Pale Flowers Research Articles

Review of the genus <i>Xenoscapa</i> (Iridaceae: Crocoideae), including <i>X. grandiflora</i>, a new species from southern Namibia

The small genus Xenoscapa (Goldblatt) Goldblatt J.C.Manning, endemic to the southern African winter rainfall region, is reviewed. The new species X. grandiflora is described from the deeply dissected southern part of the Huib Hoch Plateau in southern Namibia. It differs from the two known species in the genus in its significantly larger, pale lilac flowers. Full descriptions and accounts of all three known species are provided, with distribution maps and illustrations.

Where have all the blue flowers gone: pollinator responses and selection on flower colour in New ZealandWahlenbergia albomarginata

Although pollinators are thought to select on flower colour, few studies have experimentally decoupled effects of colour from correlated traits on pollinator visitation and pollen transfer. We combined selection analysis and phenotypic manipulations to measure the effect of petal colour on visitation and pollen export at two spatial scales in Wahlenbergia albomarginata. This species is representative of many New Zealand alpine herbs that have secondarily evolved white or pale flowers. The major pollinators, solitary bees, exerted phenotypic selection on flower size but not colour, quantified by bee vision. When presented with manipulated flowers, bees visited flowers painted blue to resemble a congener over white flowers in large, but not small, experimental arrays. Pollen export was higher for blue flowers in large arrays. Pollinator preference does not explain the pale colouration of W.albomarginata, as commonly hypothesized. Absence of bright blue could be driven instead by indirect selection of correlated characters.

Distinguishing colour variants of <i>Serapias perez-chiscanoi</i> (Orchidaceae) from related taxa on the Iberian Peninsula

Serapias perez-chiscanoi has a stable and uniform appearance with green flowers. Throughout its distribution area, however, plants have been found with deviant pink to red flowers that show similarities with other taxa that are occasionally pale flowered. S. perez-chiscanoi is easy to differentiate from S. cordigera subsp. cordigera by the colour of the flowers (S. cordigera subsp. cordigera has red to purple flowers) and the fact that the hypochile dimensions of S. perez-chiscanoi are significantly smaller. It is, however, more difficult to distinguish it from individuals of S. cordigera subsp. gentilii with pale flowers, which occur frequently. The two taxa differ in colour pattern and floral dimensions, especially the hypochile length, which is shorter in S. perez-chiscanoi. Pale-flowered individuals of another species, S. parviflora, are easily distinguished by their significantly smaller flowers. S. perez-chiscanoi occurs in Spain in the autonomous regions of Extremadura and Castilla-La Mancha and in Portugal, S. cordigera subsp. gentilii seems to occur along the coastal regions of SW Portugal, while S. cordigera subsp. cordigera and S. parviflora are distributed throughout the Iberian Peninsula.

MATE2 Mediates Vacuolar Sequestration of Flavonoid Glycosides and Glycoside Malonates inMedicago truncatula

The majority of flavonoids, such as anthocyanins, proanthocyanidins, and isoflavones, are stored in the central vacuole, but the molecular basis of flavonoid transport is still poorly understood. Here, we report the functional characterization of a multidrug and toxin extrusion transporter (MATE2), from Medicago truncatula. MATE 2 is expressed primarily in leaves and flowers. Despite its high similarity to the epicatechin 3'-O-glucoside transporter MATE1, MATE2 cannot efficiently transport proanthocyanidin precursors. In contrast, MATE2 shows higher transport capacity for anthocyanins and lower efficiency for other flavonoid glycosides. Three malonyltransferases that are coexpressed with MATE2 were identified. The malonylated flavonoid glucosides generated by these malonyltransferases are more efficiently taken up into MATE2-containing membrane vesicles than are the parent glycosides. Malonylation increases both the affinity and transport efficiency of flavonoid glucosides for uptake by MATE2. Genetic loss of MATE2 function leads to the disappearance of leaf anthocyanin pigmentation and pale flower color as a result of drastic decreases in the levels of various flavonoids. However, some flavonoid glycoside malonates accumulate to higher levels in MATE2 knockouts than in wild-type controls. Deletion of MATE2 increases seed proanthocyanidin biosynthesis, presumably via redirection of metabolic flux from anthocyanin storage.

Excision of an Active CACTA-Like Transposable Element From DFR2 Causes Variegated Flowers in Soybean [Glycine max (L.) Merr.

Active endogenous transposable elements, useful tools for gene isolation, have not been reported from any legume species. An active transposable element was suggested to reside in the W4 locus that governs flower color in soybean. Through biochemical and molecular analyses of several revertants of the w4-m allele, we have shown that the W4 locus encodes dihydroflavonol-4-reductase 2 (DFR2). w4-m has arisen through insertion of Tgm9, a 20,548-bp CACTA-like transposable element, into the second intron of DFR2. Tgm9 showed high nucleic acid sequence identity to Tgmt*. Its 5' and 3' terminal inverted repeats start with conserved CACTA sequence. The 3' subterminal region is highly repetitive. Tgm9 carries TNP1- and TNP2-like transposase genes that are expressed in the mutable line, T322 (w4-m). The element excises at a high frequency from both somatic and germinal tissues. Following excision, reinsertions of Tgm9 into the DFR2 promoter generated novel stable alleles, w4-dp (dilute purple flowers) and w4-p (pale flowers). We hypothesize that the element is fractured during transposition, and truncated versions of the element in new insertion sites cause stable mutations. The highly active endogenous transposon, Tgm9, should facilitate genomics studies specifically that relate to legume biology.

Systematics of the southern African genus Ixia (Iridaceae). 1. The <i>I.</i> <i>rapunculoides</i> complex

Field and laboratory investigation of the six varieties of Ixia rapunculoides Delile (recognized in the current revisions and flora accounts of this southern African genus of some 65 species) show that a revised taxonomy better reflects the biology of the complex. The complex is defined by the funnel-shaped perianth tube, filaments fully and anthers partly included in the perianth tube. Our conclusions indicate that I. rapunculoides (currently var. rapunculoides) is restricted to the western Karoo and has broad, leathery leaves, a short perianth tube, mostly 5.5-8.0 mm long, and half nodding blue-mauve flowers. Plants currently referred to I. rapunculoides var. flaccida G.J.Lewis, include four sets of populations that we regard as two separate species. These are: I. flaccida with small, short-tubed white- or pale blue-flushed flowers, sofl-textured leaves and corms with basal cormlets from the Olifants River Valley and nearby; and I. sobolifera from the Western and Little Karoo, which has linear leaves, nodding spikes and flowers and corms with stolons. We divide I. sobolifera into three subspecies: subsp. carnea with pink flowers, is restricted to the Bokkeveld Plateau and nearby; subsp sobolifera with slate-blue flowers occurs in the Klein Roggeveld and nearby; and subsp albiflora with strongly scented white flowers occurs in the central Little Karoo. The taxon called I. rapunculoides var. namaquana (L.Bolus) G.J.Lewis, defined by a longer perianth tube, mostly 13-16 mm long, horizontally oriented, white, pale lilac or pink flowers and few-flowered lateral branchlets. is treated as I. namaquana, first described by H.M.L. Bolus in 1931. Plants referred to this taxon from south of its range at Hex River pass and nearby, however, have fully included anthers, a longer perianth tube. 16-20 mm. and ascending purple-pink flowers with a white cup and are referred to the new I. oxalidiflora. Two more varieties, I. rapunculoides var. subpendula G.J.Lewis and var. rigida sensu G.J.Lewis, which have upright flowers and distinctively branched stems are treated here as I. divaricata and I. contorta. Plants in the past included in var. rapunculoides from the Klein Roggeveld, south of the range of typical I. rapunculoides, have a longer perianth tube. 10-14 mm long, and attenuate, slightly lacerate. 5-veined. dry. rust-tipped bracts and comprise the new I. lacerata In addition, plants from streambeds in the Roggeveld that have large, white flowers, are not included in current accounts of the genus, and also represent a novel taxon, I. rivulicola. Lastly, I. rapunculoides var. robusta G.J.Lewis, the range of which falls entirely within that of var. rapunculoides and is usually sympatric with it. has pink flowers of similar structure, but four or five leaves and deep-seated corms with a collar of coarse fibres around the stem base. We raise this plant to species rank as I. robusta

Three cryptic new species of <i>Aristea</i> (Iridaceae) from southern Africa

Field work in southern Africa over the past several years has resulted in the discovery of three new species of the sub- Saharan African and Madagascan genus Aristea Aiton, which now comprises some 53 species. Aristea has a pronounced centre in southern Africa and a centre of diversity in the winter rainfall zone of the subcontinent, where all three new species occur, one extending eastward into the adjacent southern edge of the summer rainfall zone. All three novelties have been collected in the past but were confused with related species. A elliptica (subgenus Eucapsulares), confused in the past with A. pusilla (Thunb.) Ker Gawl., has a more robust habit, usually with 4 or 5 flower clusters per flowering stem, pale blue flowers, smooth ellipsoid seeds with flattened surface cells, and pollen shed as monads, whereas A. pusilla usually has 1-3 flower clusters per flowering stem, dark blue flowers, pollen shed as tetrads, and globose seeds with faint foveate sculpturing and colliculate surface cells. A. nana (also subgenus Eucapsulares), known from few collections, and also confused with A. pusilla or A. anceps Eckl. ex Klatt. has the unbranched and leafless flowering stem of the latter but has large green floral spathes, flowers borne on long pedicels, and lacks a leaf subtending the single terminal flower cluster in contrast to nearly sessile flowers in A. pusilla and A. anceps, and in the latter, dry, rusty spathes. A. cistiflora (subgenus Pseudaristea) closely resembles A. teretifoha Goldblatt J.C.Manning but has linear to narrowly sword-shaped leaves and ± secund flowers with the outer tepals only slightly smaller than the inner and with small, dark brown markings at the bases of all the tepals. In contrast, A. teretifolia has narrower, sometimes terete leaves and flowers held upright with the outer tepals notice-ably smaller than the inner and bearing dark markings covering the lower half, whereas the inner tepals are unmarked.

Genetic analysis and molecular mapping of a pale flower allele at theW4locus in soybean

In soybean (Glycine max (L.) Merr.), the w4-mutable line that harbors the w4-m allele was identified in 1983. It was proposed that this line contained an autonomous transposable element at the W4 locus, which is a major locus controlling the biosynthesis of anthocyanin. The w4-m allele can revert to the W4 allele that produces the wild-type phenotype, or sometimes to other alleles that produce intermediate phenotypes. Mutant plants that produce pale flowers were identified among the progeny of a single germinal revertant event from the w4-mutable line. Through genetic analysis, we established that the pale-flower mutation was conditioned by a new allele (w4-p) at the W4 locus. The w4-p allele is dominant to the w4 allele but recessive to the W4 allele, and the w1 allele has an epistatic effect on the w4-p allele. The pale-mutant line (w4-pw4-p) was designated as Genetic Type Collection number T369. An F2 mapping population derived from the cross of Minsoy (W4W4) x T369 (w4-pw4-p) was used to map the W4/w4-p locus, using simple sequence repeat (SSR) markers. The W4 locus was located at one end of molecular linkage group D2, 2.3 cM from the SSR marker Satt386 and close to the nearby telomere.

A new species, Herbertia crosae (Iridaceae), from Uruguay

Abstract Roitman, G. G. (Catedra de Jardineria. Facultad de Agronomia, Universidad de Buenos Aires, Av. San Martin 4453. 1417. Buenos Aires, Argentina; roitman@mail.agro.uba.ar) & A. Castillo (Jardin Botanico de Ezeiza, Jujuy 1037, 1804, Ezeiza, Prov. de Buenos Aires, Argentina; ezeizabotgard@hotmail.com). A new species, Herbertia crosae (Iridaceae), from Uruguay. Brittonia 56: 361–364. 2004.—Herbertia crosae (Iridaceae) is described from the stony grasslands of northwestern Uruguay. The new species resembles Herbertia lahue but can be easily distinguished by the narrower leaves, slender habit, the smaller pale lilac flowers, the presence of yellow spots at the base of the tepals, the red, adpressed hairs along the filament column, the presence of filaments free at the apex, the channeled style arm, the recurved secondary divisions of the style arm, and the smaller fruits. A key to the species of the genus is provided in which five species are now recognized.

A new species of Orobanche (Orobanchaceae) from south-eastern Spain

A new species, Orobanche portoilicitana A. Pujadas & M. B. Crespo (sect. Trionychon Wallr.) is described from the south-eastern coast of the Iberian Peninsula. This species inhabits coastal sand dunes where it is parasitic on Centaurea species. It is characterized by its dense, many-flowered inflorescences, which bear usually erect, pale bluish flowers with long apiculate anthers. Several morphological features relate the new species to O. olbiensis (Coss.) Nyman, a plant known only from southern France, with which it had been misidentified. A complete description and the diagnostic characters allowing differentiation from other taxa in the section are reported. Further data on ecology and conservation status are also presented. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society, 2004, 146, 97–102.

Insect colour preference compared to flower colours in the Australian Alps

An apparent predominance of plant taxa with pale flowers in the alpine floras of Australia and New Zealand may be due to the prevalence of insects, such as flies, that prefer pale colours and the absence of other types of potential pollinators that are attracted to bright colours such as social bees and birds. In this study, the diversity of flower colours, and the preference of insects for different colours were examined for the largest contiguous alpine area in Australia, around Mt Kosciuszko. Out of an alpine flora of 204 taxa, 127 species were found to have large showy flowers. The most common flower colour among these taxa was white (53.5%), then yellow (21.3%), followed by pink (6.3%), and cream (6.3%). Only a handful of taxa had red, blue, brown, green, orange or purple flowers. When the colour preference of insects was tested using five different coloured traps (white, yellow, orange, red and purple), the most successful traps were white then yellow, with these two colours accounting for 66% of all individual insects collected. Diptera were the most common insects caught (576 insects greater than 4 mm in length, 31 morphotaxa) showing an apparent preference for white and yellow coloured traps over others. Therefore, the results add some support to the proposition that the ‘white’ flora of the Australian Alps may be associated with the colour preference of flies, which have previously been found to be the most common type of pollinators in the Kosciuszko alpine zone.

Daubenya alba (Hyacinthaceae, tribe Massonieae), a new species from the Roggeveld, Northern Cape Province

Daubenya alba A.M. van der Merwe, from the edge of the Roggeveld escarpment in the Northern Cape Province, is described as a new species. It resembles D. capensis (Schltr.) A.M. van der Merwe & J.C. Manning in leaf shape, floral structure and the presence of a staminal tube, but is distinguished by its delicate white to pale lilac flowers and lack of a staminal disc.

The rise and fall of plant species: a population biologist's perspective

The rise and fall of plant species: a population biologist's perspective

Platanthera lacera × leucophaea, a new cryptic natural hybrid, and a key to northeastern North American fringed-orchids

To evaluate the putative hybrid origin of fringed-orchids from York County, Ontario, morphological attributes of hybrid flowers were evaluated with respect to both a random sample of herbarium specimens and populations from the hybrid location. The putative hybrids were intermediate in spur length, petal width, and vertical distance across opening to the spur as well as in eight other quantitative characters. The hybrid is named Platanthera ×hollandiae Catling & Brownell (= Platanthera lacera (Michx.) G. Don × Platanthera leucophaea (Nutt.) Lindl.). With pale greenish-white flowers, partly reflexed lateral sepals, and a horizontally linear spur opening, the putative hybrid plants resemble P. lacera but can be readily distinguished by their relatively long spurs, relatively broad lateral petals, and ovoid instead of strap-shaped viscidium. A key including characteristics of the column is included that allows the separation of all northeastern North American fringed-orchids and their known natural hybrids.Key words: orchid, hybrid, Platanthera lacera, Platanthera leucophaea, Canada, Ontario.

Mapping morphological genes relative to molecular markers in lettuce (Lactuca sativa L.)

Two F2 populations were generated by crossing morphologically diverse genetic stocks in order to map 10 morphological traits relative to polymerase chain reaction-based molecular markers (RAPDs). Using one segregating population generated from crossing the experimental line, ‘dwarf-2’, with the butterhead cultivar, ‘Saffier’, the dwarf phenotype conditioned by the dwf2 locus was mapped using bulked segregation analysis to within 38 cM of the Adh3 locus. Using the second segregating population generated by crossing two experimental lines, 87-25-1M × 87-109M, nine traits [white seed (w), brown seed (br), salmon flower colour (sa), pale yellow flower colour (pa), virescent juvenile leaf colour (vi), plump involucre (pl), yellow seed (y), one of two complementary genes for anthocyanin expression (C or G) and anthocyanin spotting (Rs)] were linked to RAPD loci, but only six of them could be placed on an existing genetic map of lettuce generated by analysis of cv. ‘Calmar’ × cv. ‘Kordaat’. A tenth trait, golden yellow (gy), remained unlinked. Approximately a third of the RAPD markers analysed segregated in both the 87-25-1M × 87-1090M and ‘Calmar’ × ‘Kordaat’ populations. In the genomic regions with multiple segregating loci in common, their relative orders and distances were mostly conserved. In one instance, linkage detected in the present study consolidated two separate groups on the earlier genetic map.

Inheritance of Pale Flower, Calyx Spotting, and Glandular Pubescence in Mimulus guttatus M. platycalyx Progenies

Despite growing interest in the Mimulus guttatus complex as a model for evolutionary studies of wild herbaceous plants, few examples of major genes controlling morphological variation have been described. We examined the inheritance of several candidate traits in experimental crosses between the closely related species M. guttatus and M. platycalyx. A pale flower color morph was found to be controlled by a single recessive gene, designated P/p. Despite bimodal distribution in segregating populations, calyx spotting and glandular pubescence failed to consistently fit Mendelian ratios. However, analysis of the pattern of variation within F3 families indicated the presence of a single to few major genes or leading factors responsible for segregation variation for both traits. There was no evidence for linkage among loci controlling these traits.

Allelic interactions at the nivea locus of Antirrhinum.

Most null alleles at the nivea (niv) locus are recessive to Niv+ and, when homozygous, give white flowers rather than the red of the wild type. In contrast, the niv-571 allele is semidominant; although it gives white flowers when homozygous, very pale flowers result when this allele is heterozygous with NIV+. We showed that in heterozygotes, niv-571 acts in trans to inhibit expression of its Niv+ homology 25-fold to 50-fold. The inhibition is reversible after meiosis and partially reversible somatically. The niv-571 allele carries a transposable element Tam3 insertion and three truncated copies of the niv gene, one copy being in inverse orientation. Analysis of two further niv alleles, niv-572 and niv-527, showed that excision of Tam3 from niv-571 does not affect the ability of the allele to repress Niv+ and that one truncated niv copy alone is insufficient to confer semidominance. The detailed structures of various semidominant niv alleles suggest that their effects in trans are not readily explained by production of antisense RNA but are more easily reconciled with a direct recognition/interaction between homologous genes, reminiscent of cosuppression and transvection phenomena described in other systems.

The genus Petopentia (Periplocaceae)

A taxonomic–morphological treatment of the monotypic genus Petopentia Bullock is presented. Petopentia natalensis (Schltr.) Bullock occurs in the subtropical southern African forests of Natal and Transkei. It is a liana with very characteristic hemispherical above-ground root tubers, elliptic and parallel-veined leaves, pale green-yellowish flowers which have terete corona lobes, and unusual linear- or T-shaped pollen tetrads. The flowers of P. natalensis are basically similar to those of Periploca Decne., Tacazzea Decne., Sarcorrhiza Bullock, Schlechterella K. Schum. and Zacateza Bullock, all tropical African genera. Zacateza and Periploca are probably the closest living relatives of Petopentia.

W4‐Mutable line in soybean

AbstractAn unstable mutation for anthocyanin pigmentation in soybean (Giycine max [L.] Merr.) was identified in 1983. The mutability is conditioned by an allele at the w4 locus that is recessive to wild type. The population containing the mutable allele is known as the w4‐mutable line. Most plants in the line have chimeric flowers with purple sectors on a near‐white background. The mutable allele yields germinal revertants at a rate that varies from 5 to 10% per generation, and the revertant alleles are stable. Approximately 1% of the progenies derived from germinal revertant plants contain mutations at other loci These features, as well as the occurrence of pale flower phenotypes and changes of state, suggest that a transposable element system is producing the unstable phenotype.Several new mutants were isolated in an experiment designed to tag loci. The first three chlorophyll‐deficient mutants found (CD‐1, CD‐2, and CD‐3) are inherited as single‐gene recessives. Each of the mutants lacks the same two mitochondrial malate dehydrogenase (MDH) bands. No recombination has been detected between the MDH phenotype and the chlorophyll‐deficient phenotype. Genetic data indicate that the three mutants are allelic, and additional evidence suggests that each of the CD mutants is the result of a deletion. In the CD‐1, CD‐2, and CD‐3 mutants, the deletions result in the silencing of an MDH locus, atypical chloroplast development, and an altered chlorophyll composition. Additional mutants for root necrosis, partial and near sterility, chlorophyll deficiency, and flower color isolated from the transposon tagging study have provided material for future research.

The Homeria Species of Thunberg's Herbarium

Thunberg's South African collections contain the type material for four species which conform to current concepts of Homeria. A detailed examination of the type material in the Thunberg Herbarium has resulted in selection of lectotypes for three of these species, where more than one sheet of a species was present. Homeria collina (Thunb.) Vent and H. umbellata (Thunb.) Lewis remain as presently interpreted. However, the name polyanthos L.f., as currently understood is misapplied and is an earlier name for H. lilacina L. Bol. The species at present called M. polyanthos now becomes M. bipartita L. Bol. The type of the fourth species, M. crispa, is incomplete, but it is very likely that it is simply a crisped-leafed form of the widespread Karoo species H. rogersii L. Bol. for which it is an earlier synonym. No new combinations in Homeria are made here. The genus is currently under investigation, and the definition of Homeria and the related is being revised. Homeria is a genus of some 30 species of Iridaceae-Irideae, endemic in southern Africa. Species are concentrated in the Cape Region of South Africa, and, where they occur, are generally very common plants. Strangely, Thunberg's collection from the Cape, now housed in the herbarium of the Institute for Systematic Botany, University of Uppsala, Sweden, has few specimens of the genus, and from these only four species were described. This is most likely because Thunberg thought there were only a few species where today we recognize many, and so he collected no more specimens once he felt he had gathered the basic types. Thunberg, and as well the younger Linnaeus, who worked on Thunberg's collections, considered Homeria indistinguishable from genera such as Aristea, Ferraria, Tigridia, and Bobartia, and they placed species of all these genera in Moraea. True species of they regarded as Iris, and Thunberg collected a large number of species of true Moraea, a very variable genus at the Cape. Of the many species of Moraea which Linnaeus fil. and Thunberg described, the following four are Homeria-like. The first is M. polyanthos L.f. (1781); followed by M. collina, M. umbellata and M. crispa, all described by Thunberg (1787). In modern times, N. E. Brown (1928) examined Thunberg's Iridaceae, including the few Homeria species. I have recently examined the specimens in question, not always agreeing with Brown's conclusions. The sheets are listed below by species with the numbers assigned to them on the microfiche of Thunberg's herbarium. 1. collina Thunb. 1209 Specimen has a large pale flower; anthers 7 mm long, slightly diverging; tepals ca. 40 mm long, 15 mm wide; ovary 12 mm long. A good match for the common Cape Peninsula species now known as H. collina (Thunb.) Salisb. This specimen is the lectotype.