Genus Primula Research Articles

Unreduced gametes are the major causal factor for the production of polyploid interspecific hybrids in Primula

The genus Primula (Primulaceae) consists of approximately 420 species that mainly inhabit temperate to cold regions of the Northern hemisphere. Although most species have attractive flowers with high ornamental value, few have been cultivated as ornamental plants. To develop novel ornamental crops and to introduce novel useful characters, these unexploited rich germplasms of the genus Primula have the potential to serve as breeding materials through the use of interspecific hybridization. However, interspecific hybrids of this genus have rarely been produced, and embryo rescue is one of the most useful strategies to overcome the difficulty of achieving successful hybridization, especially in wide crosses. In recent studies, we successfully obtained various interspecific hybrids in wide cross combinations in Primula using the embryo rescue technique, and showed that unexpected polyploid hybrids were frequently produced by the fertilization of unreduced female and/or male gametes, which were formed in most of the species examined. Some of the resultant hybrids have useful and attractive characters, and they have already been used directly as novel cultivars or incorporated into commercial breeding of novel types of primulas.

Antimitotic and antibacterial effects of the Primula veris L. flower extracts

Abstract Primula is a plant genus which comprises about 400 species. It has been found in a number of pharmacological studies that primrose extracts are rich in saponins. Phenolic glycosides and saponins are characteristic compounds for the genus Primula. In this study several flower extracts from Primula veris L. has been tested for antibacterial activity and decoction from the flowers has been tested for antimitotic activity. Antibacterial activity was determined by the well diffusion method and Allium cepa L. has been used for evaluating cytotoxicity. Decoction of flowers was toxic on root number and root length in A. cepa L. and reduced the mitotic index significantly. All of the tested P. veris L. extracts showed inhibitory effect against both Gram positive and Gram negative microorganisms at varying degrees. The most effective fraction was found to be the ethanolic.

Strong Genetic Differentiation of Primula sikkimensis in the East Himalaya–Hengduan Mountains

The East Himalaya-Hengduan Mountains region is the center of diversity of the genus Primula, and P. sikkimensis is one of the most common members of the genus in the region. In this study, the genetic diversity and structure of P. sikkimensis populations in China were assessed using inter-simple sequence repeat (ISSR) and chloroplast microsatellite markers. The 254 individuals analyzed represented 13 populations. High levels of genetic diversity were revealed by ISSR markers. At the species level, the expected heterozygosity and Shannon's index were 0.4032 and 0.5576, respectively. AMOVA analysis showed that 50.3% of the total genetic diversity was partitioned among populations. Three pairs of chloroplast microsatellite primers tested yielded a total of 12 size variants and 15 chloroplast haplotypes. Strong cpDNA genetic differentiation (G (ST) = 0.697) and evidence for phylogeographic structure were detected (N (ST )= 0.788, significantly higher than G (ST)). Estimated rates of pollen-mediated gene flow are approximately 27% greater than estimated rates of seed-mediated gene flow in P. sikkimensis. Both seed and pollen dispersal, however, are limited, and gene flow among populations appears to be hindered by the patchiness of the species' habitats and their geographic isolation. These features may have played important roles in shaping the genetic structure of P. sikkimensis. A minimum-spanning tree of chloroplast DNA haplotypes was constructed, and possible glacial refugia of P. sikkimensis were identified.

Primula Culture and Production

The name Primula or primrose is derived from the word primary or first, referring to the early growth and flowering in spring (Liberty Hyde Bailey Hortorium, 1976). More than 400 species of primula exist in the family Primulaceae (Griffiths, 1994). Other important horticultural genera in this family, besides primula, include pimpernel (Anagallis), rock jasmine (Androsace), persian violet, alpine violet or sowbread (Cyclamen), shooting star or american cowslip (Dodecatheon) and loosestrife (Lysimachia). The genus Primula consists of relatively shortlived perennial herbs with leaves arranged in basal rosettes. The flowers are usually five lobed and solitary in axils or arranged in stalked racemes, umbels or whorls (Griffiths, 1994; Liberty Hyde Bailey Hortorium, 1976). Primula originates from the northern hemisphere, China, Europe and the Mediterranean (Griffiths, 1994; Liberty Hyde Bailey Hortorium, 1976; Ward, 1997). Several primula species are produced and used as bedding plants or flowering potted plants (Table 1). The most important species in production include english primrose or acaulis primula (Primula vulgaris synonym P. acaulis) (Blom et al., 1987; Coombes, 1985; Griffiths, 1994), polyanthus, polyantha primrose or hybrid primrose (P. ×polyantha), fairy primrose or baby primrose (P. malacoides), german primrose or poison primrose (P. obconica) and cowslip (P. veris). Chinese primrose (P. sinensis) is also produced in limited numbers and some interest exists in producing drumstick primrose (P. denticulata) as a container plant. Primula is widely produced in Europe as a flowering potted plant for the late winter and early spring market. In the United States, the growing conditions in the Pacific Northwest are particularly well suited for producing primula. In addition to flowering potted plants, primula is used together with other plants in potted arrangements, color bowls and hanging baskets or as a potted plant for outdoor planting in areas with moderate summer temperatures (Goldsberry, 1980). In recent years, sales in the United States have been primarily of bedding plants in areas with mild winters or early spring elsewhere. For garden and bedding uses, english primrose and polyanthus are considered hardy to zone five (Dole and Wilkins, 1999) while fairy primrose, german primrose and chinese primrose cannot withstand frost (Table 1) (Brickell and Zuk, 1996; Karlsson, 1997). Many commercial interests and gardeners are involved in breeding, propagating and growing the numerous primula species and hybrids. Species that are more appropriate for garden plantings include garden auricula (P. ×pubescens, a cross between P. auricula and P. hirsuta), cowslip, julian primrose (P. juliae), siebold primrose (P. sieboldii), and redleaf primrose (P. rosea) (Dole and Wilkins, 1999).

Pollen morphology in Primula sect. Carolinella (Primulaceae) and its taxonomic implications

Pollen morphology in Primula section Carolinella has been investigated for the first time. Seven of the nine species constituting the section were available for study, i. e., P. cardioeides, P. chapaensis, P. intanoensis, P. kwangtungensis, P. kweichouensis, P. partschiana, and P. rugosa, A considerable variation in pollen morphology was found among the investigated species, particularly in number and arrangement of the apertures. Pollen of different species were either tricolpate, tricolporate, trisyncolpate, or polycolpate. Within Primula, the section Carolinella is diagnosed by having calyptrate capsules and leaves with revolute vernation, but the variation in pollen morphology indicates that this group is heterogeneous, and that either polycolpate pollen or a capsular lid has evolved more than once in the genus Primula.

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.

Δ6-Unsaturated fatty acids in species and tissues of the Primulaceae

Abstract The Δ 6 - unsaturated fatty acids γ-linolenic acid (GLA; 18:3Δ 6,9,12 ) and octadecatetraenoic acid (OTA; 18:4Δ 6,9,12,15 ) were present in seed lipids of the tribe Primuleae, but not in other tribes of the Primulaceae. Within the genus Primula both fatty acids were present in seed lipids from 22 species (from 12 sections), with combined levels increasing from 1.1 to 27.4%. High levels of Δ 6 -unsaturated fatty acids were also present in leaves of ten species (from nine sections), but with lower levels generally being present in root lipids. In general, the levels of octadecatetraenoic acid were higher than that of γ-linolenic acid. The results indicate that Δ 6 - unsaturated fatty acids could be used as taxonomic markers within the genus Primula .

Metabolism of D-glycero-D-manno-heptitol, volemitol, in polyanthus. Discovery Of a novel ketose reductase1

Volemitol (D-glycero-D-manno-heptitol, alpha-sedoheptitol) is an unusual seven-carbon sugar alcohol that fulfills several important physiological functions in certain species of the genus Primula. Using the horticultural hybrid polyanthus (Primula x polyantha) as our model plant, we found that volemitol is the major nonstructural carbohydrate in leaves of all stages of development, with concentrations of up to 50 mg/g fresh weight in source leaves (about 25% of the dry weight), followed by sedoheptulose (D-altro-2-heptulose, 36 mg/g fresh weight), and sucrose (4 mg/g fresh weight). Volemitol was shown by the ethylenediaminetetraacetate-exudation technique to be a prominent phloem-mobile carbohydrate. It accounted for about 24% (mol/mol) of the phloem sap carbohydrates, surpassed only by sucrose (63%). Preliminary 14CO2 pulse-chase radiolabeling experiments showed that volemitol was a major photosynthetic product, preceded by the structurally related ketose sedoheptulose. Finally, we present evidence for a novel NADPH-dependent ketose reductase, tentatively called sedoheptulose reductase, in volemitol-containing Primula species, and propose it as responsible for the biosynthesis of volemitol in planta. Using enzyme extracts from polyanthus leaves, we determined that sedoheptulose reductase has a pH optimum between 7.0 and 8.0, a very high substrate specificity, and displays saturable concentration dependence for both sedoheptulose (apparent Km = 21 mM) and NADPH (apparent Km = 0.4 mM). Our results suggest that volemitol is important in certain Primula species as a photosynthetic product, phloem translocate, and storage carbohydrate.

The Genus Primula as a Model for Evolution in the Alaskan Flora

Detailed analysis of evolutionary mechanisms in a single genus can provide insight into the processes shaping a regional flora. The genus Primula (primrose) offers a model for the complex origins of the moder Alaskan flora. The arctic species in this genus represent strong ties to Asia and to other parts of North America, as well as an autochthonous element. Migration routes have been along mountain chains, coastlines, and river systems. Speciation has been facilitated by reproductive specialization, notably distyly with obligate outcrossing, and homostyly with self-fertility. Separation of gene pools, isolation, chance mutations acted upon by selection for reproductive assurance, hybridization, and polyploidy have contributed heavily to speciation. A model for the interrelationship of homostyly and polyploidy is suggested.

Stearidonic acid (18:4ω3) in Primula florindae

Stearidonic acid (18:4ω3), which is reported to be of rare occurrence in the plant kingdom and which is of considerable dietary and pharmaceutical interest has been found in three closely related Primula species. It occurs, together with γ-linolenic acid (3–4% of the seed oil total fatty acids), in significant percentages in Primula florindae (11%), P. sikkimensis (14%) and P. alpicola (14%). 18:4(ω3 may also be of chemotaxonomic interest in the genus Primula, as high levels may be typical for section Sikkimensis. The only commercial plant source of stearidonic acid known so far is the seed oil of Ribes nigrum.

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Primula anvilensis (Primulaceae): A New Species from Northwestern Alaska

Primula anvilensis (Primulaceae: Farinosae) is described as a new species endemic to the Seward Peninsula of western Alaska. It is distinguished by its delicate stature, efarinose den- ticulate leaves, and umbels of small white flowers subtended by plane bracts. Although first col- lected in the early part of this century, it has been confused with several other taxa, including Primula borealis Duby, P. parvifolia Duby, P. tenuis Small, P. chamissonis Busch, P. stricta Hornem., and P. mistassinica Michx. In northwestern North America, many of the representatives of the genus Primula belong to sect. Farinosae Pax (syn. sect. Aleuritia Duby). Taxa belonging to this section have a chromo- some base number of nine, a single umbel of violet or white flowers, and characteristic fari- na-producing glands on vegetative parts. Al- though the genus is well represented in west- ern Alaska (Hulten 1968), past collections from the area have been somewhat rare and geo- graphically limited as collectors had focused upon a few coastal ports due to the lack of road access. An extensive collection of Primula from the area is now available at ALA that indicates it is necessary to reassess the taxonomy of the Alaskan members of the section. Along the west coast of Alaska, the most

Some Functions of Dioecy in Seed Plants

Comments are made on recent publications that emphasize that dioecy in seed plants can be more than just an outcrossing mechanism. It is accepted that "sexual selection" may play an important role in the evolution of dioecy. Circumstantial evidence is presented that when habitat conditions favor outcrossing easily evolved dioecy may be selected. Nevertheless, the disputed suggestion made by me a quarter of a century ago that dioecy appears to have arisen more frequently in hermaphrodite or monoecious taxa that do not have the genetical resources to produce a functional self-incompatibility system is defended, with some indication that this relationship should be examined at the genus level rather than at the level of the family as originally proposed. Disadvantages (to the plants) of dioecy compared to a self-incompatibility system, particularly a monomorphic multiple-allele one, are considered in this light. Distyly is the only incompatibility breeding system that may be expected to give rise sometimes to dioecy (for the flowers are already morphologically halfway to dioecious) although the classic example of distyly, the large genus Primula, shows no sign of dioecy, and some postulated cases of this transition (Bauhinia and Morinda) need to be reexamined. Examples of the apparent evolution of gynodioecy or dioecy after the loss of self-incompatibility are also considered (Armeria, Fragaria, Rubus, and possibly Solanum). It is suggested that all of the "outcrossing" and "sexual selection" hypotheses that have been put forward may have a basis in fact and may even be operative simultaneously.

Hexaploid populations of « Primula palinuri » Petagna in some recently discovered stations from its Thyrrenian range

Summary Plants of Primula palinuri Petagna, collected from some recently discovered stations of the Italian Thyrrenian coast, were found to be exclusively hexaploid (2n = 66). The taxonomic position of this species and its relationships with the other entities of the genus Primula are discussed.

Volemitol in the Genus Primula - Distribution and Significance

Summary The distribution of the heptitol volemitol within the genus Primula has been investigated. About 90 species representing 23 sections of the genus have been included. Volemitol is not a common constituent of all Primula species, but is restricted to a few sections as far as examined, e.g. to all sections of the subgenus Primula . Species which have volemitol contain this compound in all parts of the plant. Highest concentrations are found in the leaves. Volemitol is strongly 14 C-labelled during photosynthetic 14 C0 2 -assimilation. The results are discussed with respect to the chemotaxonomic significance of the pattern of distribution of volemitol and of hamamelitol.

Hamamelose and its derivatives as chemotaxonomic markers in the genus Primula

About 550 species of vascular plants as well as a few mosses were checked for the occurrence of hamamelose, the corresponding alcohol hamamelitol and a galactoside of the latter, clusianose. Hamamelose was found in most of the species investigated. It provides therefore no useful character for chemotaxonomic purposes. Hamamelitol, however, could only be detected in the genus Primula and was therefore more useful. Small amounts of hamamelitol were found in the leaves of species from the subgenera Auganthus, Aleuritia and Auricula but not from Primula and Sphondylia. Clusianose and large amounts of hamamelitol are produced by species of 4 subsections of the section Auricula, but not by species of the subsections Auricula and Erythrodrosum. A taxonomic separation of the two latter from the 4 former subsections is suggested. The taxonomic position of Primula allionii should be reconsidered, since neither clusianose nor hamamelitol could be demonstrated in this species, whereas the other species of the subsection Rhopsidium do contain these carbohydrates.

Comparative biochemistry of the flavonoids—VII : Correlations between flavonoid pigmentation and systematics in the family primulaceae

A survey of the flavonoids and other phenolics in leaf and flower of a hundred species, representing 18 of the 25 genera, of the Primulaceae has shown that the richest variation in pigment structures occurs in the genus Primula. Thus, the rare 7- O-methylated anthocyanin hirsutin is confined to this genus (in 30 of 41 cyanic species) and occurs in all subgenera except Auganthus, where it is replaced by malvin or malvidin 3-glucoside as the principal petal pigment. The related rosinin, earlier detected in P. rosea petals, has now been found in P. clarkei in the same section. Peonidin is only found as a principal pigment in the crimson calyces of P. viali. Cyanin and other cyanidin glycosides are confined to the petals of P. chungensis, P. aurantiaca, P. cockburniana (all section Candelabra) and P. warshenewskiana (section Farinosae). Delphinidin occurs as the principal petal pigment only in P. ioessa. Other genera of the family ( Cortusa, Dodecatheon, Cyclamen, Soldanella) have anthocyanins based on malvidin, delphinidin or cyanidin. The yellow flavonol in petals of P. vulgaris, P. veris and P. elatior (all section Vernales) previously reported as quercetagetin has now been found to be the 8-hydroxy isomer, gossypetin. Gossypetin also occurs in yellow petals of four species of the section Sikkimenses, and in one of these, P. alpicola, it is accompanied by herbacetin. Gossypetin has also been detected in two closely related genera Dionysia and Douglasia but yellow flower colour elsewhere in the family (e.g. Lysimachia) is probably carotenoid. The simple 3′,4′-dihydroxyflavone, identified in this family for the first time as a leaf glucoside, is of biogenetic interest in relation to the production of flavone in the leaf farina of Primula. It is also of systematic interest, since it occurs widely in Primula (in 39 of 55 species) and in three related genera ( Cortusa, Dodecatheon and Dionysia) in the subfamily Primuleae but was not otherwise detected in the family. Other new phenols of taxonomic interest in Primula include a new trihydroxyflavone and a substance, chionanthin, with a distinctive pink fluorescence in u.v. light, which is possibly related to 7-hydroxyflavone. Leucocyanidin, leucodelphinidin, kaempferol and quercetin occur throughout the family. By contrast, myricetin is uncommon (in 4 Primula and in 2 Lysimachia spp.) and the flavones apigenin and luteolin have only been detected so far in Soldanella, presumably a phyletically advanced taxon. Kaempferol and quercetin occur in Primula leaf and petal in combination with a range of sugars and the distribution of some of these glycosides is clearly related to classification at the subgeneric level. The very common kaempferol 3-gentiotrioside, thus, is rare in section Candelabra and absent from Sikkimenses (both subgenus Aleurita), being largely replaced by rutin, which in turn is rare in the subgenus Auganthus and absent from the subgenus Craibia.

Additions and Corrections to the Genus Primula (Up to and Including 1949)

(1949). Additions and Corrections to the Genus Primula (Up to and Including 1949) Transactions of the Botanical Society of Edinburgh: Vol. 35, No. 2, pp. 180-202.

The Genus Primula: Section Malvacea Balf. fil.

The Genus Primula: Section Malvacea Balf. fil.

The Genus Primula: Section Amethystina

The Genus Primula: Section Amethystina