Simple Inflorescences Research Articles

SUPERMAN genes: uncovering a new function in the development of complex inflorescences.

The Arabidopsis SUPERMAN (SUP) gene and its orthologs in eudicots are crucial in regulating the number of reproductive floral organs. In Medicago truncatula, in addition to this function, a novel role in controlling meristem activity during compound inflorescence development was assigned to the SUP-ortholog (MtSUP). These findings led us to investigate whether the role of SUP genes in inflorescence development was legume-specific or could be extended to other eudicots. To assess that, we used Solanum lycopersicum as a model system with a cymose complex inflorescence and Arabidopsis thaliana as the best-known example of simple inflorescence. We conducted a detailed comparative expression analysis of SlSUP and SUP from vegetative stages to flower transition. In addition, we performed an exhaustive phenotypic characterisation of two different slsup and sup mutants during the plant life cycle. Our findings reveal that SlSUP is required for precise regulation of the meristems that control shoot and inflorescence architecture in tomato. In contrast, in Arabidopsis, SUP performs no meristematic function, but we found a role of SUP in floral transition. Our findings suggest that the functional divergence of SUP-like genes contributed to the modification of inflorescence architecture during angiosperm evolution.

Epimedium daiguii (Berberidaceae), a new species from central China

Epimedium daiguii C. Zhang, B.L. Guo & Q.R. Liu, a new species of the Epimedium, is found and described from Wuling Mountains, Hunan Province, China. It should be a member of Epimedium sect. Diphyllon ser. Brachycerae due to the distinct minor flower feature. This new species resembles E. elachyphyllum (E. parvifolium) in flower traits. The stout rhizomes, flowering stem with two opposite trifoliolate leaves and paniculate inflorescences of this new species distinguish from E. elachyphyllum with elongated rhizomes, flowering stem with a single leaflet, and simple inflorescences.

Identification and characterization of putative targets of VEGETATIVE1/FULc, a key regulator of development of the compound inflorescence in pea and related legumes.

Inflorescence architecture contributes to essential plant traits. It determines plant shape, contributing to morphological diversity, and also determines the position and number of flowers and fruits produced by the plant, thus influencing seed yield. Most legumes have compound inflorescences, where flowers are produced in secondary inflorescences (I2), formed at the flanks of the main primary inflorescence (I1), in contrast to simple inflorescences of plants like Arabidopsis, in which flowers are directly formed on the I1. The pea VEGETATIVE1/FULc (VEG1) gene, and its homologs in other legumes, specify the formation of the I2 meristem, a function apparently restricted to legumes. To understand the control of I2 development, it is important to identify the genes working downstream of VEG1. In this study, we adopted a novel strategy to identify genes expressed in the I2 meristem, as potential regulatory targets of VEG1. To identify pea I2-meristem genes, we compared the transcriptomes of inflorescence apices from wild-type and mutants affected in I2 development, such as proliferating inflorescence meristems (pim, with more I2 meristems), and veg1 and vegetative2 (both without I2 meristems). Analysis of the differentially expressed genes using Arabidopsis genome databases combined with RT-qPCR expression analysis in pea allowed the selection of genes expressed in the pea inflorescence apex. In situ hybridization of four of these genes showed that all four genes are expressed in the I2 meristem, proving our approach to identify I2-meristem genes was successful. Finally, analysis by VIGS (virus-induced gene silencing) in pea identified one gene, PsDAO1, whose silencing leads to small plants, and another gene, PsHUP54, whose silencing leads to plants with very large stubs, meaning that this gene controls the activity of the I2 meristem. PsHUP54-VIGS plants are also large and, more importantly, produce large pods with almost double the seeds as the control. Our study shows a new useful strategy to isolate I2-meristem genes and identifies a novel gene, PsHUP54, which seems to be a promising tool to improve yield in pea and in other legumes.

A new species of Werauhia (Bromeliaceae, Tillandsioideae) from the highlands of southern Central America

The authors describe and illustrate a new species of Tillandsioid epiphytic bromeliad, Werauhia talamancana, from the mountains of southern Central America. This new species is related to W. brunei by its smooth, lustrous and distichous floral bracts (not secund) at anthesis but differs from the latter by its larger flowers and brown-maroon floral bracts (versus greenish). This new species belongs to section Werauhia and is part of a group of species with spicate simple inflorescences with relatively large floral bracts.

Three New and Endemic Species of Eriocaulaceae from Serra da Canastra, Minas Gerais, Brazil

Abstract—Three new species of Eriocaulaceae, endemic to the Serra da Canastra in Minas Gerais state, are described. Paepalanthus petraeus is assigned to P. ser. Paepalanthus, differing within the series by its thickened stem accumulating leaf sheaths, linear leaves, and numerous scapes shorter or equaling the leaf height and bearing capitula with brown involucral bracts. Paepalanthus sinuosus belongs to P. subsect. Polyactis and is distinguished by few scapes in lax fascicles, more than twice as long as the leaves, which are patent to slightly recurved, and light brown involucral bracts with acute apex. Syngonanthus culcitosus, within S. sect. Syngonanthus, is unique due to its elongate and branched stem forming dense mats, simple inflorescences, cream-colored involucral bracts equaling the length of the floral disc, and gynoecium with nectariferous appendages. Comparisons with the most similar species are provided for each new taxon. Maps, photographs, and illustrations are presented, together with comments on phenology, distribution, habitat, and morphology. Paepalanthus petraeus and P. sinuosus are likely to be assessed as Critically Endangered, and S. culcitosus as Vulnerable, according to IUCN criteria.

MtFULc controls inflorescence development by directly repressing MtTFL1 in Medicago truncatula

Flowering plants display a vast diversity of inflorescence architecture, which plays an important role in determining seed yield and fruit production. Unlike the model eudicot Arabidopsis thaliana that has simple inflorescences, most legume plants have compound types of inflorescences. Recent studies in the model legume species Pisum sativum and Medicago truncatula showed that the MADS-box transcription factors VEGETATIVE1/PsFRUITFULc/MtFRUITFULc (VEG1/PsFULc and MtFULc) are essential for the development of compound inflorescences by specifying the secondary inflorescence meristem identity. In this study, we report the isolation and characterization of two new mtfulc alleles by screening the M. truncatula Tnt1 insertion mutant collection. We found that MtFULc specifies M. truncatula secondary inflorescence meristem identity in a dose-dependent manner. Biochemical analysis and chromatin immunoprecipitation (ChIP) assays revealed that MtFULc acts as a transcriptional repressor to directly repress the expression of MtTFL1 through its promoter and 3′ intergenic region. Comprehensive genetic analysis suggest MtFULc coordinates with the primary inflorescence meristem maintainer MtTFL1 and floral meristem regulator MtPIM to control M. truncatula inflorescence development. Our findings help to elucidate the mechanism of MtFULc-mediated regulation of secondary inflorescence meristem identity and provide insights into understanding the genetic regulatory network underlying compound inflorescence development in legumes.

<p><strong><em>Tillandsia itatiensis</em></strong><strong>: a new species of <em>Tillandsia</em> L. (Bromeliaceae) from Bahia, Brazil</strong></p>

The authors describe, discuss, and illustrate Tillandsia itatiensis, a new species from the Caatinga biome in the municipality of Itatim, Bahia, Brazil. The new species is similar to T. streptocarpa and T. grao-mogolensis, regarding morphological characters such as caulescent habit, curved stem, simple inflorescence with no more than five flowers per inflorescence and simple-erect stigma. It inhabits inselbergs in Caatinga forest, where it is critically endangered (CR) due its small distribution and human extractivism.

<p><strong>A new <em>Werauhia </em>(Tillandsioideae, Bromeliaceae) from Mexico with observations about its reproductive biology</strong></p>

Werauhia maculata a new species from Tabasco, Mexico is described and illustrated. The new taxon possesses a large tank-rosette, with conspicuous and irregularly disposed dark purple marks on the basal portion of the leaves abaxial surface, a simple inflorescence, with secund and numerous whitish-flowers densely arranged on the rachis. The new taxon is compared with W. pectinata and W. noctiflorens, species with similar characteristics. In addition, some data about its reproductive biology are presented.

Study of flowering patterns of Campanula L. species using computer modeling

Long-term data on flowering phenology of 9 Campanula L. species were processed using computer modeling. Modified model is proposed to describe flowering of monocarpic shoots with multi-flowered inflorescences taking into account structural inflorescence features and morphogenesis of floral zone. The flowering patterns are determined by degree of inflorescence branching and sequence of flowers opening in them. It is shown that flowering curve for simple inflorescences is unimodal: it has single peak associated with opening of terminal flower and flowers on the 1st order axes. For compound inflorescences two maxima are noted (the second of them is due to opening of flowers on the 2nd order axes), or curve has wavy character. Regression curves describing sequence of flowers opening on the 1 st order axes are different. They are C-shaped if flowering begins in lower third of the inflorescence and then spreads divergently. More often terminal flower opens first, and is accompanied by several flowers in lower third of inflorescence, while next flowers open in divergent way. In this case the regression curves are S-shaped. The proposed model reproduces picture of individual flowering with natural variability, and can be used to describe flowering of various taxa of herbaceous plants with multi-flowered inflorescences.

<p><strong>A new species of <em>Phragmipedium</em> (Orchidaceae: Cypripedioideae) from Peru</strong></p>

A new species of Phragmipedium section Lorifolia, P. cabrejosii, is described and illustrated from Peru, and its affinities are discussed. It is mainly compared with P. caricinum, from which it is distinguished by the simple inflorescence, the elliptic dorsal sepal, that is apically white, the shorter, apically twisted pale yellow petals tinged with rose, and the ovate-subrhombic staminodial shield (vs. reniform).

Molecular evidence for repeated recruitment of wild Christmas poinsettia (Euphorbia pulcherrima) into traditional horticulture in Mexico

One of Mexico’s most emblematic and economically important plants is the poinsettia (Euphorbia pulcherrima). After nearly 200 years of poinsettia cultivation outside Mexico, more than 300 varieties of many different sizes, shapes and colors have been generated. However, studies on the management of or the evolutionary processes through which the changes present in cultivars have been generated, starting from wild plants, have not been carried out. In the present work, we tested the hypothesis that poinsettia plants living in human settlements represent transplanted wild plants. To test this hypothesis, we analyzed the genetic diversity and kin relationships of 58 poinsettia plants from 25 wild populations, 25 garden plants and 8 Mexican and foreign cultivars. Two non-coding intergenic chloroplast markers, trnG-trnS and psbA-trnH, were utilized to obtain the diversity indices and genealogies. The results support the transplanting of poinsettias hypothesis because garden plants share the same genetic variant as the wild populations and, in most cases, that of the closest wild populations. Some garden poinsettias have simple inflorescences, like the wild plants. The garden plants have a genetic diversity that is higher than in cultivars and that is shared with nearby wild populations. Additionally, some homeowners indicated that their plants were obtained from nearby hills. The transplanting of wild poinsettia plants to human settlements could have been one of the first steps in the domestication process of E. pulcherrima. Also, new genetic variants were found; one of these could be Euphorbia fastuosa, an invalid name for E. pulcherrima proposed by Sesse and Mocino between 1787 and 1803.

A sticky and heavily armed new species of Solanum (Solanumsubg.Leptostemonum, Solanaceae) from eastern Brazil.

We describe a new species of spiny Solanum (Solanumsubg.Leptostemonum), endemic to the Brazilian Atlantic Forest and associated with granitic outcrops (inselbergs or sugar loaf mountains). Solanumkollastrum Gouvêa & Giacomin, sp. nov. is morphologically similar to the poorly known S.sublentum Hiern, but is a heavily armed, much more robust plant with stellate-glandular indumentum. Together with S.sublentum, it is morphologically related to some species of Solanum such as S.hexandrum Vell., S.robustum H.Wendl., and S.stagnale Moric. that share strongly accrescent calyces, large leaves with the bases decurrent on to the petiole, pendent simple inflorescences and large, robust flowers. The new species is restricted to a few known populations in southern Bahia and north-eastern Minas Gerais states and conservation efforts are needed.

Resource reallocation patterns within Sagittaria trifolia inflorescences following differential pollination

Understanding resource allocation to reproduction, a key factor in life history tradeoffs, has long intrigued plant ecologists. Despite the recognized importance of understanding the movement of resources among flowers following variable pollination, the patterns of resource reallocation to plant reproductive organs have not been thoroughly addressed. In this study, we aimed to empirically explore how resources redistribute within inflorescences in response to differential pollination intensities. Using a common herb, Sagittaria trifolia, we conducted supplemental and controlled pollination for single, some, or all flowers in simple and complex inflorescences, and compared their resulting fruiting probabilities, seed production, and average seed masses. Pollen supplementation of a single flower significantly increased its fruiting probability; however, the same manipulation of an inflorescence did not increase its overall reproduction. Single pollen-supplemented flowers had a higher percentage fruit set than inflorescences receiving supplemental pollination. In complex inflorescences, supplemental pollination had no effect on the reproductive success of flowers on the lateral or main branches. We provided evidence of resource reallocation from controlled to pollen-supplemented flowers in simple inflorescences; however, resources were unlikely to be reallocated between the main and lateral branches in the complex inflorescences, suggesting that flowering branches represent integrated physiological units in S. trifolia. The results also demonstrated that single-flower supplemental pollination would exaggerate pollen limitation and lead to a biased understanding of a plant's reproductive status.

Pitcairnia singularis (Pitcairnioideae, Bromeliaceae), a new species from Jalisco, Mexico

Pitcairnia singularis, known only from the municipality of Puerto Vallarta in the state of Jalisco, Mexico, is here described and illustrated. The new species is characterized by very narrow, epetiolate, deciduous normal leaves, a simple inflorescence with 14–20 pedicellate, secund, white flowers, and petals 1.5–1.7 cm long, without appendages. An identification key has been included for all the species of the genus present in the state of Jalisco, Mexico.

Nomenclatural notes on Goeppertia (Marantaceae)

A recent molecular based phylogeny (Borchsenius et al. 2012) redefined the genus Goeppertia Nees (1831: 337) to include all the subgenera of Calathea Meyer (1818: 6) proposed by Schumann (1902) with the exception of C. subgenus Calathea Körnicke (1862: 112). As a result, several species of Calathea recently described were transferred to Goeppertia (Braga 2014). Similarly, a taxonomic revision of the Brazilian species, currently carried out by the first author, led to the conclusion that Calathea polytricha Baker (1894: 497) should be combined in Goeppertia. This species features the synapomorphies of Goeppertia, such as simple inflorescences and corolla lobes straight to spreading, and belongs to Schumann’s subgenus Pseudophrynium Körnicke (1862: 113). During the taxonomic revision, other names have been considered synonyms and are typified here.

Genetic control of inflorescence architecture in legumes.

The architecture of the inflorescence, the shoot system that bears the flowers, is a main component of the huge diversity of forms found in flowering plants. Inflorescence architecture has also a strong impact on the production of fruits and seeds, and on crop management, two highly relevant agronomical traits. Elucidating the genetic networks that control inflorescence development, and how they vary between different species, is essential to understanding the evolution of plant form and to being able to breed key architectural traits in crop species. Inflorescence architecture depends on the identity and activity of the meristems in the inflorescence apex, which determines when flowers are formed, how many are produced and their relative position in the inflorescence axis. Arabidopsis thaliana, where the genetic control of inflorescence development is best known, has a simple inflorescence, where the primary inflorescence meristem directly produces the flowers, which are thus borne in the main inflorescence axis. In contrast, legumes represent a more complex inflorescence type, the compound inflorescence, where flowers are not directly borne in the main inflorescence axis but, instead, they are formed by secondary or higher order inflorescence meristems. Studies in model legumes such as pea (Pisum sativum) or Medicago truncatula have led to a rather good knowledge of the genetic control of the development of the legume compound inflorescence. In addition, the increasing availability of genetic and genomic tools for legumes is allowing to rapidly extending this knowledge to other grain legume crops. This review aims to describe the current knowledge of the genetic network controlling inflorescence development in legumes. It also discusses how the combination of this knowledge with the use of emerging genomic tools and resources may allow rapid advances in the breeding of grain legume crops.

Regulation of inflorescence architecture by cytokinins.

In flowering plants, the arrangement of flowers on a stem becomes an inflorescence, and a huge variety of inflorescence architecture occurs in nature. Inflorescence architecture also affects crop yield. In simple inflorescences, flowers form on a main stem; by contrast, in compound inflorescences, flowers form on branched stems and the branching pattern defines the architecture of the inflorescence. In this review, we highlight recent findings on the regulation of inflorescence architecture by cytokinin plant hormones. Results in rice (Oryza sativa) and Arabidopsis thaliana show that although these two species have distinct inflorescence architectures, cytokinins have a common effect on inflorescence branching. Based on these studies, we discuss how cytokinins regulate distinct types of inflorescence architecture through their effect on meristem activities.

Taxonomic Notes on <I>Vriesea</I> Sect. <I>Xiphion</I> (Bromeliaceae) with Descriptions of Three New Species

Abstract Vriesea is a large genus comprising several groups of species with controversial limits. The taxonomic revision of small monophyletic groups has been an important approach to improve our understanding of the taxonomy of the genus. After the taxonomic revision of the monophyletic group belonging to Vriesea sect. Xiphion, comprised of species with simple inflorescences, flowers patent during anthesis and not secund, and decurrent floral bract bases, this paper describes three species as new: Vriesea carmenae, Vriesea gelatinosa, and Vriesea zildae; and proposes one synonym. The species occur mainly in the Brazilian Atlantic Forest and Cerrado domains, and are morphologically similar to V. bituminosa and V. wawranea.

Taxonomy and lectotypification of Vriesea fenestralis Linden et André (Bromeliaceae)1

A taxonomic review of the species of Vriesea sect. Xiphion with simple inflorescences indicated that a lectotype for Vriesea fenestralis Linden & André was needed because its holotype cannot be found. We have designated the lectotype and provide a list of studied material along with comments on the geographic distribution, taxonomy and conservation of the species.

Review of ChineseSpiraea(Rosaceae, Spiraeoideae) with Simple Inflorescences

Several morphotypes of simple inflorescences occurring in the genus Spiraea L. (Rosaceae), widely used for classification and determination, but not uniformly interpreted in the literature, are correctly defined. Taxonomically, S. compsophylla Hand.-Mazz. is synonymized with the imperfectly known S. calcicola W. W. Sm., whose amplified description and illustration are added. A newly distinguished species, hitherto confused with the former name, is described from Yunnan Province in China and illustrated as S. adiantoides Businský, with its assignment to section Glomeratae Nakai. Two imperfectly known and confused species of Spiraea sect. Chamaedryon Ser. from Taiwan, S. tarokoensis Hayata and S. tatakaensis I. S. Chen, are carefully described, illustrated, and compared with six similar Chinese species. A new variety, S. lasiocarpa var. villosa Businský, is described from western Sichuan Province, accepting the concept that S. lasiocarpa Kar. & Kir., described from today's eastern Kazakhstan and hitherto neglected in Chinese floras, is the correct name for the Chinese taxon S. mongolica Maxim. Two imperfectly known taxa from southwestern Sichuan, S. muliensis T. T. Yu & L. T. Lu and S. daochengensis L. T. Lu, were found to be conspecific after comparison of their respective holotypes and a newly found population; the former is accepted as the correct name. Spiraea sericea Turcz. is accepted only at the rank of the variety as S. media Schmidt var. sericea (Turcz.) Maxim. A key to the Chinese species of Spiraea with simple inflorescences is newly compiled, encompassing 40 species.