Functional diversity in nematode communities across terrestrial ecosystems

Functional diversity can be defined as the distribution of trait values within a community. Hence, functional diversity can be an indicator of habitat filtering and a reliable environmental predictor of ecosystem functioning. However, there is a serious lack of studies that test how functional diversity indices change depending on the environmental conditions. The aim of this study is to provide such evidence by analyzing the distribution and variation of continuous body-mass values (i.e. functional diversity) and related shifts in body length and width in a nematode community.We used a large online dataset on nematode traits to analyze: (i) the distribution of body mass using three functional diversity indices, i.e. functional richness, functional divergence and functional evenness; (ii) the shifts in body-size traits (length and width); and (iii) the body-mass distributions of five trophic groups and of the entire nematode community.Managed grasslands exhibited the widest range of body-mass values while body-mass distribution in arable fields covered the greatest area in comparison to the other ecosystem types. The shift in body size revealed environmental filters that could not have been identified by the study of functional diversity indices per se. We found low values of functional evenness to be associated with high values of functional richness. We provide novel empirical evidence that body-mass distribution within a trophic group mirrors the effects of habitat filtering more than the distribution in the community as a whole. Hence, our trait-based approach, more than functional diversity itself, disclosed soil food-web structure and identified community responses.     

Effects of different components of diversity on productivity in artificial plant communities

In an experiment on artificial plant communities, the effects of three components of plant diversity—plant species diversity, plant functional group diversity and plant functional diversity—on community productivity and soil water content were compared. We found that simple regression analysis showed a positive diversity effect on ecosystem processes (productivity and soil water content). However, when three components of diversity were included in the multiple regression analyses, the results showed that functional group diversity and functional diversity had more important effects on productivity and resource use efficiency. These results suggested that, compared with species number, functional differences among species and the range of functional traits carried by plants are the basis of biodiversity effects on ecosystem functioning. These diversity effects of increasing functional group diversity or functional diversity were likely because species differing greatly in size, life form, phenology and capacity to capture and use resources efficiently in diverse communities realize complementary resource use in temporal, spatial, and biological ways.     

开垦对阿拉善荒漠啮齿动物群落功能多样性的影响

开垦会导致荒漠化的加剧,并对动物群落产生严重的影响。而功能多样性恰恰能体现环境或干扰胁迫导致的群落结构差异。但有关啮齿动物群落功能多样性的研究并不多见,为此,我们在2018至2020年的4月、7月和10月利用铗日法对开垦区和未开垦区的啮齿动物群落进行调查,选择并量化了与其营养、生活史、生理、形态及活动节律等相关的5个功能性状,以探讨开垦对啮齿动物群落组成的影响,以及性状组成和功能多样性变化。研究结果表明：(1)开垦区群落的丰富度指数、多样性指数和均匀度指数均低于未开垦区,开垦改变了啮齿动物群落性状组成;(2)阿拉善荒漠啮齿动物群落组成与蛰眠、繁殖周期和食性等功能性状显著相关;(3)开垦区春、秋季群落功能丰富度和功能均匀度高于未开垦区,各季节群落功能离散度显著高于未开垦区;而未开垦区夏季群落功能丰富度高于开垦区,秋季群落功能均匀度高于开垦区;(4)开垦区和未开垦区群落功能丰富度最高值均出现在夏季,二者在不同季节间差异较大;开垦区群落功能均匀度最高值出现在春季、功能离散度最高值出现在秋季,二者在季节间差异均较小;未开垦群落功能均匀度最高值出现在秋季、功能离散度最高值出现在夏季,二者在季节间差异均较大。上述结果说明,阿拉善荒漠区啮齿动物群落功能多样性变化与土地开垦和季节相关联,开垦会从啮齿动物群落的生态空间利用程度、资源利用、种间竞争及生态位等方面影响群落功能多样性。     

Functional diversity analysis helps to identify filters affecting community assembly after fen restoration by top-soil removal and hay transfer

Top-soil removal followed by species introduction through hay transfer has appeared as a method to restore drained fens. This method addresses abiotic constraints by restoring hydrology and nutrient status, and biotic constraints by removing an unwanted seed bank and counteracting dispersal-limitation. Restoration works by altering environmental filters. Knowledge about the restoration actions effect on functional traits is necessary to understand which types of species may establish. In this study we analyse which factors in top-soil removal followed by hay transfer influence selection and composition of functional traits. Top-soil removal followed by hay transfer from reference sites was conducted at two sites in the Całowanie fen, 33 km SE of Warsaw, Poland. Species and abundance data were recorded for three consecutive years. These data, combined with data on functional traits were used to analyse the effect of the restoration actions on four functional diversity-indices and the community weighted mean of functional traits. Our results reveal a strong habitat filter in the restoration site that follows an elevation gradient. At low elevation this filter selects low values of autochory and specific leaf area and high values of clonal lateral spread, Ellenberg moisture values, and dispersal through hydrochory. The transferred hay differs in trait characteristics compared to the reference site vegetation by having species of higher specific leaf area, lower Ellenberg moisture value and lower dispersal by autochory and hydrochory. The result presented here has three important implications for fen restoration. First, the difference in trait-characteristics between the transferred hay and the reference site it was harvested from limits the restoration potential. Second, since for several fen species important functional traits are filtered along an elevation-gradient, careful planning regarding depth of top-soil removal is needed. Finally the results illustrate how a functional analysis can be used to detect environmental filters acting during ecological restoration.     

Trap architecture in carnivorous Utricularia (Lentibulariaceae)

Within carnivorous plants, the bladderworts (Utricularia) possess the most complicated traps whose mechanisms are not yet completely understood. For the first time, a representative survey of different traps from both subgenera (Utricularia and Polypompholyx) is presented.

Based on scanning- and transmission electron microscopy, traps of 14 species of Utricularia (out of 215 species) representing 11 sections (out of 35 sections) and including all life forms (aquatic, epiphytic, and terrestrial) were investigated. Additionally, it was tested whether life forms correlate with trapping mechanisms. Most morphological and anatomical features of the traps vary considerably between the different life forms, e.g. position of trap and trap entrance as well as form and position of trap appendages. Morphological data support the basal position of subgenus Polypompholyx within the genus. Some characteristics of the traps of terrestrial Utricularia multifida (subgenus Polypompholyx) differ remarkably from traps of the other species, e.g. trap-door anatomy and trap walls. This might be an indication for a primordial (non-suction) trapping mechanism in the former species, similar to that of the eel-traps of the closely related genus Genlisea.     

Protein interaction networks in plants

Protein–protein interactions are fundamental to virtually every aspect of cellular functions. With the development of high-throughput technologies of both the yeast two-hybrid system and tandem mass spectrometry, genome-wide protein-linkage mapping has become a major objective in post-genomic research. While at least partial “interactome” networks of several model organisms are already available, in the plant field, progress in this respect is slow. However, even with comprehensive protein interaction data still missing, substantial recent advance in the graph-theoretical functional interpretation of complex network architectures might pave the way for novel approaches in plant research. This article reviews current progress and discussions in network biology. Emphasis is put on the question of what can be learned about protein functions and cellular processes by studying the topology of complex protein interaction networks and the evolutionary mechanisms underlying their development. Particularly the intermediate and local levels of network organization—the modules, motifs and cliques—are increasingly recognized as the operational units of biological functions. As demonstrated by some recent results from systematic analyses of plant protein families, protein interaction networks promise to be a valuable tool for a molecular understanding of functional specificities and for identifying novel regulatory components and pathways.     

Functional regularity: a neglected aspect of functional diversity

Functional diversity has been identified as a key to understanding ecosystem and community functioning. However, due to the lack of a sound definition its nature and measurement are still poorly understood. In the same way that species diversity can be split into species richness and species evenness, so functional diversity can be split into functional richness (i.e. the amount of functional trait/character/attribute space filled) and functional evenness (i.e. the evenness of abundance distribution in functional trait space). We propose a functional regularity index (FRO) as a measure of functional evenness for situations where species are represented only by a single functional trait value (e.g. mean, median or mode), and species abundances are known. This new index is based on the Bulla O index of species evenness. When dealing with functional types or categorical functional traits, the Bulla O or any other accepted species evenness index may be used directly to measure functional evenness. The advantage of FRO is that it supplies a measure of functional evenness for continuous trait data. The FRO index presented in this paper fulfils all the a priori criteria required. We demonstrate with two example datasets that a range of FRO values may be obtained for both plant and animal communities. Moreover, FRO was strongly related to ecosystem function as seen in photosynthetic biomass in plant communities, and was able to differentiate sampling stations in a lagoon based on the functional traits of fish. Thus, the FRO index is potentially a highly useful tool for measuring functional diversity in a variety of ecological situations.     

The functional importance of rare and dominant species in a Neotropical forest bird community

Bird communities in Tropical forests have high rate of rare species, but only recently some studies suggested their disproportional role for the overall functional diversity. We investigated data from bird communities monitored annually using point counts over ten years in Iguassu National Park, that is a large and protected area in the southern portion of the Atlantic Forest in Brazil. We aimed (1) to determine the rare and dominant species in the community based on their abundance over time; (2) to evaluate the impact of each class of rarity on the overall functional volume of the community; (3) to investigate the pattern of occupancy of the trait space filled by each dominance class, and (4) to assess the disparity in functional trait composition between classes of rarity. We defined dominant, intermediate, and rare species in communities using cluster analysis and data of relative abundance of species in five sections of 1-km in the forest interior. The number of clusters was defined in accordance with the silhouette criterion measures of cohesion and separation that range from −1 to 1, with values > 0.5 indicating high-quality clusters. Among total 138 bird species recorded, 107 were rare, 26 intermediates, and 5 dominants. Our data corroborate a functional disproportional importance of rare bird species in the community considering the functional space (FRic), but functional dispersion (FDis) was not significantly different between the rare and intermediate species. In fact, there is a large overlap of the functional volume occupied by rare in relation to dominant/intermediate species. The niche space occupied by rare species covers most of the space occupied by intermediate and dominant species. The low representativeness of functional turnover indicates that few functions are unique to the classes of higher dominance. Our data suggest the importance of rare bird species to the overall functional diversity but also highlights the potential use of dominants/intermediates species as indicators to select important forests areas for conservation, as certain forest fragments. Through these most abundant species it would be possible to assess which functions are heaviest in abundance, becoming core functions, in the context of each independent forest fragment.     

植物功能基因组学研究进展

植物功能基因组学是从整体水平研究基因的功能及表达规律的科学。对植物功能基因组学的研究将助于我们对基因功能的理解和对植物性状的定性改造和利用。本文简要介绍了植物功能基因组学的概念、研究方法和最新研究进展。     

Field observed relationships between biodiversity and ecosystem functioning during secondary succession in a tropical lowland rainforest

The relationship between biodiversity and ecosystem functioning (BEF) is one of the most concerned topics in ecology. However, most of the studies have been conducted in controlled experiments in grasslands, few observational field studies have been carried out in forests. In this paper, we report variations of species diversity, functional diversity and aboveground biomass (AGB) for woody plants (trees and shrubs) along a chronosequence of four successional stages (18-year-old fallow, 30-year-old fallow, 60-year-old fallow, and old-growth forest) in a tropical lowland rainforest recovered after shifting cultivation on Hainan Island, China. Fifty randomly selected sample plots of 20 m × 20 m were investigated in each of the four successional stages. Four functional traits (specific leaf area, wood density, maximum species height and leaf dry matter content) were measured for each woody plants species and the relationships between species/functional diversity and AGB during secondary succession were explored. The results showed that both plant diversity and AGB recovered gradually with the secondary succession. AGB was positively correlated with both species and functional diversity in each stage of succession. Consistent with many controlled experimental results in grasslands, our observational field study confirms that ecosystem functioning is closely related to biodiversity during secondary succession in species rich tropical forests.     

水稻功能基因组学研究策略

自80年代第一株可育转基因水稻问世以来,水稻转化研究进展迅速。已采用包括农杆茵介导等许多转化方法。随着水稻基因组测序计划的完成,以功能基因组学研究为代表的后基因组时代已经到来。丰富的信息资源将为水稻功能基因的发掘创造十分有利的条件。本文将对水稻功能基因组的研究进展及其方法等进行简要概括。     

药用植物功能基因

药用植物功能基因研究是药用植物基因研究中最活跃的领域。以药用植物功能基因在GenBank中注册的统计数据为基础 ,介绍了药用植物功能基因研究的最新进展。注册的功能基因涉及 32属 42种药用植物。统计数据包括 :自 1 992年至 2 0 0 3年 (前 9个月 )每年注册基因总数、基因注册数最多的 1 6种主要的药用植物以及在药用植物功能基因研究方面比较活跃的 1 4个国家。还重点报道了植物功能基因专利注册情况、黄酮类化合物与紫杉醇生物合成基因研究进展以及植物P45 0基因研究现状 ,对药用植物生物合成功能基因研究的发展趋势进行了探讨。     

cDNA微阵列技术在植物功能基因组学研究中的应用

cDNA微阵列 (cDNAMicroarrays)技术是近年发展起来的分子生物学研究新型工具 ,以分子杂交为基本原理 ,在检测植物基因表达水平、研究基因表达图谱、特异基因检测以及发现新基因和分离差异表达基因等方面有着独特的优势 ,已成为植物功能基因组学研究的重要手段。     

Differential gene expression during seed germination in barley (Hordeum vulgare L.)

A barley cDNA macroarray comprising 1,440 unique genes was used to analyze the spatial and temporal patterns of gene expression in embryo, scutellum and endosperm tissue during different stages of germination. Among the set of expressed genes, 69 displayed the highest mRNA level in endosperm tissue, 58 were up-regulated in both embryo and scutellum, 11 were specifically expressed in the embryo and 16 in scutellum tissue. Based on Blast X analyses, 70% of the differentially expressed genes could be assigned a putative function. One set of genes, expressed in both embryo and scutellum tissue, included functions in cell division, protein translation, nucleotide metabolism, carbohydrate metabolism and some transporters. The other set of genes expressed in endosperm encodes several metabolic pathways including carbohydrate and amino acid metabolism as well as protease inhibitors and storage proteins. As shown for a storage protein and a trypsin inhibitor, the endosperm of the germinating barley grain contains a considerable amount of residual mRNA which was produced during seed development and which is degraded during early stages of germination. Based on similar expression patterns in the endosperm tissue, we identified 29 genes which may undergo the same degradation process. Electronic Publication     

Bioactive Sulforaphane from in vitro Propagated Brassica Seedlings

Sulforaphane is a biologically active phytochemical found abundantly in Brassica species. Sulforaphane from eighteen samples of three‐day‐old in vitro seedlings from Brassicas, the Brassica oleracea and Brassica rapa varieties were analyzed by HPLC. San Martino, cavolfiore Alverda, cavolo verza riccio d'Asti and cavolfiore Minaret (4.57; 4.54; 4.53 and 4.53 [mg/g d.w], respectively) seedlings showed the highest level of sulforaphane. The presented data may be applicable to choose sulforaphane‐rich Brassica varieties for functional foods. A higher sulforaphane content in functional foods might offer health benefits or desirable physiological effects.