: the effects of hydrology and nutrient enrichment

The Florida Everglades is a naturally oligotrophic hydroscape that has experienced large changes in ecosystem structure and function as the result of increased anthropogenic phosphorus (P) loading and hydrologic changes. We present whole-ecosystem models of P cycling for Everglades wetlands with differing hydrology and P enrichment with the goal of synthesizing existing information into ecosystem P budgets. Budgets were developed for deeper water oligotrophic wet prairie/slough (‘Slough’), shallower water oligotrophic Cladium jamaicense (‘Cladium’), partially enriched C. jamaicense/Typha spp. mixture (‘Cladium/Typha’), and enriched Typha spp. (‘Typha’) marshes. The majority of ecosystem P was stored in the soil in all four ecosystem types, with the flocculent detrital organic matter (floc) layer at the bottom of the water column storing the next largest proportion of ecosystem P pools. However, most P cycling involved ecosystem components in the water column (periphyton, floc, and consumers) in deeper water, oligotrophic Slough marsh. Fluxes of P associated with macrophytes were more important in the shallower water, oligotrophic Cladium marsh. The two oligotrophic ecosystem types had similar total ecosystem P stocks and cycling rates, and low rates of P cycling associated with soils. Phosphorus flux rates cannot be estimated for ecosystem components residing in the water column in Cladium/Typha or Typha marshes due to insufficient data. Enrichment caused a large increase in the importance of macrophytes to P cycling in Everglades wetlands. The flux of P from soil to the water column, via roots to live aboveground tissues to macrophyte detritus, increased from 0.03 and 0.2 g P m⁻² yr⁻¹ in oligotrophic Slough and Cladium marsh, respectively, to 1.1 g P m⁻² yr⁻¹ in partially enriched Cladium/Typha, and 1.6 g P m⁻² yr⁻¹ in enriched Typha marsh. This macrophyte translocation P flux represents a large source of internal eutrophication to surface waters in P-enriched areas of the Everglades.     

隧蜂属(膜翅目,隧蜂科)相关类元名称的变动及隧蜂属的分类研究现状

扼要回顾了隧蜂科隧蜂属的分类变革,汇总了隧蜂属相关类元名称的变动情况,重新对隧蜂属下了定义,最后,根据最新研究结果,对全世界目前隧蜂属各亚属所含种的数量作了统计,给出了隧蜂属分亚属检索表.根据作者的研究结果,对中国隧蜂属的分类作了扼要的介绍.     

Marshland vegetation of the class <Emphasis Type="Italic">Phagmito-Magnocaricetea</Emphasis> in Croatia

The marshland vegetation of the class Phragmito-Magnocaricetea in Croatia is presented in a single place for the first time. All the available relevés from the literature have been assembled and supplemented with the results of field research. Thirty-three communities have been established, shown in a synoptic table drawn up on the basis of 486 relevés. The communities are understood according to the traditional syntaxonomic system based on the dominant or diagnostic species. For the purposes of comparison, the marshland vegetation is classified using numerical methods as well. The results obtained show that most clusters correspond to specific associations, but do not confirm the division into vegetation alliances and orders. The marshland communities with the most relevés in the dataset, and that therefore can be considered the most widespread in Croatia, are: Phragmitetum australis, Caricetum gracilis, and Galio palustris-Caricetum ripariae. The marshland vegetation is also analysed from the standpoint of nature conservation. In the dataset studied, 59 taxa from the Red Book of Vascular Flora of Croatia are identified as threatened, the 15 most endangered marshland communities are separated, and 10 neophytes and one neophyte association are registered. The diversity of marshland vegetation, and of the associated plant species, is considerably higher in inland Croatia than along the Adriatic coast, which is probably a result of the geological bedrock, climate and, in some places, halophile conditions.     

Structure of a new ribitol teichoic acid-like O-polysaccharide of a serologically separate Proteus vulgaris strain, TG 276-1, classified into a new Proteus serogroup O53

An unusual ribitol teichoic acid-like O-polysaccharide was isolated by mild acid degradation of the lipopolysaccharide from a previously non-classified Proteus vulgaris strain TG 276-1. Structural studies using chemical analyses and 2D (1)H and (13)C NMR spectroscopy showed that the polysaccharide is a zwitterionic polymer with a repeating unit containing 2-acetamido-4-amino-2,4,6-trideoxy-D-galactose (D-FucNAc4N) and two D-ribitol phosphate (D-Rib-ol-5-P) residues and having the following structure:[formula: see text] where the non-glycosylated ribitol residue is randomly mono-O-acetylated. Based on the unique O-polysaccharide structure and the finding that the strain studied is serologically separate among Proteus bacteria, we propose to classify P. vulgaris strain TG 276-1 into a new Proteus serogroup, O53.     

The closest relatives of cacti: insights from phylogenetic analyses of chloroplast and mitochondrial sequences with special emphasis on relationships in the tribe Anacampseroteae

Recent molecular and morphological systematic investigations revealed that the cacti are most closely related to Anacampseroteae, Portulaca and Talinum of the family Portulacaceae (ACPT clade of suborder Portulacineae). A combined analysis of ndhF, matK, and nad1 sequence data from the chloroplast and the mitochondrial genomes indicates that the tribe Anacampseroteae is the sister group of the family Cactaceae. This clade, together with Portulaca, is well characterized by the presence of axillary hairs or scales. Relationships within Anacampseroteae are characterized by a grade of five species of Grahamia s.l. from North and South America, and Grahamia australiana is found to be sister to the genera Anacampseros and Avonia. A comparison of vegetative characteristics indicates an evolutionary transition from woody subshrubs to dwarf perennial and highly succulent herbs during the diversification of Anacampseroteae. Available evidence from the present investigation as well as from previously published studies suggests that a revised classification of Portulacineae on the basis of inferred phylogenetic relationships might consist of a superfamily that includes Cactaceae and the three genera Anacampseros s.l. (including Avonia and Grahamia s.l.), Portulaca, and Talinum (including Talinella), either referred to three monogeneric families or to a paraphyletic family Portulacaceae*.     

应用AFLP标记对江西省猕猴桃种质资源的鉴别及其分类意义

 对江西省猕猴桃种质资源进行扩增片段长度多态性(AFLP)标记来鉴定分析.首先从64对引物筛选出4对引物,对31份种质材料的DNA进行检测,得到190个扩增基因位点,其中多态性位点179个,多态性比例为94.2%,对31份种质材料的区分率达到100%.然后,对扩增结果进行UPGMA聚类分析,谱系图显示,31份种质材料之间的相似系数在0.50～0.85之间,表明猕猴桃种质之间遗传关系相对来说不是很近.在相似系数0.56的水平上,可以将31份种质大致分为4个类群：净果组和斑果组为一类群;糙毛组为一类群;星毛组为一类群;中华猕猴桃和美味猕猴桃为一类群.从树状图中看,原为中华猕猴桃的一个变种的“赣猕5号”,现与中华猕猴桃并列,有对其作进一步分类方面深入研究的必要.本研究从分子角度鉴定分析了江西省猕猴桃种质资源及其遗传关系,其结果在很大程度上与传统分类是一致的,同时也为江西省猕猴桃种质资源分类学研究提供了新的证据.     

不同天气条件下青头潜鸭越冬期行为的响应模式

2018年11—12月在河南民权国家湿地公园,采用定点观察法、扫描取样法对越冬青头潜鸭在不同天气条件下的行为响应模式进行研究。结果表明: 在晴天,静息、飞行、运动是青头潜鸭越冬期的优势行为(65.5%),觅食、修整是次要行为(31.9%);行为节律表现为上午觅食、中午静息、下午觅食修整;飞行通常发生在觅食高峰前,运动行为多与其他行为相伴,其时间分配与觅食呈正响应,与静息呈负响应。相较于晴天,阴雨天青头潜鸭增加了对静息和觅食的时间分配,静息、觅食和运动为阴雨天的主要行为(76.5%),修整、飞行为次要行为(20.3%);觅食和静息的高峰时段后移,傍晚时达到高峰,飞行和修整时间显著减少。与晴天相比,雾霭天青头潜鸭静息、觅食、运动和修整的时间分配增加,飞行行为减少;觅食高峰后移至中午和下午,静息高峰后移至下午;静息、运动和觅食为雾霭天的优势行为(70.6%),修整和飞行为次要行为(27.5%)。研究表明,不同天气条件下,民权湿地公园青头潜鸭的越冬期行为在时间分配、行为节律、优势行为方面存在一定的响应;阴雨天和雾霭天青头潜鸭会分配更多的静息和觅食时间,并通过增加能量摄入和减少耗能行为应对恶劣天气。     

青藏高原植物群落样方数据集

为便于了解青藏高原植被特殊物种组成、群落特征及分布格局, 该文利用2018-2021年在青藏高原不同区域内调查的338个样地、共758个样方的数据, 分析了高原植物群落的物种组成、区系特征和植被分类, 整合形成青藏高原植物群落样方数据集。结果表明: 青藏高原高寒和温性植物群落758个样方中, 共有植物65科279属837种; 其中, 物种数最多的5个科依次是菊科(134种)、禾本科(88种)、豆科(75种)、蔷薇科(43种)和莎草科(40种), 物种数最多的5个属依次是蒿属(Artemisia, 29种)、马先蒿属(Pedicularis, 27种)、风毛菊属(Saussurea, 25种)、黄耆属(Astragalus, 23种)和早熟禾属(Poa, 23种)。植物区系主要由温带(145属)和世界广布(36属)的成分所组成。物种的生长型以草本(83.51%)和灌木(10.87%)为主, 草本和木本的生活型分别以多年生草本(88.23%)和落叶灌木(83.67%)为主。338个样地可以划分为4个植被型组, 10个植被型, 20个植被亚型, 78个群系组和117个群系, 其中草原群系34个, 草甸群系33个, 荒漠群系33个, 灌丛群系14个和针叶林群系3个。该数据集覆盖青藏高原绝大部分高寒灌丛、高寒草原、高寒草甸、高寒荒漠、温性草原和温性荒漠植被区域, 可为研究高原植被特征和地带性分异规律, 气候变化和人类活动对高原植被的影响及其生态恢复提供坚实的数据基础, 同时为下一代中国植被图的更新提供参考。     

Genome-based taxonomic classification of the closest-to-Comamonadaceae group supports a new family Sphaerotilaceae fam. nov. and taxonomic revisions

Many genera closest to the family Comamonadaceae have not been classified into any family; moreover, some of them are not monophyletic groups beyond the genus level. To resolve the taxonomic uncertainty of the closest-to-Comamonadaceae (CTC) group, we performed 16S rRNA gene- and genome-based phylogenetic analyses combined with genome relatedness indices and phenotypic traits comparison. Phylogenies based on the 16S rRNA gene and genome sequences demonstrated that the CTC group formed a coherent and robust monophyletic lineage and was sister to the family Comamonadaceae, thereby proposing the CTC group as a novel family, Sphaerotilaceae fam. nov. The resolved genus- and species-level taxonomic relationships of this new family were then validated by the phylogenomic reconstruction and comparisons of genome relatedness indices including digital DNA-DNA hybridization and average nucleotide identity (ANI) as well as comprehensive phenotypic analysis for type strains. Finally, we reclassified all misidentified genera and species, resulting in 19 new combinations, and proposed Sphaerotilaceae-specific thresholds of ANI and average amino acid identity for genus delineation. Collectively, this study has established a sound taxonomic framework of the novel family Sphaerotilaceae and will help guide future taxonomic efforts and prevent the propagation of taxonomic errors.     

食用菌病毒的研究进展

病毒是引起食用菌发生病害的重要病原之一,由于其具有潜隐性、不易辨认的特点,因而难以被人们所察觉,一旦发病就难以控制。在食用菌研究领域中,食用菌病毒使食用菌产量严重下降,引起的病害越来越受人们的重视,逐步成为该领域的研究热点。因此,本文主要针对食用菌病毒的结构与分类、危害、传播方式、检测方法以及食用菌病毒的脱毒技术等方面进行了综述,并对其存在的问题和前景进行了展望。这为食用菌病毒的检测、脱毒和无毒菌种的生产提供了理论依据,并为食用菌病毒的深入研究提供参考。