Natural diversity of inflorescence architecture traces cryptic domestication genes in barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.)

Many-grained mutants occurring spontaneously among their less well-endowed field mates may have appeared to early farmers as fortunate twists of fate foreboding wealth and abundance. In domesticated barley, the number of kernel rows in spike can be tripled by recessive mutant alleles at the Six-rowed spike 1 (vrs1) locus that abolish the suppression of lateral spikelet fertility. In another barley row-type, so called intermedium-spike (int), lateral floret size is often intermediate between six-and two-rowed types. Phenotypic and sequence analyses of our intermedium-spike collection revealed that other genes can increase the size of florets and even stimulate occasional grain setting in lateral spikelets. Here, we show that a complete six-rowed phenotype occurs in a diverse panel of intermedium-spike barley carrying wildtype Vrs1 in the presence of the Int-c.a allele of the intermedium spike-c (int-c) gene, previously considered only as a modifier of lateral spikelet fertility. Int-c.a-type alleles had arisen before domestication and are associated with the enlargement of lateral florets in wild barley, suggesting that natural selection/evolution acts towards reduced lateral floret size. Since Int-c.a cannot overcome the suppression of lateral florets in the genomic background of wild barleys, we infer the existence of other gene loci, at which novel alleles or allelic combinations were selected for after domestication, to increase grain number of barley independently of Vrs1.     

First insight into genetic diversity and population structure of the Caucasian wild apple (<Emphasis Type="Italic">Malus orientalis</Emphasis> Uglitzk.) in the Hyrcanian forest (Iran) and its resistance to apple scab and powdery mildew

Investigating population genetic structure and diversity, and resistance to pathogens in crop wild relatives are key steps to assess appropriate conservation and breeding programs. The Caucasian wild apple (Malus orientalis Uglitzk.) is an emblematic fruit tree of the Hyrcanian forest and is supposed to be a contributor to the cultivated apple genome (Malus domestica Borkh. Yet, no study has investigated its population structure, diversity and susceptibility to the two main pathogens of apples, the apple scab (Venturia inaqualis) and the powdery mildew (Podosphaera leucotricha). Here, we investigated population genetic structure and diversity of M. orientalis in the Hyrcanian forest as a mean to identifying future targeted populations for apple conservation and breeding programs. We genotyped using multilocus microsatellite 100 M. orientalis trees sampled in 14 sites. These trees were also screened for presence/absence of six (Rvi6, Vr, Rvi4, Rvi15, Rvi5 and Rvi11) and three (Pl-1, Pl-w, Pl-d) resistance genes to the apple scab and the powdery mildew respectively. Our results showed significant but weak between-site genetic differentiation and isolation by distance pattern suggesting substantial historical gene flow for M. orientalis in this area. We also detected a West-Eastern genetic structure across the Hyrcanian forest with five main populations showing admixture. We also showed a high diversity of resistance genes to apple scab across sites; in contrast, we only found one resistance gene to powdery mildew. These results are a first glimpse to settle wild apple conservation programs in Iran and pinpoint Iranian wild apple populations as an untapped source for apple breeding.     

Genotyping of the <Emphasis Type="Italic">SiDREB2</Emphasis> gene in worldwide foxtail millet (<Emphasis Type="Italic">Setaria italica</Emphasis> (L.) P. Beauv.) genetic resources with special attention to Indian landraces

We genotyped Setaria italica Dehydration-responsive element-binding 2 (SiDREB2) gene, which had been reported to be associated with dehydration stress tolerance, in 588 accessions of foxtail millet from various parts of Eurasia and other regions by a dCAPS marker. Of these, 480 accessions were genotyped in ribosomal DNA (rDNA), polyphenol oxidase (PPO) gene and Heading date 1 (HD1) gene in our previous studies, and 108 accessions from India were newly used in this study and genotyped in these genes in addition to the SiDREB2 gene. We compared the geographical distribution of the SiDREB2 genotypes with that of these three genes. Accessions from countries in South Asia including India and Sri Lanka were the most variable in the SiDREB2 gene followed by Korean accessions and Japanese accessions, suggesting that Indian accessions and East Asian accessions are useful as genetic resources for dehydration stress tolerance. This study also showed that although Indian accessions are not so diverse in rDNA and in transposon display markers previously studied, they are diverse in adaptive genes such as SiDREB2, PPO and HD1 genes.     

Diversity of the composition and content of soluble carbohydrates in seeds of the genus <Emphasis Type="Italic">Vicia</Emphasis> (Leguminosae)

Low molecular weight carbohydrates of seeds of 10 species of Vicia, namely: V. angustifolia, V. articulata, V. cordata, V. ervilia, V. johannis, V. macrocarpa, V. monantha, V. narbonensis, V. pannonica and V. sativa were analyzed by the high resolution gas chromatography method. Seeds of the investigated species contain common (glucose, fructose, myo-inositol, sucrose, galactinol, di-galactosyl myo-inositol and raffinose family oligosaccharides—RFOs) and species-specific carbohydrates (d-pinitol and its α-d-galactosides—in V. articulata, V. monantha and V. pannonica or d-ononitol and its galactoside—in V. ervilia). Among the species containing in seeds RFOs as the main α-d-galactosides (V. angustifolia, V. cordata, V. johanensis, V. macrocarpa, V. narbonensis and V. sativa), an additional subgroup can be separated, which contains a set of unknown compounds (found in V. angustifolia, V. cordata and V. macrocarpa). Moreover, several other unidentified carbohydrate-containing compounds were detected exclusively in seeds of V. ervilia. The concentrations of total soluble carbohydrates (TSCs), including sugars, RFOs, cyclitols and galactosyl cyclitols and unknown compounds, in seeds differ significantly (P < 0.05) among the species. RFOs and sucrose are the main fractions in TSCs, with the exception of V. pannonica seeds, containing more galactosyl pinitols, and V. ervilia, in which unknown compounds account for 50% of TSCs. In V. ervilia RFOs occur at the lowest concentration (9.32 mg g^?1 seeds), and the concentration of DGMI (di-galactosyl myo-inositol) is comparable with that of RFOs, which is unusual among all the investigated Vicia species.     

Phylogenetic relationships within <Emphasis Type="Italic">Lactuca</Emphasis> L. (Asteraceae), including African species,based on chloroplast DNA sequence comparisons

Lettuce (Lactuca sativa L.) belongs to the genus Lactuca L. and is an important vegetable worldwide. Over the past decades, there have been many controversies about the phylogeny of Lactuca species due to their complex and diverse morphological characters and insufficient molecular sampling. In this study we provide the most extensive molecular phylogenetic reconstruction of Lactuca, including African wild species, using two chloroplast genes (ndhF and trnL-F). The sampling covers nearly 40 % of the total endemic African Lactuca species and 34 % of the total Lactuca species. DNA sequences from all the subfamilies of Asteraceae in Genebank and those generated from Lactuca herbarium samples were used to establish the affiliation of Lactuca within Asteracaeae. Based on the subfamily tree, we selected 33 ndhF sequences from 30 species and 79 trnL-F sequences from 48 species to infer relationships within the genus Lactuca using randomized axelerated maximum likelihood and Bayesian inference analyses. Biogeographical, chromosomal and morphological character states were reconstructed over the Bayesian tree topology. We conclude that Lactuca contains two distinct phylogenetic clades—the crop clade and the Pterocypsela clade. Other North American, Asian and widespread species either form smaller clades or mix with the Melanoseris species. The newly sampled African endemic species probably should be treated as a new genus.     

Molecular phylogenetics and systematics of Trigonella L. (Fabaceae) based on nuclear ribosomal ITS and chloroplast trnL intron sequences

The genus Trigonella includes the widely cultivated T. foenum-graecum and a number of other medicinal and aromatic plant species distributed around the Mediterranean region. Sectional delimitation of Trigonella species is still based on morphology and interspecific relationships within the genus are not yet sufficiently resolved. Phylogenetic relationships in 22 species representing 11 of the 12 sections recognized within the genus Trigonella were analyzed using nuclear ITS and plastid trnL-F DNA sequences. Within nuclear ITS region, ITS-II was found to evolve faster compared to ITS-I. Maximal phylogenetic resolution and support was obtained in the combined analysis of the two selected regions. Trees resulting from maximum parsimony as well as Bayesian inference of combined data provided evidence for Trigonella being monophyletic with high support but did not agree with the traditional subgeneric division. Phylogenetic reconstructions indicated three major lineages supported by apomorphies in inflorescence and stipule. The phylogram supported the sectional delimitation of sections Cylindricae, Vérae, Samaroideae, Pectinatae, Erosae and Callicerates. There is strong support to combine monotypic sections Pectinatae and Erosae into one. However, species belonging to section Foenum-graecum and Falcatulae clustered in different subclades, contrary to their current classification. Inflorescence type appears to be a useful character with taxonomic potential for phenetic implications at subgeneric and sectional level within the genus. Moreover, some legume and seed characteristics, considered important in existing taxonomy, appear to have arisen more than once in Trigonella and are homoplastic.     

Agro-morphological traits of <Emphasis Type="Italic">Cicer reticulatum</Emphasis> Ladizinsky in comparison to <Emphasis Type="Italic">C. echinospermum</Emphasis> P.H. Davis in terms of potential to improve cultivated chickpea (<Emphasis Type="Italic">C. arietinum</Emphasis> L.)

Germplasm collections of C. reticulatum and C. echinospermum are limited, while both species face threats from over-grazing and habitat change in their natural environments. Recently many new accessions of C. reticulatum and C. echinospermum were collected in east and south-east Anatolia (Turkey) but they have not yet been evaluated for agro-morphological traits. Therefore, the current study investigated agro-morphological traits of new germplasm sources of C. reticulatum and C. echinospermum and evaluated resistance to biotic and abiotic stresses for chickpea improvement. The most attractive agro-morphological traits were canopy width, number of stems and pods per plant and biological yield. The most productive accessions of C. reticulatum and C. echinospermum had 712 and 625 pods per plant, respectively. Two distinct seed, flower and leaf shapes were found in accessions of C. echinospermum. Path analyses indicated that biological yield and harvest index had the most direct influence on seed yield in both species. Factor analyses showed that high seed yield in C. reticulatum depended on high biological yield and number of pods per plant, whereas high seed yield in C. echinospermum depended on harvest index. It was concluded that most accessions of C. reticulatum and C. echinospermum were not only resistant to some biotic and abiotic stresses but also had hidden alleles that could produce transgressive segregation in crosses to cultivated material.     

Morphological and genetic analysis of a cleistogamous mutant in rapeseed (<Emphasis Type="Italic">Brassica napus</Emphasis> L.)

Cleistogamy, the trait of non-opening flowers, is considered to be beneficial as it reduces the threat of genetic contamination and gene flow from genetically modified varieties into other crops or native species. A cleistogamous mutant Zhong9-Clg obtained in the rapeseed cultivar Zhongshuang 9 population (Brassica napus L.) treated by ethylmethanesulfonate were investigated. Mutation had pronounced effect on petal and sepal epidermal cells resulting in the inhibition or delay of petal development, forming folded petals which ultimately resulted in cleistogamous flowers. Genetic investigation revealed that this trait was monogenic and the allele for cleistogamy was dominant. Most of the eight agronomic traits tested, including seed yield per plant, were not significantly different between the mutant and wild type plants. Fertility of the cleistogamous mutant Zhong9-Clg was not significantly affected by mutation. Our research findings will lay the foundation for the development of the cleistogamous varieties that could be used in controlling the gene flow in rapeseed in combination with other means of containment strategies.     

The triparental triploid onion <Emphasis Type="Italic">Allium</Emphasis> × <Emphasis Type="Italic">cornutum</Emphasis> Clementi ex Visiani, 1842, possesses a sterile S-type of cytoplasm

Triploid onion, Allium × cornutum Clementi ex Visiani, 1842 (2n = 3x = 24), a vegetatively reproduced garden crop, possess a complex triparental genome organization with three putative parental species, A. cepa L., A. pskemense B. Fedtsch., and A. roylei Stearn. Two of its most studied clones are the Croatian ‘Ljutika’ and the Indian ‘Pran’, which are genetically highly similar. Earlier studies have shown that ‘Pran’ possesses some molecular markers in the chloroplast DNA (cpDNA) identical to those of the unique male-sterile (S) cytoplasm, used for onion breeding. To find out whether ‘Ljutika’ also possesses a S-type of cytoplasm, we analyzed several cpDNA and mitochondrial (mtDNA) molecular markers. The PCR amplification and RFLP analysis of the chloroplast genes accD, atpF, petB and the mitochondrial gene cob, as well as the sequence analysis of the chloroplast matK and atpB-rbcL regions showed that ‘Ljutika’ possesses the male-sterile S-type of cytoplasm. The phylogenetic analysis of the matK and atpB-rbcL sequences of A. × cornutum, its parental species and other Allium species of the section Cepa showed that none of the analyzed species had the identical type of cpDNA as A. × cornutum. Results also suggested that A. pskemense can be excluded as a donor of the S-cytoplasm and a female parent, whereas cpDNA of A. roylei, although not identical to S-cytoplasm, possessed many polymorphisms of S-type. Fluorescent in situ hybridization, using fluorescently labelled parental genomic DNAs as probes in combination with fluorescently labelled 5S and 35S rDNAs enabled simultaneous visualization of the three genomes during meiosis and confirmed their homeologus intergenomic pairing.     

Litter decomposition in peatlands is promoted by mixed plants

Purpose

The carbon sink function of peatlands is primarily driven by a higher production than decomposition of the litter Sphagnum mosses. The observed increase of vascular plants in peatlands could alter the decomposition rate and the carbon (C) cycle through a litter mixing effect, which is still poorly studied. Here, we examine the litter mixing effect of a peat moss (Sphagnum fallax) and two vascular plants (Pinus uncinata and Eriophorum vaginatum) in the field and laboratory-based experiment.

Materials and methods

During the laboratory incubation, mass loss, CO₂ production, and dissolved organic carbon concentration were periodically monitored during 51 days. The collected data were then processed in a C dynamics model. The calculated enzymatic activity was correlated to the measured β-glucosidase activity in the litter. In the field experiment, mass loss and CO₂ production from litter bags were annually measured for 3 years.

Results and discussion

Both laboratory and field experiments clearly show that the litter mixture, i.e., Sphagnum-Pinus-Eriophorum, had a synergistic effect on decomposition by enhancing the mass loss. Such enhanced mass loss increased the water extractable C and CO₂ production in the litter mixture during the laboratory experiment. The synergistic effect was mainly controlled by the Sphagnum-Eriophorum mixture that significantly enhanced both mass loss and CO₂ production. Although the β-glucosidase activity is often considered as a major driver of decomposition, mixing the litters did not cause any increase of the activity of this exo-enzyme in the laboratory experiment suggesting that other enzymes can play an important role in the observed effect.

Conclusions

Mixing litters of graminoid and Sphagnum species led to a synergistic effect on litter decomposition. In a context of vegetation dynamics in response to environmental change, such a mixing effect could alter the C dynamics at a larger scale. Identifying the key mechanisms responsible for the synergistic effect on litter decomposition, with a specific focus on the enzymatic activities, is crucial to better predict the capacity of peatlands to act as C sinks.

     

Potentialities of Six Plant Species on Phytoremediation Attempts of Fuel Oil-Contaminated Soils

A field experiment investigating the phytoremediation potential of six plant species—Goosegrass (Eleusine indica), Bermuda grass (Cynodon dactylon), Sessile joyweed (Alternanthera sessilis), Benghal dayflower (Commelina benghalensis), Lovanga (Cleome ciliata), and Chinese violet (Asystasia gangetica)—on soil contaminated with fuel oil (82.5 ml/kg of soil) have been conducted from March to August 2016. The experiments consider three modalities—Tn: unpolluted planted soils, To: unplanted polluted soils, and Tp: polluted planted soil—randomized arranged. Only three (E. indica, C. dactylon, and A. sessilis) of the six species survived while the others died 1 month after the beginning of experimentations. The relative growth indexes showed a strong similarity between the growth parameters of E. indica and C. dactylon, each on polluted and control soils, unlike A. sessilis. Total petroleum hydrocarbons (TPHs) removal efficiency were 82.56, 80.69, and 77% on soil planted with E. indica, C. dactylon, and A. sessilis, respectively; and 57.25% on non-planted soil. According to the bioconcentration and translocation factors, E. indica and A. sessilis are involved on rhizodegradation and phytoextraction of hydrocarbons whereas C. dactylon is only involved into rhizodegradation. Overall, E. indica and C. dactylon out-yielded A. sessilis in the phytoremediation capacity of fuel oil-contaminated soils.     

Predicting soil loss in central and south Italy with a single USLE-MM model

Purpose

The USLE-MM estimates event normalized plot soil loss, A_e,N, by an erosivity term given by the runoff coefficient, Q_R, times the single-storm erosion index, EI₃₀, raised to an exponent b₁?>?1. This modeling scheme is based on an expected power relationship, with an exponent greater than one, between event sediment concentration, C_e, and the EI₃₀/P_e (P_e = rainfall depth) term. In this investigation, carried out at the three experimental sites of Bagnara, Masse, and Sparacia, in Italy; the soundness of the USLE-MM scheme was tested.

Materials and methods

A total of 1192 (A_e,N, Q_REI₃₀) data pairs were used to parameterize the model both locally and considering all sites simultaneously. The performances of the fitted models were established by considering all erosive events and also by distinguishing between events of different severity.

Results and discussion

The b₁ exponent varied widely among the three sites (1.05–1.44) but using a common exponent (1.18) for these sites was possible. The A_e,N prediction accuracy increased in the passage from the smallest erosion events (A_e,N?≤?1 Mg ha^?1, median error =?3.35) to the largest ones (A_e,N?>?10 Mg ha^?1, median error =?1.72). The Q_REI₃₀ term was found to be usable to predict both A_e,N and the expected maximum uncertainty of this prediction. Soil erodibility was found to be mainly controlled by the largest erosion events.

Conclusions

Development of a single USLE-MM model appears possible. Sampling other sites is advisable to develop a single USLE-MM model for a general use.

     

Genetic diversity of dihydrochalcone content in <Emphasis Type="Italic">Malus</Emphasis> germplasm

Dihydrochalcones, beneficial phenolic compounds, are abundant in Malus Mill. species, particularly in vegetative tissues and seeds. Phloridzin (phloretin 2′-O-glucoside) is the primary dihydrochalcone in most Malus species including cultivated apple, Malus?×?domestica Borkh. A few species contain sieboldin (3-hydroxyphloretin 4′-O-glucoside) or trilobatin (phloretin 4′-O-glucoside) in place of phloridzin, and interspecific hybrids may contain combinations of phloridzin, sieboldin, and trilobatin. Proposed health benefits of phloridzin include anti-cancer, antioxidant, and anti-diabetic properties, suggesting the potential to breed apples for nutritional improvement. Sieboldin and trilobatin are being investigated for nutritional value and unique chemical properties. Although some of the biosynthetic steps of dihydrochalcones are known, little is known about the extent of variation within Malus germplasm. This research explores the genetic diversity of leaf dihydrochalcone content and composition in Malus germplasm. Dihydrochalcone content was measured using high performance liquid chromatography (HPLC) from leaf samples of 377 accessions, representing 50 species and interspecific hybrids from the USDA-Agricultural Research Service (ARS) National Plant Germplasm System Malus collection. Within the accessions sampled, 284 accessions contained phloridzin as the primary dihydrochalcone, one had only trilobatin, two had phloridzin and trilobatin, 36 had sieboldin and trilobatin, and 54 had all three. Leaf phloridzin content ranged from 17.3 to 113.7 mg/g with a heritability of 0.76 across all accessions. Beyond the potential of dihydrochalcones for breeding purposes, dihydrochalcone composition may be indicative of hybridization or species misclassification.     

Effects of vermicompost amendment as a basal fertilizer on soil properties and cucumber yield and quality under continuous cropping conditions in a greenhouse

Purpose

We examined the effects of vermicompost application as a basal fertilizer on the properties of a sandy loam soil used for growing cucumbers under continuous cropping conditions when compared to inorganic or organic fertilizers.

Materials and methods

A commercial cucumber (Cucumis sativus L.) variety was grown on sandy loam soil under four soil amendment conditions: inorganic compound fertilizer (750 kg/ha,), replacement of 150 kg/ha of inorganic compound fertilizer with 3000 kg/ha of organic fertilizer or vermicompost, and untreated control. Experiments were conducted in a greenhouse for 4 years, and continuous planting resulted in seven cucumber crops. The yield and quality of cucumber fruits, basic physical and chemical properties of soil, soil nutrient characteristics, and the soil fungal community structure were measured and evaluated.

Results and discussion

Continuous cucumber cropping decreased soil pH and increased electrical conductivity. However, application of vermicompost significantly improved several soil characteristics and induced a significant change in the rhizosphere soil fungal community compared to the other treatments. Notably, the vermicompost amendments resulted in an increase in the relative abundance of Ascomycota, Chytridiomycota, Sordariomycetes, Eurotiomycetes, and Saccharomycetes, and a decrease in Glomeromycota, Zygomycota, Dothideomycetes, Agaricomycetes, and Incertae sedis. Compared to the organic fertilizer treatment, vermicompost amendment increased the relative abundance of beneficial fungi and decreased those of pathogenic fungi. Cucumber fruit yield decreased yearly under continuous cropping conditions, but both inorganic and organic fertilizer amendments increased yields. Vermicompost amendment maintained higher fruit yield and quality under continuous cropping conditions.

Conclusions

Continuous cropping decreased cucumber yield in a greenhouse, but basic fertilizer amendment reduced this decline. Moreover, basal fertilizer amendment decreased beneficial and pathogenic fungi, and the use of vermicompost amendment in the basic fertilizer had a positive effect on the health of the soil fungal community.

     

Polymorphism of <Emphasis Type="Italic">Got2</Emphasis> DNA sequences sheds light on <Emphasis Type="Italic">Aegilops tauschii</Emphasis> Coss. intraspecies divergence and origin of <Emphasis Type="Italic">Triticum aestivum</Emphasis> L.

DNA sequences of nuclear gene Got2 was studied in 60 accessions of Aegilops tauschii, 29 of subsp. tauschii and 31 of subsp. strangulata. It was found that Got2 allozyme polymorphism in Ae. tauschii is due to a single, unique, mutation which led to replacement of glutamic acid by isoleucine in residue 256 of the enzyme molecule, encoded by Got2. As revealed by Got2 DNA sequences variation, initially in its history Ae. tauschii was presented by subsp. strangulata, and among phylogenetic lineages of subsp. strangulata, the lineage “t-9¹s” (TauL3) is the most ancient, a relict one. Subspecies tauschii is relatively “young”. Initially it was presented by the lineage marked by combination of allozyme alleles Got2 ¹⁰⁵ and Acph1 ¹⁰⁰. In the past it inhabited the Continental area from Caucasia to Pakistan, but later on it was forced out by newly originated, now—a major lineage of subsp. tauschii, marked by Got2 ¹⁰⁰. This lineage extended the Continental area of the species up to Kirgizstan, but actually failed to penetrate into pre-Caspian area, occupied by subsp. strangulata. These results essentially differ from those obtained previously, using chloroplast DNA (cpDNA) sequences polymorphism. As revealed by cpDNA, the major, “usual”, subsp. strangulata (TauL2) is “younger” than subsp. tauschii, which resided on phylogenetic tree between relict lineage “t-9¹s”of subsp. strangulata—and major subsp. strangulata. But both cpDNA and Got2 DNA sequences indicate that the level of genetic variation in subsp. tauschii is much lower than in subsp. strangulata. According to Got2 DNA sequences variation, it was Ae. tauschii subsp. strangulata lineage “k-109″ which donated genome D to Triticum aestivum L. This lineage includes accessions: k-109 from South-Eastern Precaspian Azerbaijan; KU-2105, KU-2159 from Western Precaspian Iran; KU-2080 from Eastern Precaspian Iran.     

Morphological variation related with environmental factors in endemic and threatened <Emphasis Type="Italic">Jatropha</Emphasis> species of Tehuacan-Cuicatlan,Mexico

Jatropha spp. from Mexico includes high species richness and endemism; five species inhabit in the Tehuacan-Cuicatlan Biosphere Reserve (TCBR), and they are important resources as food, medicine and biofuel. The assessment of morphological and agronomic characteristics is essential to identify, use and maintain plant genetic resources. Given the lack of information on the morphological variability of Jatropha species in relation to environment, the objective was to analyze the influence of physiographic, climatic, and anthropogenic factors in the morphological variability of the species: Jatropha neopauciflora and J. rzedowskii, both not-endangered; J. oaxacana, special protection; J. ciliata and J. rufescens, both endangered in the Reserve. Twelve quantitative morphological variables were measured in 24 populations of these species; 14 environmental variables were registered, and the disturbance index in the sites was estimated. The information was analyzed with Principal Components Analysis (PCA), Cluster Analysis and Canonical Correspondence Analysis (CCA). PCA detected interspecific variation: J. ciliata and J. rufescens have longer and broader leaves and longer flowers, while the other three species have smaller leaves and flowers. J. oaxacana population has intermediate size of leaves, fruits and seeds, compared with those of J. neopauciflora and J. rzedowskii. CCA detected intra-specific variation among the populations of J. neopauciflora and J. rzedowskii, which were separated in two groups due to fruit and seed size. Axis 1 of CCA correlated positively with altitude and annual temperature range, and negatively with mean annual temperature; at the intra-specific level, both species are adapted to variations of temperature and altitude.     

Oxygen Transfer Numerical Investigation Using Intermittent Aeration Technology Under Regular Waves

Based on a combination of Reynolds-Averaged Navier-Stokes equations, standard k-ε equations, and VOF technique, a 2-D dissolved oxygen transport mathematical model was conducted to investigate oxygen-supply characteristics for regular waves with a given still water depth d and various hydrodynamic parameters (incident wave height H and wave period T equivalent to incident wave length L) and intermittent aeration parameters (air flow rate per unit width q, aeration period T_a, aeration depth d_a and air source area A_a). A series of experiments were conducted to validate the mathematical model, and they agreed well with each other. In addition, a series of dimensionless parameters were conducted to assess their relationships with oxygen transfer coefficient respectively. It was found that oxygen transfer coefficient increased slightly with the increase of \( q/{g}^2{T}_a^3 \). With the increasing \( {d}_a^2/{A}_a \), oxygen transfer coefficient increased obviously for the small \( {d}_a^2/{A}_a \) scenarios; however, it increased slightly for the high \( {d}_a^2/{A}_a \) scenarios. With increasing HL/d², a linear increase tendency of oxygen transfer coefficient appeared approximately. Furthermore, a simple prediction formula for oxygen transport coefficient was conducted using the numerical data, the dimensional analysis, and the least squares method, and it was validated well with the related experimental data.     

Relationships among <Emphasis Type="Italic">Crataegus</Emphasis> accessions sampled from Hatay,Turkey, as assessed by fruit characteristics and RAPD

The genus Crataegus known as hawthorns, is the largest genus among the Maloideae, which comprises 265 species. Turkey is one of the genetic centers of Crataegus and there are more than 20 species found in Turkey. The fruits of Crataegus are used as food and have high flavonoid, vitamin C, glycoside, anthocyanidin, saponin, tannin, and antioxidant levels. In this study, we attempted to characterize 15 Crataegus accessions sampled from Hatay, located in Eastern Mediterranean region of Turkey. The accessions belonged to several species; C. aronia (L.) DC. var. aronia, C. aronia var. dentata Browicz, C. aronia var. minuta Browicz, C. monogyna Jacq. subsp. azarella (Griseb.) Franco, and C. orientalis Pall. ex M. Bieb. var. orientalis. Fruit characteristics of the accessions exhibited considerable variation. The multivariate, principle component and cluster analyses indicated that the accessions belonged to three groups: (1) C. aronia var. arona accessions; (2) C. aronia var. dentata accessions; and, (3) C. monogyna subsp. azarella and C. orientalis var. orientalis accessions. The principle component analysis results also revealed that the first three components explained 46, 21, and 14% of the variation, comprising a total of 81%. The fruit length and width, leaf area, and soluble solids contents were highly correlated characteristics for the first three components. The 19 RAPD primers generated a total of 107 bands, where 76 of these were polymorphic. The molecular data analyses by principle coordinate and clustering showed similar results to those of pomological characteristics. There were three groups, (1) C. aronia var. arona accessions; (2) C. aronia var. dentata accession; and, (3) C. monogyna subsp. azarella. C. orientalis var. orientalis accession grouped with C. aronia var. arona accessions. Therefore, it can be concluded that, overall, the diversity patterns of pomological and molecular data, generated by RAPD, for Crataegus are in good agreement and the accessions of C. aronia var. aronia, C. aronia var. minuta, C. monogyna subsp. azarella and C. orientalis var. orientalis accessions.     

Accumulation and phytoremediation of Pb,Zn, and Ag by plants growing on Koshk lead–zinc mining area,Iran

Purpose

This study investigated the extent of metal accumulation by plants colonizing a mining area in Yazd Province in Central Iran. It also investigated the suitability of these plants for phytoextraction and phytostabilization as two potential phytoremediation strategies.

Materials and methods

Plants with a high bioconcentration factor (BCF) and low translocation factor (TF) have the potential for phytostabilization, whereas plants with both BCFs and TFs >1 may be appropriate for phytoextraction. In this study, both shoots and roots of 40 plant species and associated soil samples were collected and analyzed for total concentrations of trace elements (Pb, Zn, and Ag). BCFs and TFs were calculated for each element.

Results and discussion

Nonnea persica, Achillea wilhelmsii, Erodium cicutarium, and Mentha longifolia were found to be the most suitable species for phytostabilization of Pb and Zn. Colchicum schimperi, Londesia eriantha, Lallemantia royleana, Bromus tectorum, Hordeum glaucum, and Thuspeinantha persica are the most promising species for element phytoextraction in sites slightly enriched by Ag. Ferula assa-foetida is the most suitable species for phytostabilization of the three studied metals. C. schimperi, L. eriantha, L. royleana, B. tectorum, M. longifolia, and T. persica accumulated Ag, albeit at low level.

Conclusions

Our preliminary study shows that some native plant species growing on this contaminated site may have potential for phytoremediation.