Response of rocket salad germplasm (Eruca and Diplotaxis spp.) to major pathogens causing damping-off,wilting and leaf spot diseases

In the present study, 26 accessions of rocket salad belonging to four species (Eruca sativa Mill., Diplotaxis tenuifolia (L.) DC., Diplotaxis muralis (L.) DC. and Erucastrum spp.) were tested for resistance to damping-off, wilting and leaf spot disease causal agents. High susceptibility to Rhizoctonia solani was detected in all accessions while variability in rocket seedling susceptibility for Sclerotinia assays was observed. Susceptibility to wilting caused by the fungus Fusarium oxysporum f. sp. raphani was tested. E. sativa varieties exhibited a lower severity degree associated to yellowing-related symptoms compared to D. tenuifolia. Resistance assay using the bacterium Xanthomonas campestris pv. campestris was also performed. Five E. sativa varieties showed a disease incidence lower than 60% while all the D. tenuifolia accessions, showed a susceptibility of 100%. The present study represents a step towards the identification of genetic resources useful in breeding for the selections of novel resistant varieties.     

城市化对植物多样性影响的研究进展

本文综述了城市化对植物多样性影响的研究进展。随着全球特别是发展中国家城市化水平的提高, 城市化对生物多样性的影响逐渐引起了人们的重视。城市化造成了本土植物物种的丢失和外来物种的增加。在空间分布上, 城市化还常使城区本土植物多样性沿着远郊农区－城郊－城区梯度性下降; 但是由于引进大量外来物种, 总体植物多样性反而升高, 沿着远郊农区－城郊－城区梯度性升高。城市化对植物种类组成也有很大影响,优势种在远郊农区、城郊和城区呈现不同。城市化对植物多样性影响的机制主要有人为引入外来物种、小生境改变以及景观格局的变化三个方面。以下四个研究方向将越来越重要: (1) 不同区域、不同方法、不同学科的系统整合研究;(2) 城市化扩张与植物多样性变化过程的定位监测研究; (3) 本土植物多样性丢失以及性状改变的内在机制研究, 特别是外来物种与本地物种的相互作用过程和机制的研究; (4) 城市植物多样性保护研究。     

The little fire ant Wasmannia auropunctata: a new invasive species in the Middle East and its impact on the local arthropod fauna

The little fire ant, Wasmannia auropunctata, probably arrived in Israel in ca. 1998 and was identified in 2005; this is the first record of this species from open areas outside the tropics and subtropics. It survives harsher conditions than in its native habitats, with minimal annual temperatures as low as 6°C, and 5–12 consecutive rainless months (under 15 mm rainfall per month). It is now known from 26 localities in Israel, mostly in irrigated gardens. As in other regions where they have invaded, these ants pose a serious threat to local biodiversity. At high densities they displaced almost all the local ant species sampled, affecting population abundances, species richness, and community structure. W. auropunctata seems to have a detrimental effect also on other ground arthropods, judging from the observed decline in spider and beetle abundances. We show here that this tropical species can pose a critical threat to local arthropods at a wider range of climatic conditions than was previously known.     

Phylogenetic analyses of <Emphasis Type="Italic">Phragmites</Emphasis> spp. in southwest China identified two lineages and their hybrids

The species/lineage delimitation and possible hybridization/introgression are prerequisites in the management of invasive organism. Phragmites australis invaded diverse habitats and displaced the native lineages in North America as a consequence of the introduction from the Eurasia. Such species threatened the biodiversity safety of the invaded regions, in particular the biodiversity hot spots. Southwest (SW) China is a biodiversity hot spot with the occurrence of Phragmites species, both native and introduced. However, the genetic identity of Phragmites species in this biodiversity hot spot remains unclear, hampering effective ecological managements. In this study, we explored the phylogenetic lineages of Phragmites species in SW China. A total of 44 accessions sampled across SW China were analyzed using two chloroplast DNA (cpDNA) markers and amplified fragment length polymorphisms. Two genetic lineages were recovered, i.e., (1) the tropical lineage which primarily consisted of native Phragmites species represented by cpDNA haplotypes I, Q, and U in relatively low altitude and (2) the common lineage including native species at higher elevations in the Hengduan Mountains as well as artificially planted species represented by cpDNA haplotype P. The between-lineage hybridization was suggested for five analyzed accessions collected from either natural or artificial habitats. The putative hybrids might have originated from the maternal native tropical lineages and paternal introduced common lineage. Our results suggest the likelihood of introgressive hybridizations in SW China and thus provided implications for future research and ecological management.     

Genetic diversity and relationships among Canavalia ensiformis (L.) DC. Accessions as revealed by sequence-related amplified polymorphism markers

Canavalia ensiformis is an under-exploited legume that has been used as forage, green manure, and a cover crop. Thus far, studies of the C. ensiformis germplasm have focused on morphological traits, which cannot be used to distinguish all known accessions or to evaluate their genetic diversity precisely. In this study, sequence-related amplified polymorphism (SRAP) markers were used to assess the genetic diversity and relationships among 29 C. ensiformis accessions originating from 16 countries. In total, 274 clear bands were amplified and 144 of them (52.6%) were polymorphic. The polymorphism information content values (PIC) ranged from 0.10 to 0.43, with an average of 0.27. An analysis of molecular variance (AMOVA) revealed that the most significant variation (92.0% of the total) occurred among accessions; the remaining 8.0% was attributed to variation within accessions. A cluster analysis and principal coordinates (PCoA) analysis produced similar results, whereby the 29 C. ensiformis accessions were divided into 5 clusters, each of which was composed of different accessions with different phenotypic traits. This study provides the theoretical basis for future biodiversity studies and breeding programs.     

Morpho–physiological responses of Rocket (<Emphasis Type="Italic">Eruca sativa</Emphasis> L.) varieties to sodium sulfate (Na<Subscript>2</Subscript>SO<Subscript>4</Subscript>) stress: an experimental approach

Rocket (Eruca sativa L.) is a medicinal plant that belongs to the Brassicaceae family and was reported to be a tolerant plant under soil salinity as well as high genetic diversity among its varieties. Since morphological and physiological changes to sodium sulfate stress toward this plant have not been investigated yet, the present study was implemented to assess the response of rocket (Eruca sativa L.) varieties to sodium sulfate (Na2SO4) stress as well as the relationship among these traits. Two varieties of rocket plants, the Iranian and Italian ones, were subjected to four salinity (Na₂SO₄) treatments [0 (control), 15, 30 and 60 mM of Na₂SO₄ solution] and three growth stages (49, 65, and 74 days) in factorial experiment with completely randomized design and three replications were considered. Some morphologic traits such as grain yield were measured during the growth period. The results of the analysis of variances between the mentioned variables indicated a significant difference between the varieties in terms of K⁺, Na⁺, Na⁺/K⁺, leaf length, grain yield, organic and mineral matter. The results of correlation and regression of the amounts of K⁺ showed a linear relationship with the grain yield and its variations were not independent from the variations of grain yield. Eventually, it seems that the Italian variety was more tolerant and having better performance in comparison with the Iranian variety, in response to salt stress.     

Structural elucidation of 4-(cystein-S-yl)butyl glucosinolate from the leaves of Eruca sativa

The structurally unique glucosinolate (GSL), 4-(cystein-S-yl)butyl GSL, was identified in the leaves of hydroponically-grown rocket salad (Eruca sativa Mill.). Its electrospray ionization mass spectrometry (ESI-MS)/MS spectrum indicated that this unusual GSL had a molecular weight of 414 as a desulfo (DS)-GSL, and a molecular formula of C(14)H(25)N(2)O(8)S(2) based on its negative ion matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) spectrum. For further confirmation, the 4-(cystein-S-yl)butyl DS-GSL was prepared with authentic L-Ser and purified dimeric 4-mercaptobutyl DS-GSL, and its chemical structure then confirmed by ESI-MS/MS data. It is named "glucorucolamine" as a trivial name from its ammonia sensitivity. This unique GSL was found to the greatest extent when rocket salad was grown in a 100% NH4+-N nutrient solution. Despite it clearly seems to reduce the detoxification of excess NH4+ in the leaves of rocket salad, present knowledge about the unique GSL is still far from being sufficient.     

Distribution and inheritance of beta-amylase alleles in north European barley varieties

Allelic diversity and inheritance of polymorphic sites of the intron III-exon IV region of the seed specific beta-amylase gene Bmy1 were studied in a set of 55 barley accessions composed mainly of old Latvian and Scandinavian commercial varieties and three Hordeum spontaneum lines from Israel. A CAPS-marker was used for genotyping the C698 --> T polymorphism encoding alleles of beta-amylase with different thermostability. The genotype C698 which is diagnostic for a more thermostable isoform of the beta-amylase was detected in 13 of the investigated accessions. In most cases the origin of the C698 genotype could be traced back to the old Danish variety Binder in the pedigree. However, this genotype was lost in later varieties originating from Binder. A 6+1 bp deletion event in intron III of the beta-amylase gene was in all cases linked to the presence of the C698 mutation, while the repeat number of a microsatellite in intron III had no correlation to the presence of the C698 mutation. Sequence analysis revealed a number of haplotypes within exon IV that did not result in amino acid changes due to the degenerated genetic code.     

4-Methylthiobutyl isothiocyanate (Erucin) from rocket plant dichotomously affects the activity of human immunocompetent cells

Isothiocyanates (ITC) from the Brassicaceae plant family are regarded as promising for prevention and treatment of cancer. However, experimental settings consider their therapeutic action without taking into account the risk of unwanted effects on healthy tissues. In the present study we investigated the effects of Eruca sativa seed extract containing MTBITC (Erucin) and pure Erucin from rocket plant on healthy cells of the human immune system in vitro. Hereby, high doses of the plant extract as well as of Erucin inhibited cell viability of human lymphocytes via induction of apoptosis to comparable amounts. Non-toxic low concentrations of the plant extract and pure Erucin altered the expression of the interleukin (IL)-2 receptor but did not affect further T cell activation, proliferation and the release of the effector molecules interferon (IFN)-gamma and IL-2 of T-lymphocytes. However, the activity of NK-cells was significantly reduced by non-toxic concentrations of the plant extract and pure Erucin. These results indicate that the plant extract and pure Erucin interfere with the function of human T lymphocytes and decreases the activity of NK-cells in comparable concentrations. Long-term clinical studies with ITC-enriched plant extracts from Brassicaceae should take this into account.     

云南昆明市双哨乡双桥村户级植物资源多样性保护与利用

以位于昆明城市饮用水保护区的双桥自然村为调查点,采用参与性生物多样性评估(Participatory biodiversity appraisal,简称PBA)方法,在当地村民参与下随机调查了100户农户种植管理和利用的植物种和品种多样性.结果表明,100户农户共种植管理和保存着70个植物物种,共有150个大田栽培植物、庭园观赏和绿化等植物品种.其中大田栽培物种31个、105个品种,庭园观赏、绿化等物种39个、45个品种,有着丰富的植物资源多样性.大田植物如玉米(Zea mays L.)、马铃薯(Solanum tuberosum L.)、豌豆(Pisum sativam L.)、烟草(Nicotiana tabacum L.)、小麦(Triticum aestivum L.)、白菜(Brassica pekinesis Rupr.)和蚕豆(Vicia faha L.)等物种资源及其品种被广泛栽种和利用,而观赏和绿化植物种相对较少.户级水平间种植利用的植物资源数量和多样性存在明显差异,6%的农户栽种、管理和利用的植物种和品种的多样性和丰富程度高,因而对植物多样性保护有较大贡献.     

Impacts of Carpobrotus edulis (L.) N.E.Br. on the Germination,Establishment and Survival of Native Plants: A Clue for Assessing Its Competitive Strength

Does Carpobrotus edulis have an impact on native plants? How do C. edulis’ soil residual effects affect the maintenance of native populations? What is the extent of interspecific competition in its invasion process? In order to answer those questions, we established pure and mixed cultures of native species and C. edulis on soil collected from invaded and native areas of Mediterranean coastal dunes in the Iberian Peninsula. We examined the impact of the invader on the germination, growth and survival of seeds and adult plants of two native plant species (Malcolmia littorea (L.) R.Br, and Scabiosa atropurpurea L.) growing with ramets or seeds of C. edulis. Residual effects of C. edulis on soils affected the germination process and early growth of native plants in different ways, depending on plant species and density. Interspecific competition significantly reduced the germination and early growth of native plants but this result was soil, density, timing and plant species dependent. Also, at any density of adult individuals of C. edulis, established native adult plants were not competitive. Moreover, ramets of C. edulis had a lethal effect on native plants, which died in a short period of time. Even the presence of C. edulis seedlings prevents the recruitment of native species. In conclusion, C. edulis have strong negative impacts on the germination, growth and survival of the native species M. littorea and S. atropurpurea. These impacts were highly depended on the development stages of native and invasive plants. Our findings are crucial for new strategies of biodiversity conservation in coastal habitats.     

Employing DNA barcoding as taxonomy and conservation tools for fish species censuses at the southeastern Mediterranean,a hot-spot area for biological invasion

This study evaluates the utility of DNA barcoding (mitochondrial cytochrome oxidase subunit I; COI) as a biodiversity and conservation applied tool for identifying fish fauna from the southeastern Mediterranean (the continental coast of Israel), a hot-spot area for biological invasion, also with an eye to establish the foundation for follow-up studies that will use environmental DNA (eDNA) tracks of native and invasive species, and for the application of eDNA concepts and methodologies in nature conservation. We established a dataset of 280 DNA barcodes, representing 110 marine fish species (all identified by a taxonomist), belonging to 75 native and 35 Lessepsian migratory species that were tested within and against the BOLD system database. Most of the query sequences showed 98% matches with reference DNA barcodes in the BOLD system excluding two Trachurus species, three Dasyatis pastinaca and two Rhinobatos rhinobatos individuals. Relatively high intraspecific genetic distances were observed in two Elasmobranchii species (8.83%–18%), suggesting possible cryptic species. In contrast, relatively low interspecific genetic distances were found between two Actinopterygii species (1.54%). Gobiidae family members were observed as being the most scattered on the Bayesian tree. Out of the 110 fish species, 48 were taxonomically discordant with the BOLD BINs (4 at the family level, 15 at the genus level and 29 at the species level), 53 were concordant and 9 were singletons. Discordancy was noted for some Diplodus and Fistularia species during the BOLD BIN analysis. Apogon queketti, Champsodon nudivittis and Cheilodipterus novemstriatus were uploaded to the BOLD system for the first time. We elucidated 177 haplotypes, 122 for the native fish species and 55 for the Lessepsian species. The results will allow the evaluation of invasive species success and will help developing improved policies for the conservation of Mediterranean biodiversity.     

Woodland biodiversity, palaeo-human ecology and some implications for conservation management

This paper appraises the role of prehistoric human societies in modifying the natural woodland biodiversity of several regions throughout Scotland. It draws attention to the likelihood that, contrary to popular belief, biodiversity was enhanced by interactions between agricultural communities and woodlands. The possible purposefulness of such interactions is discussed. Mindful of the present concern to re-establish ‘native’ woodlands in many parts of northern Britain, we then review three approaches to the identification of native tree types in Scotland, and conclude that insufficient attention in reafforestation schemes is being paid to (a) the palaeoecological record as a record of native woodland or (b) the likely former high taxonomic diversity of woodlands. Both these failings will lead to the creation of new woodlands lacking in species diversity.     

Does restoration help the conservation of the threatened forest of Robinson Crusoe Island? The impact of forest gap attributes on endemic plant species richness and exotic invasions

Invasive plant species are major drivers of biodiversity losses, especially on islands which are prone to invasions and extinctions. In the “endemic montane forest” of Robinson Crusoe Island (Pacific Ocean, Chile) invasive exotic plant species threaten conservation efforts by establishing in gaps and outcompeting native tree species regeneration. We compared gap attributes and ground vegetation cover in three gap types: those dominated by native species (<5 % cover of invasive species), invaded gaps (>30 % cover by invasive species), and treated gaps (invasive species removed). We examined (a) which gap attributes favored native and exotic species, (b) the relationship between gap size and species richness, and (c) species responses to invasion and treatment. Gaps ranged in size from 46 to 777 m² caused mainly by uprooted and snapped trees. Multi response permutation procedures showed a different floristic composition between natural, invaded and treated gaps. The presence of Myrceugenia fernandeziana (native species) and Aristotelia chilensis (invasive species) as gap border trees was positively and negatively correlated with native species richness, respectively. New gaps had more native species than old gaps, and smaller gaps contained relatively more native species than larger ones. An increase in invasive species cover was related to a decline in native species cover and richness. 1–6 years after treatment gaps tended to recover their native floristic composition. Highly effective conservation management programs will concentrate on monitoring gap creation, early control of invasive species, and by treating smaller gaps first.     

Genetic,phytochemical and biochemical analyses as tools for biodiversity evaluation of wild accessions of Solanum commersonii

Genetic fingerprint profiles, the type and content of glycoalkaloids (GAs) and hemagglutination (HAG) activity against red cells were analysed in accessions of Solanum commersonii, collected from different locations in the south of Uruguay. Thirty-nine accessions from 21 geographically distinct areas were studied. Random Amplified Polymorphic DNA (RAPD) analysis revealed a high degree of genetic diversity among the accessions used in the study and effectively discriminated among all of the accessions analysed. There was a very high diversity in the type as well as the concentration of GAs in the samples. Strong HAG activity against rabbit red cells was detected in all the S. commersonii tuber extracts analysed. Such activity was specifically inhibited by N,N′-diacetylchitobiose and N,N′,N″-triacetylchitotriose. Differences in the levels of specific HAG activities were found in the different extracts, which might indicate different levels of the lectin specific for N-acetylglucosamine (Glc-NAc) and its oligomers, in the tubers. It is shown that the three different approaches used in this work successfully discriminate between the accessions of this species and thus, they constitute interesting tools to analyse biodiversity within one species. In addition, they allow selection of those accessions with potential to be used in crop programs.     

Effects of Invasive-Plant Management on Nitrogen-Removal Services in Freshwater Tidal Marshes

Establishing relationships between biodiversity and ecosystem function is an ongoing endeavor in contemporary ecosystem and community ecology, with important practical implications for conservation and the maintenance of ecosystem services. Removal of invasive plant species to conserve native diversity is a common management objective in many ecosystems, including wetlands. However, substantial changes in plant community composition have the potential to alter sediment characteristics and ecosystem services, including permanent removal of nitrogen from these systems via microbial denitrification. A balanced assessment of costs associated with keeping and removing invasive plants is needed to manage simultaneously for biodiversity and pollution targets. We monitored small-scale removals of Phragmites australis over four years to determine their effects on potential denitrification rates relative to three untreated Phragmites sites and adjacent sites dominated by native Typha angustifolia. Sediment ammonium increased following the removal of vegetation from treated sites, likely as a result of decreases in both plant uptake and nitrification. Denitrification potentials were lower in removal sites relative to untreated Phragmites sites, a pattern that persisted at least two years following removal as native plant species began to re-colonize treated sites. These results suggest the potential for a trade-off between invasive-plant management and nitrogen-removal services. A balanced assessment of costs associated with keeping versus removing invasive plants is needed to adequately manage simultaneously for biodiversity and pollution targets.     

New Caledonia: A Hot Spot for Valuable Chemodiversity Part 3: Santalales,Caryophyllales, and Asterids

The flora of New Caledonia encompasses more than 3000 plant species and an endemism of almost 80%. New Caledonia is even considered as one of the 34 ‘hot spots’ for biodiversity. Considering the current global loss of biodiversity and the fact that several drugs and pesticides become obsolete, there is an urgent need to increase sampling and research on new natural products. In this context, here, we reviewed the chemical knowledge available on New Caledonian native flora from economical perspectives. We expect that a better knowledge of the economic potential of plant chemistry will encourage the plantation of native plants for the development of a sustainable economy which will participate in the conservation of biodiversity. This review is divided into three parts, and the third part which is presented here summarizes the scientific literature related to the chemistry of endemic santalales, caryophyllales, and asterids. We show that the high rate of endemism is correlated with the originality of phytochemicals encountered in New Caledonian plants. A total of 176 original natural compounds have been identified from these plants, whereas many species have not been investigated so far. We also discuss the economic potential of plants and molecules with consideration of their medicinal and industrial perspectives. This review finally highlights several groups, such as Sapotaceae, that are unexplored in New Caledonia despite the high chemical interest in them. These plants are considered to have priority in future chemical investigations.     

Complete Mitochondrial Genome of Eruca sativa Mill. (Garden Rocket)

Eruca sativa (Cruciferae family) is an ancient crop of great economic and agronomic importance. Here, the complete mitochondrial genome of Eruca sativa was sequenced and annotated. The circular molecule is 247 696 bp long, with a G+C content of 45.07%, containing 33 protein-coding genes, three rRNA genes, and 18 tRNA genes. The Eruca sativa mitochondrial genome may be divided into six master circles and four subgenomic molecules via three pairwise large repeats, resulting in a more dynamic structure of the Eruca sativa mtDNA compared with other cruciferous mitotypes. Comparison with the Brassica napus MtDNA revealed that most of the genes with known function are conserved between these two mitotypes except for the ccmFN2 and rrn18 genes, and 27 point mutations were scattered in the 14 protein-coding genes. Evolutionary relationships analysis suggested that Eruca sativa is more closely related to the Brassica species and to Raphanus sativus than to Arabidopsis thaliana.     

怒江河谷入侵植物与乡土植物丰富度的分布格局与影响因子

外来物种入侵严重威胁着乡土植物多样性并削弱了生态系统服务功能。本文基于滇西北怒江河谷植被调查的样方数据, 从群落水平研究了乡土和入侵植物多样性的空间分布格局, 以及地形、气候、人类干扰等因子对两种格局的影响。本研究共记录到外来入侵植物26种, 隶属于13科21属; 乡土植物1,145种, 分属于158科628属。沿着怒江河谷, 入侵植物物种丰富度随纬度与海拔的增加而减少; 乡土物种丰富度则随纬度增加而增加, 并在海拔梯度上呈单峰格局。运用广义线性模型分析公路边缘效应(反映生境干扰)、气候、地形和土壤等环境因素对物种丰富度分布格局的影响。等级方差分离的结果显示, 公路两侧的生境干扰对入侵种和乡土种的丰富度格局均具有首要影响。在自然环境因子中, 降水量是入侵植物丰富度的主要限制因子, 而乡土物种丰富度则主要受到地形因子尤其是坡向的影响。结构方程模型的分析结果也表明, 乡土植物和入侵植物丰富度之间的负相关关系反映了二者对环境响应的差异。本文结果支持物种入侵的资源可利用性限制假说, 并强调了人类活动对生物多样性的负面影响; 乡土植物或已较好地适应了干旱河谷气候, 但并没有显示出对外来物种入侵的抵抗作用。     

Treatment by glyphosate-based herbicide allowed recovering native species after Oxalis pes-caprae L. invasion: indications from a Mediterranean island

Biological invasions represent a global threat to biodiversity. Particular attention should be devoted to the management of alien plants, focusing on the opportunity to obtain a rapid response to invasion and restoration of the invaded areas. In this study we aimed to evaluate five different methods for controlling Oxalis pes-caprae, a well-known invasive plant native to South Africa, also focusing on the restoration of the native flora. We set an experiment on the island of Montecristo (central Mediterranean). Treatment methods varied from chemical to low risk methods, including manual removal, covering with mulching sheets, and foliar spraying with acetic acid (30% solution) and two different concentrations of glyphosate (3 and 5% solutions, respectively). The total cover of O. pes-caprae and of other native plants was sampled before treatments, and then several times during the subsequent year; while the plant species composition was sampled in late winter (March 2015–2016) and late spring (May 2015–2016). The use of glyphosate was found to be the only efficient control method, leading to a significant decrease in O. pes-caprae cover as well as to a recovery in native species cover and richness. The effect of the other control methods was negligible.