White Sepals Research Articles

New species of <i>Maxillaria</i> (Maxillariinae) from the northern Andes and a new synonym of <i>Maxillaria floribunda</i>

Maxillaria andina, a new orchid species from high-Andean ecosystems of southwestern Colombia and northern Ecuador, is described. The new species is distinguished by having long and narrowly linear white sepals and petals with revolute margins, lip with mucronate epichile, and callus without hairs or trichomes. Distinguishing characters are provided to differentiate it from morphologically similar species, along with ecological and taxonomical notes. Additionally, Maxillaria sibundoyensis is synonymized with Maxillaria floribunda.

Molecular mechanism of different flower color formation of Cymbidium ensifolium.

Cymbidium ensifolium is one of the national orchids in China, which has high ornamental value with changeable flower colors. To understand the formation mechanism of different flower colors of C. ensifolium, this research conducted transcriptome and metabolome analyses on four different colored sepals of C. ensifolium. Metabolome analysis detected 204 flavonoid metabolites, including 17 polyphenols, 27 anthocyanins, 75 flavones, 34 flavonols, 25 flavonoids, 18 flavanones, and 8 isoflavones. Among them, purple-red and red sepals contain a lot of anthocyanins, including cyanidin, pelargonin, and paeoniflorin, while yellow-green and white sepals have less anthocyanins detected, and their metabolites are mainly flavonols, flavanones and flavonoids. Transcriptome sequencing analysis showed that the expression levels of the anthocyanin biosynthetic enzyme genes in red and purple-red sepals were significantly higher than those in white and yellow-green sepals of C. ensifolium. The experimental results showed that CeF3'H2, CeDFR, CeANS, CeF3H and CeUFGT1 may be the key genes involved in anthocyanin production in C. ensifolium sepals, and CeMYB104 has been proved to play an important role in the flower color formation of C. ensifolium. The results of transformation showed that the CeMYB104 is involved in the synthesis of anthocyanins and can form a purple-red color in the white perianth of Phalaenopsis. These findings provide a theoretical reference to understand the formation mechanism of flower color in C. ensifolium.

Taxonomic revision of the genus Spiranthes (Orchidaceae) in Taiwan

The taxonomy of Spiranthes is highly challenging due to its phenotypic plasticity, morphological convergence, and hybridization. This paper presents a re-evaluation of the genus Spiranthes (Orchidaceae) in Taiwan, with special reference to the taxonomic identity of S. suishaensis that has often been considered the earlier name of S. nivea or S. hongkongensis. Nonetheless, the floral dissection of the type specimen revealed that S. suishaensis has a well-developed rostellum that separates the stigma and pollinarium of each flower, in contrast to autogamous taxa such as S. nivea and S. hongkongensis. Given the morphological evidence and that only S. sinensis was collected in the S. suishaensis type locality, we concluded that S. suishaensis is neither an earlier name for S. nivea nor S. hongkongensis but a synonym of S. sinensis. During morphological comparisons of S. suishaensis with other taxa of S. sinensis complex, we also found that the taxon illegitimately described as “S. minutiflora” could be treated as a variant of S. nivea. Given that it is distinguishable from S. nivea var. nivea by its more densely pubescent rachis and ovaries (vs. sparsely pubescent rachis and ovaries), narrower sepals with white tinged with pink or purple at apex (vs. wider and entirely white sepals), and papillose labellum disc (vs. almost glabrous labellum disc), we described it as a new variety of S. nivea, which we propose to name S. nivea var. papillata T.C. Hsu & Suetsugu. Consequently, we concluded that three species (S. sinensis, S. hongkongensis, and S. nivea [including var. nivea and var. papillata]) and one hybrid, S. australis × S. sinensis, occur in Taiwan.

Floral Morphology and Chromosome Characteristics of Bamboo Orchid from Menoreh Hills, Kulonprogo

Purpose: One of the most common orchids in Menoreh Hills, Kulonprogo is bamboo orchids (Arundina). This genus has only one species but has a wide variety of flower phenotypic that spreads around the world. The aims of this research were to characterize the flower morphology and chromosome content of bamboo orchids from Menoreh, related to their taxonomic status. Research Method: Observation of morphological characters was carried out to assist the identification process of the bamboo orchid species. The squashing method is used in the preparation of bamboo orchid chromosomes. The results were analyzed with Image Raster 3.0, Corel Draw 11 and Ms. Excel 2010. Findings: Bamboo orchid from Menoreh, Kulonprogo is a flower with white sepals and petals, the tips of sepals are yellowish brown. Labellum is white, with a thin purple stripe on the edges, and the base is yellow. Chromosomes number 2n = 20, with the formula karyotype 2n = 2x = 20 = 16m + 4sm. Chromosomes’ absolute length is 0.55-1.64 μm and relative lengths 0.57-1.615 μm. Based on morphological characters, Menoreh's bamboo orchid has similarities with A. graminifolia, whereas based on chromosomes number and karyotype formula, it is different. Limitations: There are bamboo orchids with a wide variety of flowers around world. However, the sample collection is only limited to bamboo orchid in Purwosari village, Kulonprogo. Value: Menoreh's bamboo orchid has a potential to be a new variant from the A. graminifolia population, based on the differences in morphological and chromosomal characters.

Two new species of Octomeria (Pleurothallidinae) from Cordillera del Cóndor, Zamora Chichinpe, Ecuador

Two new species of orchids, Octomeria pacii, and O. panguiensis are described and illustrated from Cordillera del Cóndor, Ecuador; likewise, information is provided on their distribution, habitat, and conservation status. These species differ from other species in the genus by their floral and vegetative characteristics and their apparent reproductive strategy of cleistogamy. Octomeria pacii is similar to Octomeria deceptrix, but differs in the caespitose habit, the ramicauls compressed along their entire length, the narrowly elliptical leaves, the autogamous flowers, the translucent white sepals suffused with magenta and the obovate, white lip, marked with magenta. Octomeria panguiensisis similar to O. werneri, but differs by the larger, shortly repent plants with lanceolate leaves, the cleistogamous flowers, the translucent white-colored sepals, the 5-veined lateral sepals and the oblong-trilobed lip with the apical lobe tridentate
 Keywords: self-compatibility, self-pollination, cleistogamy, Octomeria deceptrix, Octomeria werneri

Paphiopedilum erythroanthum, a new species of slipper orchid (Cypripedioideae, Orchidaceae) from China based on morphological and molecular data

A new species of Paphiopedilum (Orchidaceae) from Yunnan, China is described and illustrated based on examining morphological and molecular evidence. Morphological comparisons indicate that the new species P. erythroanthum is somewhat similar to P. henryanum, from which it differs by its shorter scape, larger and purple-red flower without purple spots, an obovate dorsal sepal, narrowly oblong petals with recurved apex and a cordate staminode. Molecular analyses of combined nuclear and plastid datasets (ITS and matK) indicate that P. erythroanthum is sister to P. notatisepalum, which has leaves with large yellow spots, a shorter scape, larger flower, white sepals and petals with large purple spots. The morphological and molecular evidence support the hypothesis that P. erythroanthum is a new species.

Phylogeny and genetic variation in the genus Eranthis using nrITS and cpIS single nucleotide polymorphisms

The relationships among species in the genus Eranthis Salisb. were investigated using single nucleotide polymorphisms (SNPs) of the nuclear DNA internal transcribed spacer 1, 2 region (nrITS) and the chloroplast trnL-trnF interspacer region (cpIS). Phylogenetic relationships based on the nrITS and cpIS were inferred with posterior probabilities with STRUCTURE analysis and the neighbor-joining method. Two major clades from nrITS and cpIS were consistent with species with yellow sepals in E. hyemalis, E. cilicica, E. longistipitata and the hybrid E. ×tubergenii; and white sepals in E. sibirica, E. longituba, E. albiflora, E. stellata, E. pungdoensis, E. byunsanensis, and E. pinnatifida. The phylogenetic tree of nrITS formed more subclades than the tree of cpIS, which suggested that nrITS SNPs are useful molecular markers for phylogenetic studies in the genus Eranthis. Only the SNPs of cpIS in E. pungdoensis accessions had a deletion at positions 259–420, and the posterior probability values (PPVs) assigned E. pungdoensis to population 4, which suggested that E. pungdoensis is different from E. byunsanensis. Therefore, E. byunsanensis and E. pungdoensis are considered to be true-to-type based on q-values because the PPVs were greater than 0.9 in both species based on the STRUCTURE analysis of nrITS SNPs. Significant genetic variation in E. stellata collected in Goesan-kun and Mt. Mugap, Korea indicated a potential gene flow among closely related E. byunsanensis, E. pinnatifida, E. sibirica, and E. stellata that could be due to geographic proximity in their distributions. E. stellata from Mt. Mugap showed mixed PPVs for E. stellata and E. byunsanensis, therefore, E. byunsanensis might be a possible hybrid origin for E. stellata collected from Goesan-kun and Mt. Mugap.

Ectopic expression of the PISTILLATA homologous MdPI inhibits fruit tissue growth and changes fruit shape in apple.

Fruit shape represents a key trait that consumers use to identify and select preferred cultivars, and although the manipulation of this trait is an opportunity to create novel, differentiated products, the molecular mechanisms regulating fruit shape are poorly understood in tree fruits. In this study, we have shown that ectopic expression of Malus domestica PISTILLATA (MdPI), the apple ortholog of the floral organ identity gene PISTILLATA (PI), regulates apple fruit tissue growth and shape. MdPI is a single‐copy gene, and its expression is high during flower development but barely detectable soon after pollination. Transgenic apple plants with ectopic expression of MdPI produced flowers with white sepals and a conversion of sepals to petals. Interestingly, these plants produced distinctly flattened fruit as a consequence of reduced cell growth at the basipetal position of the fruit. These altered sepal and fruit phenotypes have not been observed in studies using Arabidopsis. This study using apple has advanced our understanding of PI functions outside the control of petal and stamen identity and provided molecular genetic information useful for manipulating fruit tissue growth and fruit shape.

Paphiopedilum notatisepalum, a new species of slipper orchid (Cypripedioideae, Orchidaceae) from China based on morphological and DNA evidence

A new species of Paphiopedilum (Orchidaceae) from Yunnan, China, is described and illustrated based on morphological and molecular evidence. Morphological comparisons indicate that the new species P. notatisepalum is highly similar to P. henryanum, from which it differs by its leaves with large yellow spots, shorter scape, larger flower, ovate, white sepals and petals that are pale purple-red with large purple spots and yellow-white margins. Molecular analyses of combined nuclear and plastid datasets (nrITS and matK) indicate that P. notatisepalum is sister to P. barbigerum, which has a green leaves and pale yellow-green sepals and petals. The morphological and molecular evidence support the hypothesis that P. notatisepalum is a new species.

A New Brachionidium (Orchidaceae: Pleurothallidinae) from the First Botanical Expedition to the Volc�n Cacho Negro, Costa Rica

Abstract A new species of Brachionidium from Costa Rica is described and illustrated. Brachionidium cornu-nigricum, from the Volcan Cacho Negro, a remote, previously unexplored location in Costa Rica, is most similar to B. filamentosum. It differs in the white sepals, short-acuminate sepals and petals up to 1 cm long, the triangular, unlobed lip, the oblong glabrous callus provided with two small basal lobes, and the eight pollinia.

Pollinator-mediated selection on nectary depth in Urophysa (Ranunculaceae)

Pollinator-mediated selection has been considered to be one of major factors that shapes the evolution of flowers by matching flowers to their pollinators on traits associated with attraction of pollinators or mechanical fit. The match between nectary depth, which means the length of the tubular structure formed in many plant species to hide the nectary and store nectar, and the mouthparts length of its major nectar-foraging pollinators has been repeatedly demonstrated as an example, because this trait have shown a positive relationship with pollen removal and deposition in experimental manipulations in many synpetalous plants and orchid family. However, it remains unclear how pollinator-mediated selection affects the evolution of nectary depth in choripetalous and actinomorphic flowers, such as most flowers in Ranunculaceae. Here we investigated floral characteristics and pollinators in Urophysa rockii Ulbr. and U. henryi (Oliv.) Ulbr., as they are quite the same in habitat, anthesis and morphological characteristics except for nectary depth. Both of these species have flat white sepals and yellow petals each has a spatial structure at the base that contains nectar, but the nectary depth of U. rockii is deeper than that of U. henryi, for the former petals are shortly spurred about 3-4 mm in length while the latter are saccate. Meanwhile, the flowers of both species are most frequently visited by Apis cerana, the Chinese honey bee, and one or two species of hover fly, Syrphidae, but only A. cerana was able to forage nectar in U. rockii while all visitors can forage nectar in U. henryi. A. cerana always lands on the center of a flower and projects its proboscis into each petal when its thorax touches anthers and stigmas. The difference between two species is that U. rockii was visited by A. cerana with a higher frequency, longer visiting time per flower and more activities on flowers than U. henryi. Besides, the petal width and its nectary depth of U. rockii closely match the width of the labrum and the effective mouthparts length of A. cerana, respectively. Therefore, we concluded that pollinator-mediated selection played a vital role in the evolution of nectary depth in Urophysa, with deeper nectaries favoured through reproductive fitness, because this trait affects flower-pollinator interaction and therefore pollen deposition. We also detected deeper nectaries favoured because this trait also affects nectar accumulation as well as deeper nectaries can prevent inefficiency visitors from foraging nectar effectively.

Liparis wenshanensis, a new orchid species from China: Evidence from morphological and molecular analyses

A new orchid species, Liparis wenshanensis, discovered in Yunnan, China is described and illustrated in this study based on morphological and molecular analyses. A detailed comparison between the newly discovered orchid and other members of the genus, Liparis, was conducted. The new plant is characterized by the combination of the following features: a long rachis with 45 to 55 flowers; white sepals, petals and column; a greenish lip with a purplish center; strongly recurved and revolute dorsal sepals and petals; strongly recurved, oblong lateral sepals; a cordate lip that is strongly deflexed below the middle, with a two-lobed apex and a two-lobed callus at the base; an arcuate column with a lamella extending along the center almost to the stigma, and with a pair of broad wings toward the apex. These features distinguish the new orchid from all other known species of Liparis. We proceeded to a phylogenetic analysis to ascertain the systematic position of this enigmatic species. Molecular analyses based on nuclear ribosomal ITS and plastid matK DNA sequence data supports the recognition of L. wenshanensis as a distinct species.

Leaf Anatomy of Three Varians of Arundina graminifolia (D. Don.) Hochr

Three variations of Arundina graminifolia flowers have been recognized, (1) group of big flower with reddish violetlip and purplelish white sepals and petals (2) group of small flower with white lip and white sepals and petals (3)similar to second variation but with purple color on the lip apex. In order to clarify the taxonomy status of thosethree variations, a leaf anatomical study had been carried out. Results of this study showed that there were somedifferences among them in trichome shape and number mesophyll layers. Big flower group of Arundina hastrichome club shape and thick mucous in the apex with mesophyll layer 9-11; for small flower group has white lip,trichome club shape, thick mucous and granulate in the apex, but only 2 mesophyl layers; whereas for other smallflower group with purple lip has trichome cup shape and 10-13 layers of mesophyll. Based on the differences inflower size and their color variation, and combined with leaf anatomical study, we suggested the three variationsof A. graminifolia should be in separated groups.

Post-harvest browning syndrome and other qualities and defects in Backhousia myrtifolia

SummaryBackhousia myrtifolia is a species native to Australia that shows potential as a cut flower crop. During Spring and Summer, it bears numerous small florets with prominent white sepals and glossy deep-green foliage. B. myrtifolia is harvested either when tight white buds are present in the centre of the star-shaped sepals, or following bud burst, after the petals and stamens have abscised to leave only the sepals.Wilting and brown-to-black discolouration of the flowers and foliage can markedly reduce stem quality. Several forms of discolouration were characterised over the 2004 – 2006 flowering seasons and were collectively termed ‘post-harvest browning syndrome’. Further research based on the symptomatology described herein is required to elucidate the causal agent(s).

Overcoming the barrier to interspecific hybridization of Fagopyrum esculentum with Fagopyrum tataricum

Tartary buckwheat (Fagopyrum tataricum) was successfully hybridized with common buckwheat (F. esculentum), both diploid (2n=16), using the latter as male parent during bud pollination. The barrier normally encountered in such hybridization was overcome by enhancing the cross-compatibility of the two species, which was accomplished by synthesizing a unique genotype of common buckwheat. This novel plant was produced by selecting common buckwheat plants that exhibited, at isozyme loci PGM, SKDH and ADH, alleles with similar mobility to those found in tartary and then transferring these alleles to a single plant through six generations of breeding. Ovule culture was used to rescue the 7–10 day old embryos. On the rescue-culture medium 41% of the hybrid embryos formed calli larger than 200 μm in diameter. Most ceased to grow before reaching 1500 μm, but four out of 263 cultured ovules continued to grow as callus. One of these differentiated and formed callus with buds and shoots from which cloned plants were produced. The remaining embryos either did not grow at all or formed very small calli. When tartary was crossed with the original genotype of common buckwheat, only 22% of the hybrid embryos formed small calli and none differentiated. Hybridity of the calli and the plantlets was determined by RAPD and isozyme analysis, respectively. Flowers produced by the hybrid plants were of the same type (homomorphic) and size as those of tartary, but with white sepals like common buckwheat.

A recessive gene for white sepal colour in sweetclover, Melilotus alba L.

A genetic analysis involving P, F1, F2 and F3 in sweetclover (Melilotus alba L.) revealed that the white sepal trait was controlled by a single recessive gene, designated ws. This trait is characterized by chlorophyll-deficient white sepals and several associated pleiotropic effects including: lighter green colour of stems and foliage and a general greenish-red colour of the entire plant, lax and wilted appearance of the white sepal racemes, reduced opening of the mature flower, and a much reduced fertility as measured by percent pod set. Because of these regressive effects associated with the white sepal trait, it has limited use as a plant marker.Key words: Melilotus alba, white sepal, chimera, pleiotropy