Anna Maria Palermo

Phylogenetic relationships in the orchid genus Serapias L. based on noncoding regions of the chloroplast genome

A molecular phylogenetic analysis was performed on 14 species of the Mediterranean unrewarding orchid genus Serapias using sequences of four noncoding regions of chloroplast DNA. This study has led to a new interpretation of the evolutionary relationships in this genus. The well-defined phylogenetic tree supports a division of taxa into two main clades, each including two minor groups. The molecular relationships found in this study differ from those defined by traditional systematic morphological assessments. By comparing the variation in sequence to variations in floral traits, we propose that the split in the two main lineages reflects an early differentiation of flower size, perhaps due to the shift from allo- to self-pollination. Conversely, the relationships within each minor group do not reflect floral size variation; therefore, we presume that this diversification resulted from genetic drift, local selection forces, and multiple, independent transitions towards self-pollination and polyploidy.

The Conservation Perspectives and Value of Small and Isolated Plant Populations: Preliminary Clues for Gentianella crispata (Gentianaceae) at the Western Boundary of Its Range

We give the first account concerning the ecology, population size, breeding system and genetic variability of the unique Italian population of Gentianella crispata, a rare orophilous species with a disjunct distribution including Balkan peninsula and southern Italy. The population is relatively small (ca. 4000 individuals) and has a fragmented structure within a wider area covered by the grass-dominated vegetation Seslerio nitidae—Brometum erecti. The evaluated morphological traits (i.e. plant size, flower number per plant and length of corolla tube) greatly varied among individuals. Examination of the floral structures revealed that the stigma becomes receptive before anther dehiscence. Observations on the topological relationships between stigma and anther suggested that in young flowers protogyny is paralleled by herkogamy (i.e. hyper-stigmatic condition). However, the anther dehiscence appeared to be accompanied by a reduction of the spatial separation between female and male organs. This suggested the occurrence of a mixed breeding system, as also sustained by ISSR analysis. The ITS-based phylogeny showed an interesting relationship with G. caucasea, conferring a peculiar evolutionary interest to the species and its westernmost, severely isolated Italian population. According to the IUCN Red List criteria, G. crispata in Italy meets the requirements for critically endangered species.

Allozymic variability in Centaurea tenorei Guss. ex Lacaita and in other species of C. parlatoris Heldr. group (Asteraceae)

ABSTRACT The genetic diversity in Centaurea tenorei Guss. ex Lacaita, an endemic species of the “Penisola Sorrentina” (Campania region, Italy), was assessed by comparing the allozymic polymorphisms of its populations, hitherto considered as different formae of this taxon. These forms are discontinuously distributed along the coasts (C. tenorei fo. maritima) and on the internal reliefs (fo. tenorei and fo. montaltensis). Based on unpublished data, C. tenorei fo. tenorei is diploid while the others are tetraploid. In order to compare C. tenorei with the Italian congeneric, strictly related species, this analysis was extended to at least one population of all the other species enclosed in the C. parlatoris Heldr. group, in particular C. parlatoris, C. scannensis and C. ambigua, all known to be diploid. Our results point to a very low genetic diversity (He=0.08; 0.14) in fo. tenorei and fo. montaltensis, while fo. maritima (He=0.26) exhibits levels of allozymic variability similar to those observed in the other populations examined. Moreover, Wrights F statistics suggest a high inbreeding level (Fis=0.42) and a low genetic flow (Fst=0.34) among C. tenorei populations. We propose that the differences among the three forms of C. tenorei may depend upon their population size, mating system and different ploidy level. However, since they fail to form a unique group in the cluster analysis, it is suggested that a probable reticulate evolution obscures the relationships among the examined taxa, which, in any case, started to diverge only in recent times.

Footprint of the eastern euroasian past in Italian populations of Cryptotaenia thomasii (Ten.) DC

BackgroundThe knowledge of the genetic architecture of closely related species and/or populations of a single species can be very useful to shed light on the processes that led to their current distributions. The present study provides a preliminary evaluation of the conservation status of the populations of Cryptotaenia thomasii, a very narrow endemic species occurring in southern Italy. Previous studies showed that C. thomasii was phylogenetically closely related to C. flahaultii, endemic species of Caucasus, and to evaluate its conservation status and the genetic variability of plant species the internal transcribed spacers (ITSs) of nuclear ribosomal DNA were sequenced and the SNPs were analyzed.ResultsThe restriction analysis of nrDNA with the restriction enzymes allowed to detect the presence of two single mutations (SNPs) among the sequences of two species. Our molecular analysis pointed out that C. thomasii and C. flahaultii, in spite of their geographical disjunction, show a sign of an ancient contact as an extreme case of geographical disjunction Italian-Caucasus.ConclusionFrom the evolutionary history of the species and its distribution pattern one can reconstruct a possible scenario with some hypotheses that explain the hypothetical ancestral area where the two species were in contact. We speculate the two species may have originated from fragmentation of a common ancestor widespread in the Western Palearctic zone and have survived in two separated refuge areas limited by important mountain systems. This hypothesis is supported by our molecular analysis, in fact, the analysis of SNPs showed that some C. thomasii populations retain the signs of an ancient link with C. flahaultii.

Genetic diversity and spatial structure in the rare, endemic orophyte Campanula pseudostenocodon Lac. (Apennines, Italy), as inferred from nuclear and plastid variation

Abstract Analysis of ISSR markers revealed a large variation within samples, with polymorphic loci (P) ranging from 42 to 82%, in relation to population size. A consistent genetic differentiation (Gst = 0.207; Φst 29.71%) was found among the four examined populations. Based on changes in the chloroplast trn LEU intron, three distinct haplotypes were identified. Three out of the four populations were fixed for a single haplotype, with the two northernmost populations, which are geographically closest (65 km apart), sharing the same one. These findings suggest that a relatively long period of restricted gene flow originated the present-day spatial structure of C. pseudostenocodon. Application of both nuclear and organelle markers in estimating genetic diversity may be advisable in conservation studies, since they may reveal a peculiar local diversity.

Occurrence of Melampsora gelmii on Euphorbia dendroides: Morphological and molecular observations

Abstract A rust fungus attack was observed on Tree Spurge (Euphorbia dendroides) in two regions of southern Italy. Uredinia and telia of a Melampsora species were detected on the leaves, bracts of the cyathia and capsules of E. dendroides. On the basis of the morphological characteristics and rDNA ITS sequences of the above mentioned structures, the fungus was identified as M. gelmii. This report suggests that M. gelmii seems to be a specific taxon in the M. euphorbiae complex and to be more widespread than previously detected in Italy. Further investigations within the M. euphorbiae complex would be desirable in order to elucidate the identity of M. gelmii as a peculiar form of a still poorly explored species.

Functional differentiation in pollination processes among floral traits in Serapias species (Orchidaceae)

Abstract Floral displays, influencing attractiveness to insects, increase the number of pollinator visits and the efficiency of each visit in terms of pollen exchange and thus affect the plant reproductive success. Here, we conducted an in situ manipulation experiment to investigate whether the floral modifications affect reproductive success in natural orchid populations of Serapias lingua and Serapias vomeracea. We estimated male and female reproductive success of three treatment groups, disassembly of floral tube, cutting of lip, and painting of the callus surface, in terms of pollinaria removed/deposited and fruit production. Results revealed that phenotypic modification had opposite effects on reproductive success of two examine species. Indeed, reproductive success was significantly increased by the detached of the petals and sepals, and decreased, due to callus painting and lip removal, in S. lingua. On the contrary, unmanipulated plants of S. vomeracea showed significantly higher value of pollinaria removed and deposited and fruit set than manipulated ones. The differences between S. lingua and S. vomeracea agree to the different pollination strategy of examined species. S. vomeracea shows shelter imitation strategy, and thus, the disassembly of tunnel‐like corolla does not allow the insects to use the flower as a refuge, while S. lingua is a sexually deceptive orchid and therefore the opening of the flower made more visible callus (visible at a greater distance) increasing the pollinators attraction. This study provides evidence that pollinators were largely sensitive to the experimental modification of the flower phenotype, which is consistent with the presence of significant selection on individual floral characters. Our experimental investigations of the effects of variation in display on pollinator visitation provide insights into the evolution of floral morphology in orchid with shelter imitation strategy.

Who helps whom? Pollination strategy of Iris tuberosa and its relationship with a sexually deceptive orchid

Reproductive success of plants may be affected by interactions with co-flowering species either negatively, through competition for pollinators, or positively, by means of a magnet species effect and floral mimicry. In this study, potential interactions between Iris tuberosa, a rewarding species, and Ophrys fusca, a sexually deceptive orchid, were explored in four populations in southern Italy. In each population plots showing different ratios of the examined species were arranged in the field, and in each plot the number of pollinators and fruit set were assessed. In addition, flower size and floral hydrocarbons produced by the two species were analysed. Morphological and scent data pointed out that flower size and aliphatic compounds did not differ significantly between the two species. Interestingly, both species shared tricosane and 11-nonacosene, electrophysiologically active compounds in the shared dominant pollinator Adrena. We have found that fruit production and number of pollinators in I. tuberosa varied significantly among plots, while percentage of capsules and number of pollinators of O. fusca captured showed no significant differences across plots. These results suggested, that the presence of O. fusca contributes differentially to pollinator attraction, and thus, to total reproductive success of I. tuberosa, according to a different ratio of aggregation. These findings suggest that I. tuberosa profits from the greater abundance of insects attracted by the presence of orchid specimens, and that a sexually deceptive orchid may be a magnet species in pollination strategy.