Chemotaxonomic significance of flavonoids and phenolic acids in the Hieracium rohacsense group (Hieracium sect. Alpina; Lactuceae, Compositae)

Five apomictic taxa from the Hieracium rohacsense group were studied for their phenolic constituent composition. The following substances represent dominant compounds in the leaves: chlorogenic acid, 3,5-dicaffeoylquinic acid, luteolin 7-O-β- -glucopyranoside, luteolin 4′-O-β- -glucuronopyranoside and apigenin 4′-O-β- -glucuronopyranoside. Within the group only quantitative differences were found, luteolin 7-O-glucoside being the most important chemotaxonomic marker. Each taxon has its own specific quantitative pattern, invariable within the taxon. Based on these characteristic profiles, H. rohacsense can be distinguished from a closely related and still undescribed taxon from Mt. Pip Ivan. The proportion of luteolin 7-O-glucoside to apigenin 4′-O-glucuronoside also clearly separates the individuals of two morphologically close species—H. ratezaticum and H. pseudocaesium, which corresponds to a few slight but recognisable morphological and phenological characteristics. The ontogenetic stage of leaf development and seasonal variation are also important factors, which must be taken into consideration, as the quantity of the substances changes during leaf ontogeny and with season.     

Floral scent and its correlation with AFLP data in Sorbus

Comparisons between floral scent-based and DNA-molecular-based taxonomies are rare, yet such comparisons indicate that scent can provide useful taxonomic information. Here, we correlate the phytochemical differentiation in floral scent to the DNA-molecular-based differentiation in the genus Sorbus. Inflorescence scent patterns of the apomictic and endemic Sorbus latifolia microspecies Sorbus franconica, Sorbus adeana, and Sorbus cordigastensis originated by hybridization as well as their parental taxa Sorbus aria agg. and Sorbus torminalis were investigated with the dynamic headspace method. The scent data (presence/absence of compounds) were used to construct an UPGMA tree, to calculate a similarity matrix, and to correlate them with the published amplified fragment length polymorphism (AFLP) data of the same individuals, populations, and taxa. Flow cytometry was used to estimate the DNA-ploidy level of the taxa. Scent analyses showed a total of 68 substances, among them aromatic compounds, terpenoids, aliphatics, and nitrogen-containing compounds. The scent patterns were taxon-specific, and the number of scent components differed among taxa. The correlations with the published AFLP data on population and individual level are highly significant, indicating that the scent and AFLP data are highly congruent in the plants studied. Scent therefore provides useful taxonomic characters in Sorbus.     

Trap gland morphology and its systematic implications in Taiwan Utricularia (Lentibulariaceae)

The highly specialized trap glands of carnivorous plant are responsible for the digestion and absorption of the prey; however, there are few studies on their systematics and evolution. In this study, the gland morphology of six carnivorous plant species of the genus Utricularia (Lentibulariaceae) in Taiwan, including U. aurea Lour., U. australis R. Br., U. bifida L., U. caerulea L., U. gibba L. and U. striatula Sm., was examined with a scanning electron microscope. The glands on both the outer and inner surfaces of the traps were examined. We found that the external glands had little diagnostic value, but the internal glands could be used in the identification of Taiwan species. Evolutionary trends of gland characteristics are discussed, analyzing morphology of the internal glands, based on previous work. A new hypothesis for the evolution of internal gland structure in Utricularia is also proposed.     

AFLP fingerprinting of Colombian Clostridium spp strains, multivariate data analysis and its taxonomical implications

Amplified Fragment Length Polymorphism (AFLP) analysis was used for characterising 13 native Colombian Clostridium spp strains. The DNA extraction method was optimised and the use of cetyl trimethyl ammonium bromide (CTAB) and sodium chloride (NaCl) was incorporated. All strains could be typed in these conditions. The AFLP profiles obtained were submitted to multivariate analysis and compared with previous pulsed field gel electrophoresis (PFGE) results. The results suggested that the set of native strains could correspond to two new species different to those having been described to date. It is proposed that DNA-DNA hybridisation analysis should be done to produce complementary information for describing the new species.     

Floral anthocyanins in the genus Puya

A survey of floral anthocyanins among ten species of Puya shows the predominant pigment to be delphinidin 3,7,3′-triglucoside. This is the first report of the natural occurrence of this pigment in a non-acylated form. The occurrence of this unusual glucosylation pattern in Puya supports a close alliance between the Bromeliaceae and Commelinaceae.     

Exudate flavonoid aglycones of Veronica: Ecological and systematic implications

A survey on the distribution of surface flavonoid aglycones in 52 samples of 29 species of Veronica resulted in detection of eight flavone aglycones. Apigenin and luteolin were the most common constituents of the studied exudates, followed by the methylated derivatives apigenin 4′-methyl ether, apigenin 7,4′-dimethyl ether and luteolin 3′-methyl ether. Some intraspecific variations and the main ecological trends of flavonoid aglycone accumulation in Veronica were discussed. The observed exudate profiles appeared to be characteristic for some related groups within the genus, in agreement with the morphological, karyological, molecular and other chemical data.     

Host specificity of a Brazilian mistletoe, Struthanthus aff. polyanthus (Loranthaceae), in cerrado tropical savanna

The aim of this study was to determine if the mistletoe Struthanthus aff. polyanthus shows host specificity, and if host abundance and twig architecture influence this specificity in Cerrado (senso strictu). An area of 1.3 ha of natural savanna was sampled for the occurrence of the mistletoe. The twigs of the hosts were classified as vertical or horizontal, and the bark as smooth or rough. We sampled a total of 666 trees in the study site and 118 individuals (17.7%) hosted S. aff. polyanthus. The abundance of mistletoe was significantly affected by the bark type, but not by the twigs inclination. In the cerrado, S. aff. polyanthus seems to be a generalist, with a tendency to be more common on some hosts (Kielmeyera coriacea, Pouteria ramiflora and Styrax ferrugineus), prefering that with rough bark type.     

Floral scent chemistry and pollination ecology in phytelephantoid palms (Arecaceae)

The subfamilyPhytelephantoideae comprises three genera (Ammandra, Aphandra, andPhytelephas) and seven species of dioecious palms. The floral scents ofAmmandra dasyneura, A. decasperma, Aphandra natalia, Phytelephas aequatorialis, P. macrocarpa, andP. seemannii were analyzed by gas chromatography-mass spectrometry. We studied the pollination biology ofA. natalia, P. aequatorialis, andP. macrocarpa, and tested how the synthetically produced main constituents of the floral scents ofAphandra andPhytelephas attracted insects in two natural populations ofPhytelephas. The genera are distinct in terms of floral scents.Ammandra has sesquiterpenes,Aphandra (+)-2-methoxy-3-sec-butylpyrazine, andPhytelephas p-methyl anisol. These constituents dominated the scents quantitatively and qualitatively. The similarity between scents of male and female inflorescences was 76.5% inAmmandra, 84.2% inAphandra, and >99% inPhytelephas. Different species ofAleocharinae (Staphylinidae) pollinateAphandra natalia andPhytelephas species and reproduce in their male inflorescences.Derelomini (Curculinoidae) andMystrops (Nitidulidae) only visit and pollinatePhytelephas in which male inflorescences they reproduce. A species ofBaridinae (Curculionidae) only visits and pollinatesAphandra natalia, and reproduces in its female inflorescence. The apparent reliance on one or a few floral scent constituents as attractants and few and specific pollinators may indicate co-evolution. Sympatric species ofPhytelephantoideae have different scents. We suggest that species with similar scents have allopatric distributions due to the absence of a pollinator isolation mechanism.     

Characterization of the expression of a desiccation-responsive rd29 gene of Arabidopsis thaliana and analysis of its promoter in transgenic plants

Summary We characterized the expression of genes that correspond to a cDNA clone, RD29, which is induced by desiccation, cold and high-salt conditions in Arabidopsis thaliana. Northern analysis of desiccation-induced expression revealed a two-step induction process. Early induction occurs within 20 min and secondary induction occurs 3 h after the start of desiccation. Exogenous abscisic acid (ABA) induces RD29 mRNA within 3 h. Two genes corresponding to RD29, rd29A and rd29B, are located in tandem in an 8 kb region of the Arabidopsis genome and encode hydrophilic proteins. Desiccation induces rd29A mRNA with two-step kinetics, while rd29B is induced only 3 h after the start of desiccation. The expression of both genes is stimulated about 3 h after application of ABA. It appears that rd29A has at least two cis-acting elements, one involved in the ABA-associated response to desiccation and the other induced by changes in osmotic potential. The -glucuronidase (GUS) reporter gene driven by the rd29A promoter was induced at significant levels by desiccation, cold, high-salt conditions and ABA in both transgenic Arabidopsis and tobacco. Histochemical analysis of GUS activity revealed that the rd29A promoter functions in almost all the organs and tissues of vegetative plants during water deficiency.     

Biological properties of the endemic and threatened shrub in Iberia Vella pseudocytisus subsp. paui Gómez Campo (Cruciferae) and implications for its conservation

We present new data about chorology, seed bank, dispersal, seedling biology and population structure of the threatened endemic shrub Vella pseudocytisus subsp. paui Gómez Campo in Spain. In addition, we investigate human activities that are linked with the fine-scale distribution of the taxon to offer conservation recommendations.Currently, the plant occurs in two populations close to the city of Teruel (East central Spain), growing in an open shrubby community on patches of gypsum substrate surrounded by agricultural landscape. The plant has disappeared from two reported locations dated from early 20th Century likely due to human activities.The seed bank seems to be poor. A ballistic dispersal mechanism appears to move seeds between 0 and 4 m. We did not find a clear seasonal pattern of seedlings emergence although spring cohorts are the largest. Also, this period was where leaf seedling growth was more prominent. During the 3 years of our survey, the cumulative mortality was 94.2% of all seedlings plants. Plants are estimated to remain in the seedling stage for approximately 5 years. The demographic structure of both populations shows no apparent gaps in the distribution of size classes. Adult plants greater than 200 dm³ represent the most important stage for seed production and persistence.We point out two key factors for conservation purposes, first the weakness of some of the plant biological properties for natural establishment and second its ability to colonise artificial environments. We propose a mitigation of clonal spread in those sites and the protection of juvenile stages in more natural locations.     

Genetic diversity of the endangered Brazilian endemic herb Cunila menthoides Benth. (Lamiaceae) and its implications for conservation

Cunila menthoides is classified as a xylopodiferous subshrub found in fragmented environments threatened by local agriculture and pasture activities. The species presents strong and pleasant smell, and is commonly used in south Brazilian folk medicine. Based on the species’ medicinal and aromatic potential, the aim of this work was to examine the genetic variation within and among C. menthoides populations, focusing on the conservation of this species. In this context, six C. menthoides populations collected in Rio Grande do Sul, Brazil, were analyzed by ISSR. The populations were sorted as four clusters according to geographic distribution. The six C. menthoides populations analyzed presented low genetic variability, indicating that each population derives from a limited number of plants in a low gene flow scenario. In situ and ex situ conservation approaches may be useful in this species. Conservation strategies for the species should be based on in situ and ex situ approaches.     

Flavonoids and the taxonomy of Camarea (Malpighiaceae)

Camarea is a South-American endemic genus comprising eight species. In the present work leaf flavonoids of seven species of Camarea were identified, aiming to evaluate the usefulness of their distribution as a taxonomic aid. A total of 12 flavonoids were isolated and identified. Free aglycones, such as apigenin, chrysoeriol, kaempferol and quercetin, as well as 7-O-glycosides of apigenin and luteolin, 3-O-glycosides of kaempferol and quercetin were identified. Flavonoid distribution in Camarea species, taking into account aglycones and aglycone moieties of glycosides, was used to obtain a phenogram of chemical affinities. Apigenin, chrysoeriol and kaempferol were the main discriminating characters for links establishment. The resultant tree suggests the links: 1) Camarea hirsuta, Camarea affinis and C. affinis × C. hirsuta; 2) Camarea elongata and Camarea axillaris; 3) Camarea sericea and Camarea humifusa. The results are in agreement with morphological similarities and disagree with several points of n-alkane evidence. The results support the recognition of Camarea triphylla as synonymy of C. axillaris.     

Affinities of Phylacia and the daldinoid Xylariaceae, inferred from chemotypes of cultures and ribosomal DNA sequences

A chemotaxonomic evaluation using hplc profiling was undertaken to resolve the infrageneric and intergeneric affinities of over 150 strains of Xylariaceae. Daldinia placentiformis, Hypoxylon nicaraguense, H. polyporus, and Phylacia sagrana were found to contain 8-methoxy-1-naphthol, which is apparently absent in Annulohypoxylon, Hypoxylon, and related genera with bipartite stromata. D. placentiformis and other species of Daldinia and Entonaema produced this naphthol, 5-hydroxy-2-methylchromone, isosclerone derivatives, and ‘AB-5046’ phytotoxins. Phylacia sagrana differed from most Daldinia spp., except for D. caldariorum, by producing eutypine derivatives in addition to the above compounds. Indolylquinones were observed in H. nicaraguense and H. polyporus. Isosclerones were also identified in the A. multiforme complex, but Hypoxylon and other Annulohypoxylon and most Hypoxylon spp. studied Annulohypoxylon spp. contained 5-methylmellein as the major metabolite of their cultures. Based on the occurrence of the above metabolites, further mellein-type dihydroisocoumarins, teleomorphic and anamorphic Xylariaceae with Nodulisporium-like anamorphs (‘Hypoxyloideae’) were divided into various chemotypes. A comparison of their 5.8S/ITS nuc-rDNA sequences agreed in some important aspects with the above results: H. nicaraguense and H. polyporus appeared basal to a clade comprising Daldinia, Entonaema, and Ph. sagrana. The latter species appeared allied to D. caldariorum, but was distantly related to Pyrenomyxa morganii and Hypoxylon s. str.     

Chemical tools to distinguish the fire ant species Solenopsis invicta and S. saevissima (Formicidae: Myrmicinae) in Southeast Brazil

Morphologically similar fire ants Solenopsis invicta and Solenopsis saevissima are broadly sympatric in southeastern Brazil. Chemistry from venom (2,6-dialkyl piperidine alkaloids) and cuticular hydrocarbons have been reported as potentially important tools for differentiating Solenopsis species. We have analysed two chemical classes in widely separated populations of S. invicta and S. saevissima and find that both piperidine alkaloids and cuticular hydrocarbons separate the two species. Piperidine alkaloids clustered S. invicta but not S. saevissima. Cuticular hydrocarbons strongly clustered both S. invicta and S. saevissima. One population morphologically identified as S. invicta presented piperidine alkaloids and cuticular hydrocarbons markedly different from either species. The distinctive piperidine alkaloid differences among populations of S. saevissima and the marked difference in piperidine alkaloid and hydrocarbon profiles of the anomalous population of S. invicta suggest undescribed species fire ant in southeastern Brazil.     

Molecular evolution of 5S rDNA region in Vigna subgenus Ceratotropis and its phylogenetic implications

The evolution of 5S rRNA gene unit (5S gene unit) was studied among the ten species belonging to Vigna subgenus Ceratotropis by sequencing and analyzing the intra- and inter-specific sequence heterogeneity. The 5S unit from these species ranged from 214 to 342 bp in length as a result of several indels in the intergenic spacer (IGS) region. A large deletion (>100 bp) was found specifically in the IGS of V. radiata accessions. IGS showed high sequence variation with more than 50% polymorphic and 35.4% parsimony informative sites. However, the coding region (5S gene) was highly conserved, both in length and in sequence. Intra-genomic and intra-specific divergence was observed among some species, which indicated that the 5S unit is evolving at different rates among the Vigna species. Most Vigna species harbored one type of 5S unit indicating complete homogenization among them. Vigna glabrescens, a tetraploid species, also showed single type of 5S rDNA from only one of the diploid progenitor indicating loss or homogenization of the other type. However, V. nakashimae and V. riukiuensis harbored multiple, diverse, ‘intra-genomic 5S types’ indicating that 5S rDNA is not completely homogenized by concerted evolution and is still evolving. In general, the phylogeny based on IGS sequences was in agreement with many of the earlier reports except some surprising observations such as, V. glabrescens clustered with V. mungo in section Ceratotropis and unlike most of the species, wild and cultivated types of V. umbellata were present in different subclusters. Presence of divergent 5S sequences in V. nakashimae and V. riukiuensis caused errors in phylogeny reconstruction at species level and suggested a horizontal ‘gene transfer’ as a result of inter-species hybridization. The comparative analysis showed that 5S IGS sequences have better phylogenetic utility than chloroplast DNA sequences, such as atpB-rbcL and is comparable to ITS1 and ITS2 in this respect.     

Floral scent diversity is differently expressed in emitted and endogenous components in Petunia axillaris lines

BACKGROUND AND AIMS: Among the subspecies of Petunia axillaris are various lines emitting sensorially different scents. Analysis of variations in floral scent among genetically close individuals is a powerful approach to understanding the mechanisms for generating scent diversity. METHODS: Emitted and endogenous components were analysed independently to gain information about evaporation and endogenous production in 13 wild lines of P. axillaris. A dynamic headspace method was used to collect emitted components. Endogenous components were extracted with solvent. Both of these sample types were subjected to quantitative and qualitative analysis by gas chromatography (GC)-flame ionization detector (FID) and GC-mass spectrometry (MS). KEY RESULTS AND CONCLUSIONS: Whereas the profiles of emitted compounds showed qualitative homogeneity, being mainly composed of methyl benzoate with quantitative variation, the profiles of endogenous compounds showed both qualitative and quantitative variation. A negative correlation was found between the evaporation ratio and boiling point of each compound examined. Lower boiling point compounds were strongly represented in the emitted component, resulting in the reduction of qualitative variation in floral scent. In conclusion, floral scent diversity results from variation in both the endogenous production and the evaporation rate of the individual volatile compounds.     

Floral scent composition in early diverging taxa of Asclepiadoideae,and Secamonoideae (Apocynaceae)

The Apocynaceae–Asclepiadoideae are well known for their specialized floral morphologies and pollination systems and many species have distinct floral aromas. However, our knowledge on the chemistry of floral volatiles in this plant family is relatively limited although it has been suspected that floral scent plays a key function for pollinator attraction. This is the third paper in a series of papers reporting on the floral odours of Asclepiadoideae. Floral odours of eleven species from seven genera (Cibirhiza, Fockea, Gymnema, Hoya, Marsdenia, Stephanotis and Telosma) of early diverging taxa of Apocynaceae–Asclepiadoideae, and two species of Secamone (Apocynaceae–Secamonoideae) were collected using headspace sampling and then analyzed via GC–MS. We detected 151 compounds, of which 103 were identified. The vast majority of chemicals identified are common components in flower odour bouquets of angiosperms. However, striking was the high relative amount of acetoin (97.6%) in the flower scent of Cibirhiza albersiana. This compound has rarely been reported as a flower scent component and is more commonly found in fermentation odours. Bray–Curtis similarities and Nonmetric-Multidiminsional Scaling (NMDS) analyses showed that each of the species has a distinct odour pattern. This is mostly due to only twelve compounds which singly or in different combinations dominated the scent of the species: the benzenoids benzyl acetate, benzaldehyde, methyl benzoate, and 2-phenylethyl alcohol; the monoterpenoids (E)-ocimene, (Z)-ocimene, linalool, and eucalyptol; and the aliphatic compounds acetoin, and (E,Z)-2,6-nonadienal. The floral scent compositions are discussed in relation to tribal affiliations and their potential role for pollinator attraction, and are compared with the scent data available from other Asclepiadoideae species.