Osservazioni sulla polistelia in Primula glaucescens Moretti e Primula longobarda Porta

Abstract

Notes on the polystelic structure in Primula glaucescens Moretti and Primula longobarda Porta. — The rhizome anatomy of Primula glaucescens Moretti and Primula longobarda Porta (two species endemic to Lombardy) have been studied. It has been found that the polystelic structure is present in the rhizome of both species, but with some differences. The taxa show a difference in the number and size of steles and amount of sclerenchymatic tissue within the single stele.

Our investigations confirm the necessity to separate in a specific rank Primula glaucescens Moretti from Primula longobarda Porta, as already proposed by Arietti and Crescini (1976).     

The Genus Primula: Section Muscarioides

ABSTRACT

Background: Hybrid zones provide excellent opportunities for studying plant adaptation and speciation.

Aims: We tested whether two herbaceous species of Senecio, S. vernalis and S. glaucus, hybridise in the eastern Mediterranean region and form a hybrid zone across an aridity gradient in the Jordan Rift Valley.

Methods: Allozyme variation surveyed across both species was analysed by the programme STRUCTURE to assign individuals to genetic groups and determine levels of admixture. Populations in the Jordan Rift Valley were subsequently subjected to a cline analysis.

Results: STRUCTURE showed that interspecific hybrids were produced at low frequency along the Israeli coastal plain where S. glaucus is represented by ssp. glaucus. In contrast, hybrids were more commonly produced in central populations of the Jordan Rift Valley. Here, the two species form a hybrid zone with S. vernalis occurring in mesic sites to the north and S. glaucus (ssp. coronopifolius) in arid sites to the south. Cline analysis showed that the hybrid zone is centred towards the northern end of the Dead Sea, but the analysis failed to distinguish how it is maintained.

Conclusions: Future detailed genetic and ecological analysis of the Senecio hybrid zone should improve our understanding of plant adaptation and speciation across aridity gradients.     

Primula zhui (Primulaceae) sp. nov. from south Yunnan,southwest China

Primula zhui a new species of Primula endemic to the Yunnan Province, China, is described and illustrated. It is morphologically similar to P. intanoensis from Thailand, and P. calyptrata from southeast Yunnan, affiliated to Primula sect. Carolinella (Hemsl.) Pax. However, it is easily distinguished from the Thailand species by its longer corolla tube and distylous flowers, and it differs from the Chinese species by its leaf ovate to ovate‐elliptic blade and distylous flowers.     

Comparative study of pollination biology of two closely related alpine Primula species,namely Primula beesiana and P. bulleyana (Primulaceae)

Abstract The comparative pollination biology of a population of Primula beesiana, a population of P. bulleyana, and an overlapping population of these two species in Yulong Shan, Yunnan Province, China, was studied in 2004 and 2005. The results indicate that both P. beesiana and P. bulleyana are typical heterostylous and obligate outcrossing species; the main pollinators of the two species were bees and butterflies. At the sites of all three populations, the main pollinating visitors of the two species showed preference for one of the two species, resulting in the ethological isolation of the two species by the pollinators. This ethological isolation contributes to the reproductive isolation of the two species, which supports the hypothesis that P. beesiana and P. bulleyana are two distinct species. The reproductive isolation of the two species (ethological isolation) is probably an important mechanism in maintaining species boundaries in the genus and has contributed to the species diversification of Primula in the area. In addition, gene exchanges between P. beesiana and P. bulleyana has occurred to some extent in the overlapping population, but whether natural hybridization has contributed to species diversification in Primula remains to be determined.     

Primula vallicola sp. nov. (Primulaceae) from Sichuan,China

A new species of Primula, P. vallicola Y. Xu, G. Hao & C.M. Hu, is described and illustrated from Sichuan province, China. Based on general morphology the new species is assigned to Primula sect. Aleuritia subsect. Yunnanensis. It is closely allied to P. kialensis, but can be distinguished by its larger stature, leaf shape, and the well‐differentiated petiole. The leaf shape of the new species is ovate to ovate‐elliptic and usually sub‐rounded at base. The new species also resembles P. homogama, but differs in being glabrous rather than with appressed hairs, and with longer petiole.     

Primula persimilis sp. nov. (Primulaceae) from Sichuan,China

A new species of Primulaceae, Primula persimilis G. Hao, C.M. Hu & Y. Xu, from Sichuan, China, is described and illustrated. In general morphology it is allied to the species of P. sect. Monocarpicae, characterized by the presence of multi‐cellular hairs, the distinctly petiolate leaves, a campanulate calyx, and a globose or cylindrical capsule with valvate dehiscence. The new species superficially resembles P. tsiangii W.W. Smith, but can be distinguished by its white flowers, longer calyx lobes, and cylindrical capsules.     

Growth and Differentiation of Root Endodermis in Primula acaulis Jacq.

Adventitious roots of Primula acaulis Jacq. are characterized by broad cortex and narrow stele during the primary development. Secondary thickening of roots occurs through limited cambial growth together with secondary dilatation growth of the persisting cortex. Close to the root tip, at a distance of ca. 4 mm from the apex, Casparian bands (state I of endodermal development) within endodermal cells develop synchronously. During late, asynchronous deposition of suberin lamellae (state II of endodermal development), a positional effect is clearly expressed - suberization starts in the cells opposite to the phloem sectors of the vascular cylinder at a distance of 30 – 40 mm from the root tip. The formation of secondary walls in endodermis (state III of endodermal development) correlates with the beginning of secondary growth of the root at a distance of ca. 60 mm. Endodermis is the only cortical layer of primrose, where not only cell enlargement but also renewed cell division participate in the secondary dilatation growth. The original endodermal cells additionally divide anticlinally only once. Newly-formed radial walls acquire a typical endodermal character by forming Casparian bands and deposition of suberin lamellae. A network of endodermal Casparian bands of equal density develops during the root thickening by the tangential expansion of cells and by the formation of new radial walls with characteristic wall modifications. These data are important since little attention has been paid up till now to the density of endodermal network as a generally significant structural and functional trait of the root. This revised version was published online in July 2006 with corrections to the Cover Date.     

Primula wawushanica sp. nov. (Primulaceae) from Sichuan,southwestern China

A new species of Primulaceae, Primula wawushanica G. Hao, C. M. Hu & Y. Xu, from Sichuan, China, is described and illustrated. In general morphology it is clearly allied to P. sect. Petiolares subsect. Davidii, characterized by firmly papery or leathery leaves, with adaxially impressed veins which are often prominently raised and alveolate abaxially. However, from other species of this subsection, P. wawushanica is distinguished by its glabrous and sessile leaves, smaller flowers, and by the shorter scape at flowering time.     

Primula jiugongshanensis sp. nov. (Primulaceae) from China,based on morphological and molecular evidence

Primula jiugongshanensis J. W. Shao, a new species from Mt Jiugongshan in Hubei Province, China, is described and illustrated. This species is a biennial glabrous herb with pinnately compound leaves, and affiliated to P. sect. Ranunculoides C. M. Hu. It is distinguished from other species of the section by outer simple leaves ovate, flowers distylous, corolla lobe apex conspicuously emarginate, and lack of bulblets. Molecular phylogenetic analysis of nrDNA internal transcribed spacer sequences (ITS) was conducted and the results also supported the recognition of P. jiugongshanensis as a new species. The species is known from only three separated unprotected populations and is categorized as ‘Endangered’ (EN).     

Isolation and characterization of microsatellites in Primula glaucescens Moretti and their cross-species amplification in P. spectabilis Tratt.

The hexaploid herbaceous species Primula glaucescens Moretti and Primula spectabilis Tratt. (2n = 6x = 66) are two endemics of the Italian Pre-Alps protected by national and international laws. In order to plan conservation strategies for natural populations and to study the influence of the latest glaciation on them we developed a set of microsatellites markers for the endangered Primula species: ten primer pairs allowed analysis of polymorphic disomic loci in P. glaucescens samples and seven of them also amplified polymorphic disomic markers in P. spectabilis. Kirsten Wolff and Giorgio Binelli contributed equally to the paper     

Evidence of hybrid speciation in the North American primroses Primula suffrutescensP. parryiP. rusbyi and P. angustifolia (Primulaceae)

The genetic structure of tetraploid (4x = 44) North American species of Primula subgenus Auriculastrum: P. suffrutescens, P. parryi, P. rusbyi, and P. angustifolia was analyzed at seven enzyme loci and compared with that of the related diploid P. cuneifolia and P. nipponica. The studied tetraploid species showed fixed or almost fixed heterozygosity at various loci, indicating a hybrid origin. About half of their alleles were shared with Cuneifolia taxa sampled, suggesting that they arose from crosses involving a maternal Cuneifolia-like ancestor. A preliminary survey of their possible paternal species, as inferred from their genotypes, was carried out among different Primula groups. Several paternal alleles expected were observed in subgenus Aleuritia, particularly among taxa of sect. Crystallophlomis (e.g., P. chionantha, P. minor, and P. nivalis xanthobasis). However, none of these taxa proved to be a suitable paternal species. Hybridization events that originated P. suffrutescens, P. parryi, P. rusbyi, and P. angustifolia presumably occurred during Pleistocene secondary contacts in Beringia and involved a maternal Cuneifolia-like ancestor and at least two paternal species, for sect. Suffrutescens and Parryi, respectively. Further studies, involving a genetic survey of Aleuritia taxa from Siberia will be needed to detect such paternal species, if not extinct.     

Phylogenetic relationships and character evolution in Primula L.: The usefulness of ITS sequence data

ABSTRACT

The main goals of this research were to reconstruct the infrageneric phylogeny of the genus Primula based on both nuclear and chloroplast DNA sequences, and to use the resulting phylogenies to elucidate the evolution of breeding systems, morphological characters, chromosome number, and biogeographic distribution in the genus. In this paper, the results of a pilot study based on the nuclear ribosomal Internal Transcribed Spacer (ITS) region are described. ITS sequences from 21 taxa produced a number of variable characters sufficient to resolve relationships among sections. The resulting phylogeny confirmed the monophyly of sections Auricula and Aleuritia. Sections Armerina, Proliferae, Crystallophlomis, Parryi, and Auricula, with a base chromosome number of x = 11, and sect. Aleuritia, with a base chromosome number of x = 9, formed two well supported clades. The ITS topology also suggested that leaves with revolute vernation, previously believed to be a derived state, might represent the ancestral condition in Primula, with later reversals to the involute condition. Finally, this initial ITS tree provides preliminary support to the proposed role of the widespread, diploid and heterostylous P. mistassinica as having given origin to the polyploid, homostylous P. incana and P. laurentiana.     

Breeding system of the threatened endemic Primula cusickiana var. maguirei (Primulaceae)

Maguire primrose (Primula cusickiana var. maguirei) is a threatened, narrow endemic found only along a 20‐km section within a single canyon in northern Utah, USA. Here we describe the breeding strategy of this perennial, distylous, primarily cliff‐dwelling species to test for reproductive constraints on the plants. Intermorph outcrossing treatments (i.e. between pin and thrum flowers) were the most successful hand pollinations performed, but those were usually inferior to natural pollination. Intramorph out‐crossing also was somewhat successful, but was consistently inferior to intermorph outcrossing. Seed‐set resulting from autogamy and geitonogamy treatments was least successful. Morph‐specific differences in seed set were observed for our hand pollinations, but not in natural pollination conditions. Our results suggest that pollinators play a crucial role by providing the pollen transfer necessary for maximal seed set in this rare and narrowly distributed distylous plant.     

Antimicrobial and cytotoxicity activities of the medicinal plant Primula macrophylla

Primula macrophylla (Primulaceae) is reported as to be useful in asthma, restlessness, insomnia and fish poisoning. Antifungal and toxic activities of crude extract, fractions and a pure isolated compound exhibited statistically significant activities. Excellent antifungal activity was found in the crude extract, benzene and ethyl acetate fractions against T. longifusis and against M. canis with different MIC values. Antileishmanial activity (IC₅₀ = 50ug/mL) was observed as compared to standard drug Amphotericin B, and cytotoxic activity (LD₅₀ = 47.919μg/mL) was also found in the chloroform fraction. While pure compound 2-phenylchromone (Flavone) isolated from the chloroform fraction showed good activity (IC₅₀ = 25μg/mL) against Leishmania and cytotoxicity (LD₅₀ = 2.0116 μg/mL) in Brine Shrimp experiments. From antileishmanial and cytotoxic activity it can be concluded that 2-phenylchromone is the major compound responsible for these activities.     

Primula cusickiana (Primulaceae) and its varieties

Primula domensis Kass & S. L. Welsh,P. maguirei L. O. Williams, andP. nevadensis N. H. Holmgren are reduced to varietal status underP. cusickiana (A. Gray) A. Gray.     

Calcium uptake from the stigma by germinating pollen in Primula officinalis L. and Ruscus aculeatus L.

Summary The flow of calcium ions from the stigma to germinating pollen was studied by autoradiography in Primula officinalis (dry stigma) and Ruscus aculeatus (wet stigma). ⁴⁵Ca²⁺ ions were observed to be taken up by the pistils from an agar medium and then transported intracellularly to both the stigmal cells and the stigmal exudate. The ⁴⁵Ca²⁺ present in the stigma was taken up by the germinating pollen grains.     

Identification of effective pollinators of Primula sieboldii E. Morren in a wild habitat in Hiroshima,Japan

Primula sieboldii E. Morren is a heterostylous clonal herb that is widely distributed in Japan but in danger of extinction in the wild. The existence of pollinators in each habitat is imperative for its long-term survival, because seeds can be produced only by insect cross-pollination between different flower morphs. In this study, we identified the pollinators of P. sieboldii in a wild habitat in Hiroshima as those insects that we observed to (a) put the proboscis into a corolla tube, (b) deposit pollen grains on the proboscis, and (c) have a proboscis of appropriate length and width. Effective pollinators were identified from their contribution to pollination. In 2015 and 2016, the flower visitations of 232 and 558 insects, respectively, were recorded and 85 and 13 insects were captured. Two Bombylius species, B. major L. and B. shibakawae Matsumura, accounted for 90% of flower-visiting insects in both years. All 14 species that we captured were considered pollinators of P. sieboldii, because they had proboscises that were long enough to reach pollen and that had pollen grains deposited on them. The total visitation rate of “Bombyliidae” was the highest among all pollinator categories. The results of potential pollen transport per flower per hour, which was based on total pollen number and total visitation rate of each pollinator category, indicated that “Bombyliidae” species were the most effective pollinators of P. sieboldii in this habitat.     

Differences in ploidy levels of inter-specific hybrids obtained by reciprocal crosses between Primula sieboldii and P. kisoana

Differences in ploidy level were found in inter-specific hybrids obtained by reciprocal crosses between Primula sieboldii and P. kisoana. When P. sieboldii was used as the maternal parent, the inter-specific hybrids were triploids; when P. kisoana was the maternal parent, the inter-specific hybrids were diploids. The possibility of diploid female gamete formation in P. sieboldii is discussed as a causal factor in the production of triploids occasionally found in crosses between diploids of this species. Received: 28 December 1999 / Accepted: 10 January 2000     

Molecular Characterization of Extrachromosomal DNA Accompanying Primula Red Phytoplasma

The complete nucleotide sequence of an extrachromosomal element found in primula red isolate of ‘Candidatus Phytoplasma asteris’ (16SrI‐B subgroup) was determined. The plasmid, named pPrR, is 4378 bp in length and has 75% A+T content that is similar to that of the phytoplasma genome. It encodes six putative open reading frames (ORF) longer than 100 amino acids and two smaller ones. The structural organization of the rep gene is similar to that found in plasmids which replicate via rolling circle mechanism. Furthermore, it has homology to both the plasmid pLS1 family and helicase domains of replication‐associated proteins (Rap) of eukaryotic viruses and geminiviruses. The ORF arrangement and genes sequences are most similar to the pPARG1 plasmid from ‘Rehmannia glutinosa’ phytoplasma.     

Very-Long-Chain Wax Constituents from Primula veris and P. acaulis: Does the Paradigm of Non-Branched vs. Branched Chain Dominance Universally Hold in all Plant Taxa?

Herein n-, iso- and anteiso-series of very-long-chained (VLC) alkanes (C₂₁–C₃₅), fatty acid benzyl esters (FABEs; C₂₀–C₃₂), and 2-alkanones (C₂₃–C₃₅) were identified in the wax of Primula veris L. and P. acaulis (L.) L. (Primulaceae). For the very first time in a sample of natural origin, the presence of iso- and anteiso-VLC FABEs and 2-alkanones was unequivocally confirmed by synthetic work, derivatization, and NMR. It should be noted that the studied species produced unusually high amounts of branched wax constituents (e. g., >50 % of 2-alkanones were branched isomers). The domination of iso-isomers, probably biosynthesized from leucine-derived starters, is a unique feature in the Plant Kingdom. The plant organ distribution of these VLC compounds in P. acaulis samples (different habitats and phenological phases) pointed to their possible ecological value. This was supported by a eutectic behavior of binary blends of FABEs and alkanes, as well as by high UV-C absorption by FABEs.