Inflorescence Morphology Research Articles

Identification of Wheat Inflorescence Development-Related Genes Using a Comparative Transcriptomics Approach

Inflorescence represents the highly specialized plant tissue producing the grains. Although key genes regulating flower initiation and development are conserved, the mechanism regulating fertility is still not well explained. To identify genes and gene network underlying inflorescence morphology and fertility of bread wheat, expressed sequence tags (ESTs) from different tissues were analyzed using a comparative transcriptomics approach. Based on statistical comparison of EST frequencies of individual genes in EST pools representing different tissues and verification with RT-PCR and RNA-seq data, 170 genes of 59 gene sets predominantly expressed in the inflorescence were obtained. Nearly one-third of the gene sets displayed differentiated expression profiles in terms of their subgenome orthologs. The identified genes, most of which were predominantly expressed in anthers, encode proteins involved in wheat floral identity determination, anther and pollen development, pollen-pistil interaction, and others. Particularly, 25 annotated gene sets are associated with pollen wall formation, of which 18 encode enzymes or proteins participating in lipid metabolic pathway, including fatty acid ω-hydroxylation, alkane and fatty alcohol biosynthesis, and glycerophospholipid metabolism. We showed that the comparative transcriptomics approach was effective in identifying genes for reproductive development and found that lipid metabolism was particularly active in wheat anthers.

Diversity, systematics, and evolution of Cynodonteae inflorescences (Chloridoideae – Poaceae)

The species of the Cynodonteae tribe show great morphological diversity in their reproductive structures. Previous studies where inflorescences were comparatively analysed in the context of phylogeny have shown that although grass inflorescences seem to be excessively variable, there are certain aspects of inflorescences that store relevant information on the evolution and systematics in Poaceae. We have analysed and compared the inflorescence structures of species belonging to the Hilariinae, Monanthochloinae, Scleropogoninae, and Muhlenbergiinae subtribes. Considering the most relevant morphological characters, the most recurrent types of inflorescences in the lineage were determined by means of a principal coordinates analysis. To understand the evolution of inflorescence morphology, ancestral reconstructions of inflorescence characters were performed using the Bayesian inference method. The results obtained demonstrate that the processes of homogenization and truncation might account for the diversity observed in adult inflorescences. Five different types of inflorescences were identified out of 36 theoretical possibilities. Amongst these, inflorescence type 1 (panicle of spikelets, with a terminal spikelet, non-homogenized, and bearing third- or higher-order branches) was found to be the most frequent in the studied group. Ancestral reconstructions of morphological characters allowed us to suggest that the ancestor of the group might have had an inflorescence with the form of a raceme of spikelets, non-truncated and bearing first-order branches. More complex inflorescences bearing no terminal spikelets and having branches of higher order might have diverged this lineage.

Genome-Wide Association Study Reveals Candidate Genes for Control of Plant Height, Branch Initiation Height and Branch Number in Rapeseed (Brassica napus L.).

Plant architecture is crucial for rapeseed yield and is determined by plant height (PH), branch initiation height (BIH), branch number (BN) and leaf and inflorescence morphology. In this study, we measured three major factors (PH, BIH, and BN) in a panel of 333 rapeseed accessions across 4 years. A genome-wide association study (GWAS) was performed via Q + K model and the panel was genotyped using the 60 k Brassica Infinium SNP array. We identified seven loci for PH, four for BIH, and five for BN. Subsequently, by determining linkage disequilibrium (LD) decay associated with 38 significant SNPs, we gained 31, 15, and 17 candidate genes for these traits, respectively. We also showed that PH is significantly correlated with BIH, while no other correlation was revealed. Notably, a GA signaling gene (BnRGA) and a flowering gene (BnFT) located on chromosome A02 were identified as the most likely candidate genes associated with PH regulation. Furthermore, a meristem initiation gene (BnLOF2) and a NAC domain transcriptional factor (BnCUC3) that may be associated with BN were identified on the chromosome A07. This study reveals novel insight into the genetic control of plant architecture and may facilitate marker-based breeding for rapeseed.

Inflorescence morphology and development in the basal rosid lineage Vitales

AbstractThis review summarizes inflorescence developmental morphology in the grape order Vitales within a phylogenetic context. Inflorescences in the shrubby Leeaceae are terminal thyrses that appear leaf‐opposed once renewal growth begins. Plants of the Vitaceae are mainly tendrilled lianas and form five well‐defined clades. Inflorescences develop from the unique, non‐leafy, uncommitted primordium which arises opposite a leaf on the flank of the shoot apical meristem, and may mature into an inflorescence, tendril, or a combination of the two. The Ampelopsis‐Rhoicissus clade, Cissus antarctica group and Yua have a tendril/inflorescence, with cymose branching on the inflorescence axis. Inflorescences in the core Cissus clade and Cyphostemma‐Tetrastigma clade arise on a compressed axillary shoot, and leaf‐opposed tendrils arise on the main shoot, resulting in different branch orders. In Parthenocissus, tendrils are leaf‐opposed on long shoots, and inflorescences are leaf‐opposed on axillary branches on short shoots. In the Ampelocissus‐Vitis clade, the leaf‐opposed tendrils and thyrse inflorescences are of the same branching order, and are often combined. Terminal inflorescences such as in Leeaceae are common in angiosperms, in contrast to the unique leaf‐opposed tendril/inflorescence of Vitaceae. The further separation of the tendrils and inflorescences onto different orders of branching (core Cissus, Cyphostemma‐Tetrastigma), or separate short and long shoots (Parthenocissus), have allowed each component to optimize its own function. The Ampelocissus‐Vitis clade, however, has returned to a thyrse inflorescence, which may allow for larger or unusual lamellate inflorescences (Pterisanthes), and has reunited tendrils and inflorescences. Thus, each clade has developed its own set of inflorescence morphology.

Two peculiar new species of Heteranthera Ruiz & Pavón (Pontederiaceae) from Brazil, with notes on inflorescence architecture in the family.

Two new and peculiar species of Heteranthera are herein described. Heteranthera catharinensis is unique in the genus due to its glomerulate, many-flowered inflorescences, in which the flowers are restricted to the base and apex of the cincinni. It also possesses the biggest flowers in the H. reniformis Ruiz & Pavón species complex, with glabrous perianth lobes, medial filament, and style. On the other hand, Heteranthera pumila is described as the smallest known species of Pontederiaceae, with its dwarf stature, petiolate leaves with especially diminute blades, inflorescences 1–2–(3)-flowered, peduncle densely covered with glandular hairs, basal bract with glandular hairs at base, and smooth seeds, rarely possessing 7–9 inconspicuous longitudinal wings. We present detailed descriptions, illustrations, comments, a distribution map, conservation assessments for the new species, and an identification key to the Brazilian species of Heteranthera s.l. Finally, we discuss inflorescence morphology and terminology in Pontederiaceae, characterizing it as thyrsoid.

A new species of Dieffenbachia (Araceae) from Limón Province, Costa Rica

Abstract Dieffenbachia rodriguezii, is described as a species new to science. It is known only from Limon Province at 1400 m, in a Lower montane rain forest life zone. Based on inflorescence morphology and leaf-blade shape, the new species is most similar to Dieffenbachia oerstedii Schott, Dieffenbachia grayumiana Croat and Dieffenbachia killipii Croat. The affinities of this species are discussed and a key for Costa Rican Dieffenbachia is provided.

Seed Production Estimation for Mountain Big Sagebrush (Artemisia tridentata ssp. vaseyana)

Seed production is an essential component of postdisturbance recovery for mountain big sagebrush (Artemisia tridentata Nutt. ssp vaseyana [Rydb] Beetle; MBS). We tested a method for rapid estimation of MBS seed production using measurements of inflorescence morphology. We measured total stem length, stem length from first branchlet to stem tip, stem diameter, fresh weight, and number of stem branchlets for 750 inflorescences collected from five central and southern Utah sites. Florets per inflorescence were counted to provide an estimate of seed production potential. We used regression analysis to assess associations between morphological traits and potential seed production and evaluated the efficiency and scalability of each measure for field application. Site means for morphological measures varied ~2 to 11-fold while mean number of florets per inflorescence varied ~ 8-fold. Inflorescence weight was the best predictor of seed production potential (P < 0.0001, r2 = 0.897), although correlations for all tested variables were highly significant. Among-site differences in regression equations for this relationship were not significant (P = 0.226), suggesting that a single conversion factor may have broad application. However, validation will require additional testing across a broader range of sites and field conditions. Scalable methods for efficient estimation of sagebrush seed production potential, such as those evaluated in this study, could be useful for managers charged with assessing variability in sagebrush community stability.

Lasiosiphon esterhuyseniae (Thymelaeaceae: Thymelaeoideae), a new species from Northern Cape (South Africa), and the transfer of two additional southern African species to the genus

We describe a new species, Lasiosiphon esterhuyseniae Magee & J. C. Manning, for a rigid, densely branched shrublet from the Kalahari Region, Northern Cape, South Africa. Due to the relatively restricted range, the lack of recent records (the most recent from 1940) and the lack of information regarding its palatability we recommend an IUCN status of Data Deficient. Two additional southern African taxa with the inflorescence and floral morphology diagnostic for Lasiosiphon, but currently still included in Gnidia, were encountered and new combinations for these species are provided, viz. Lasiosiphon microcephalus (Meisn.) J. C. Manning & Magee and L. rubescens (B. Peterson) J. C. Manning & Magee. As a result 29 species of Lasiosiphon are now recognised in southern Africa and a complete listing of these species is provided.

Pre-budburst temperature influences the inner and outer arm morphology, phenology, flower number, fruitset, TSS accumulation and variability ofVitis viniferaL. Sauvignon Blanc bunches

Background and Aims: Inflorescence morphology, flower formation and subsequent fruit development of grapevines are influenced by genetic, environmental and cultural practices. While the effect of temperature on inflorescence primordia number per bud is documented, its effect during dormancy and budburst (BB) on floral development is less clear. In our study, winter dormant buds were passively heated for different periods of time from mid-winter (July) to BB (October). Methods and Results: Individual canes were heated pre-BB for different periods in polyethylene tunnels. Heating during winter dormancy had no effect on the number or position of inflorescences on the shoot, or on the type of structure occurring at the outer arm position of the inflorescence. Heating buds for either July or August to BB advanced the date of BB and the start date of flowering by 12–14 and 14 days, respectively, compared with that of the unheated Control treatment. There was a significant (P < 0.05) negative correlation between the mean temperature 12 days pre-BB and flower number per shoot. The time between 50% flowering and the fruit TSS reaching 14°Brix was not influenced by winter heating or the date of flowering; the difference in this time interval, however, between the inner and outer arm components increased as shoot node number increased. Conclusions: Flower number per inflorescence had the greatest influence on the proportion of fruitset. The date of flowering of the outer arm was later at higher inflorescence positions on the shoot and later than that of the inner arm. Likewise, the outer arms of bunches higher up the shoot took longer from flowering to accumulate a fruit TSS of 14°Brix. Significance of the Study: Much of the within-vine variability in berry composition at harvest can be attributed to the position of bunches on the shoot and the presence of an outer arm. The outer arm on apical bunches took significantly longer to progress from flowering to a fruit TSS of 14°Brix, suggesting that removal would significantly reduce within-vine fruit variability.

Study on early inflorescence development in bread wheat (T. aestivum L.) lines with non-standard SCR-morphotype

Features of wheat (Triticum aestivum L.) inflorescence development define its architecture and have an impact on yield potential. Wheat lines and forms with altered inflorescence morphology are important genetic resources for the study on the genetic mechanisms underlying plant developmental programs and inflorescence architecture; they are also important for practical use to increase productivity. Normally, wheat spikelets are arranged in two parallel rows along the spike axis. The SCR (screwed spike rachis) lines represent a non-standard morphotype, which is characterized by a spiral arrangement of spikelets along the spiked rachis. The study of the early stages of the inflorescence development in SCR-lines using light and scanning electron microscopy revealed that the spiral arrangement of spikelets were not related to changes at the early stage of inflorescence development, and resulted from spiral growth of spike rachis cells at later stages of spike growth. Thus, the spiral arrangement of spikelets in cereal inflorescence may have resulted not only from peculiarities of the mutual arrangement of spikelet meristems (phyllotaxis), but also from cell growth features at later stages of inflorescence growth. It was shown that SCR is inherited as a dominant monogenic trait; its expression can be modified by genotypic background. The SCR-lines characterized using light and scanning electron microscopy represent an important genetic resource for further study of the molecular-genetic mechanisms determining plant architecture. Furthermore, they can be used to develop wheat lines and cultivars with new inflorescence phenotypes.

Alterations of CorTFL1 and CorAP1 expression correlate with major evolutionary shifts of inflorescence architecture in Cornus (Cornaceae) - a proposed model for variation of closed inflorescence forms.

TFL1-, AP1- and LFY-like genes are known to be key regulators of inflorescence development. However, it remains to be tested whether the evolutionary modifications of inflorescence morphology result from shifts in their expression patterns. We compared the spatiotemporal expression patterns of CorTFL1, CorAP1 and CorLFY in six closely related Cornus species that display four types of closed inflorescence morphology using quantitative real-time polymerase chain reaction (qRT-PCR) and RNA insitu hybridization. Character mapping on the phylogeny was conducted to identify evolutionary changes and to assess the correlation between changes in gene expression and inflorescence morphology. Results demonstrated variation of gene expression patterns among species and a strong correlation between CorTFL1 expression and the branch index of the inflorescence type. Evolutionary changes in CorTFL1 and CorAP1 expression co-occurred on the phylogeny with the morphological changes underpinning inflorescence divergence. The study found a clear correlation between the expression patterns of CorTFL1 and CorAP1 and the inflorescence architecture in a natural system displaying closed inflorescences. The results suggest a role for the alteration in CorTFL1 and CorAP1 expression during the evolutionary modification of inflorescences in Cornus. We propose that a TFL1-like and AP1-like gene-based model may explain variation of closed inflorescences in Cornus and other lineages.

CYCLOIDEA 2 Clade Genes: Key Players in the Control of Floral Symmetry, Inflorescence Architecture, and Reproductive Organ Development

Undoubted lines of evidence point out that members of CYCLOIDEA (CYC) 2 clade are essential players to control flower symmetry and, amusingly, also are determinants of capitula architecture (pseudanthium). In several species, CYC-like genes influence the androecium patterning, but to date, the function of these genes in the development of gynoecium organs is less clear. In this review, we first reported details about floral symmetry and an overview of genes and molecular mechanisms regulating the development of zygomorphism in different angiosperm lineages (e.g., basal and core eudicots and monocots). Then, we paid emphasis on the role of CYC-like genes in the development of heterogamous inflorescence of sunflower as well as other Asteraceae and some species within the Dipsacaceae family. Helianthus annuus is particularly attractive because it represents a useful model to study the role of CYC-like genes on shaping floral corolla as well as the differentiation of reproductive organs in different flowers of pseudanthia. A special attention was reserved to inflorescence morphology mutants of sunflower (i.e., Chrysanthemoids2 and tubular ray flower) because they provide useful information on the role of CYC-like genes in the radiate capitulum evolution. Finally, we discuss data from literature to suggest that CYC-like genes are also co-opted to regulate stamen and carpel differentiation likely throughout their interaction with the cell cycle and flower organ identity genes. The recruitment of reproductive organs in ray flowers also supports the phylogenetic origin of a radiate inflorescence of sunflower from a discoid capitulum and suggests that in sterile zygomorphic ray flower primordia the latent identity to differentiate both microsporangium and macrosporangium was conserved.

Evaluation of Morphological Diversity of Conserved Tall Coconut (&lt;em&gt;Cocos nucifera&lt;/em&gt; L.) germplasm in Sri Lanka

Coconut is the most widespread plantation crop in Sri Lanka. Characterisation of conserved coconut germplasm has been undertaken globally for identification of important features of different accessions for them to be effectively used in coconut breeding. The current study aimed at characterizing conserved coconut germplasm in Sri Lanka for quantitative traits with morphological descriptors pertaining to stem, leaf and inflorescence characters. Twelve coconut accessions belonging to variety Typica (Tall) conserved ex-situ gene bank in Pallama, Coconut Research Institute of Sri Lanka were used for recording morphological data. A total of 19 descriptors listed by Bioversity International for stem, leaf and Inflorescence morphology were recorded. Results analysis was performed in SAS v8 and Minitab v14. Analysis of variance revealed significant differences for 13 traits and Principal Component Analysis revealed the traits which contributed in higher magnitudes for the observed variation. Results revealed morphologically diverse accessions among the studied germplasm and provided evidence for the morphological variation among the different accessions having different origins although all the accessions were primarily of the same coconut variety. This indicates the effectiveness of sampling in the conservation process. Furthermore, the information derived in the present study will be useful in coconut breeding for desirable traits and also in formulating further conservation strategies.

Variability of the inflorescence morphology of Carex spicata (Cyperaceae) and its implication to taxonomy

Plants growing in different kinds of habitats are expected to show high morphological plasticity. Carex spicata Huds. occurs in different plant communities and shows distinct morphological variability of the inflorescences. Field observations carried out in different plant communities permitted us to hypothesize that the morphological variability of C. spicata inflorescences may to some degree be the result of the habitat. The objective of this study was to test that hypothesis for C. spicata by collecting inflorescences and measuring their morphological features from several populations in each of six plant communities: Agropyro‐Urticetum dioiceae, Arrhenatheretum elatioris, Lolio‐Cynosuretum, Lolio‐Plantaginetum, Trifolio‐Agrimonietum, and Stellario‐Deschampsietum. The following inflorescence features were analyzed: length of the lowest spikelet, distance between two lowest spikelets, length of inflorescence, number of spikelets, and length proportion of the lowest spikelet to the distance between the two lowest spikelets. We found that all analyzed morphological characters differed significantly among the plant communities. Furthermore, we found significant differences among populations within the six plant communities. Moreover, C. spicata inflorescences often have morphological features (i.e. a less crowded inflorescence with a relatively large distance between the two lowest spikelets) similar to the closely related species C. muricata L. Thus, the limited diagnostic value of inflorescence crowding, especially in vegetative or early fruiting phases, suggests that the taxonomic importance of this character should be reconsidered.

Morphology and Anatomy ofGuacamaya superba(Rapateaceae) and Schoenocephalieae with Notes on the Natural History of theFlor de inírida

Abstract. Rapateaceae are a monophyletic family of 17 genera with greatest species diversity on the mountains and savannas of the Guiana Shield. The family has intrigued botanists because of their interesting and unusual inflorescence and leaf morphologies. The small tribe Schoenocephalieae (three genera and seven species) are regionally prized for their showy inflorescences that are harvested as everlasting flowers. Here, we report on local cultivation efforts to minimize harvesting from wild populations and examine vegetative morphology and anatomy, reporting for the first time the presence of a lateral thickening meristem in Rapateaceae. Schoenocephalieae exhibit possible adaptations to their oligotrophic, open, and fire-prone habitats such as abundant mucilage, idioblasts containing a tannin-like substance, leaf fibers, presence of epidermal silica, the formation of telmata in Guacamaya, and vesicular-arbuscular mycorrhizal fungi.

Synopsis of Bunchosia Kunth (Malpighiaceae) from the Atlantic Forest

As part of the ongoing revision of Malpighiaceae from the Atlantic Forest, an extensive review of Vellozo’s Flora fluminensis and the names associated to the Bunchosia maritima complex was carried out. We conclude that seven species should be recognized, with four of them related to the morphological complex. Each of the seven species can be distinguished by the number of glands on the abaxial side of the leaf blade, venation pattern, inflorescence, androecium and drupe morphology, and number of carpels. Thus, we redefine B. maritima to a much narrower sense. In order to determine proper nomenclature for the recognized species, the typification of all names was investigated. We designate a lectotype and an epitype for B. maritima, a lectotype for B. apiculata and a neotype for B. fluminensis. Furthermore, we present an identification key for the Bunchosia species from the Atlantic Forest domain.

Inflorescence and floral characters indicating C&lt;sub&gt;3&lt;/sub&gt; and C&lt;sub&gt;4&lt;/sub&gt; photosynthesis in some species of the genus &lt;i&gt;Cyperus&lt;/i&gt; L. (Cyperaceae)

Inflorescence and floral morphological characters in twelve species of Cyperus – a genus known to have C 3 and C 4 photosynthetic species – were investigated in order to check their usefulness in delimiting species into photosynthetic groups. Plant species were collected from different locations within Southwestern Nigeria. Qualitative characters were noted and recorded while some quantitative characters were measured with metric ruler to the nearest centimeter and others were counted. The results revealed that compound umbellate inflorescence, digitately arranged spikelets and short spikelets not over 1cm long are characters that separate C. difformis and C. haspan which are C 3 species, while the rest with simple umbellate inflorescence, spicate spikelets and spikelet length over 1cm are C 4 species. Cyperus dilatatus , a species without a previous record of photosynthetic grouping, is hereby grouped as a C 4 species since it shared characters with the rest C 4 species. From this study, a combination of characters was identified, which can possibly be used along with known data from other sources in the grouping of Cyperus species as either C 3 or C 4 species. Data on C. dilatatus also showed that it possibly belong to C 4 species. This is probably the first known report on photosynthetic grouping of this species. © 2015 International Formulae Group. All rights reserved. Keywords: C 3 - C 4 species, Cyperus genus, inflorescence morphology, photosynthetic grouping, taxonomy

Floral traits and pollination ecology of European Arum hybrids.

Hybridisation is common in plants and can affect the genetic diversity and ecology of sympatric parental populations. Hybrids may resemble the parental species in their ecology, leading to competition and/or gene introgression; alternatively, they may diverge from the parental phenotypes, possibly leading to the colonisation of new ecological niches and to speciation. Here, we describe inflorescence morphology, ploidy levels, pollinator attractive scents, and pollinator guilds of natural hybrids of Arum italicum and A. maculatum (Araceae) from a site with sympatric parental populations in southern France to determine how these traits affect the hybrid pollination ecology. Hybrids were characterised by inflorescences with a size and a number of flowers more similar to A. italicum than to A. maculatum. In most cases, hybrid stamens were purple, as in A. maculatum, and spadix appendices yellow, as in A. italicum. Hybrid floral scent was closer to that of A. italicum, but shared some compounds with A. maculatum and comprised unique compounds. Also, the pollinator guild of the hybrids was similar to that of A. italicum. Nevertheless, the hybrids attracted a high proportion of individuals of the main pollinator of A. maculatum. We discuss the effects of hybridisation in sympatric parental zones in which hybrids exhibit low levels of reproductive success, the establishment of reproductive barriers between parental species, the role of the composition of floral attractive scents in the differential attraction of pollinators and in the competition between hybrids and their parental species, and the potential of hybridisation to give rise to new independent lineages.

Phytoliths in Chinese foxtail millet (Setaria italica)

Increasingly, archeologists are realizing that early agriculturalists manipulated suites of plant species as they contended with environmental instability and cultural performance. Studying these complex interactions requires robust diagnostic indicators for each species. This has been particularly difficult for millet macrobotanical remains in Asia. Microbotanical remains, such as phytoliths, offer a possible alternative for millet identification. To date, work on Setaria phytoliths has focused on a restricted number of species, limiting the confidence of identifying domesticated Setaria. Here we present the results of morphometric analysis of both leaf and inflorescence morphology across 12 of the 14 species of Setaria found in China today. Results suggest that robust discrimination of Setaria italica requires measurements of two types of inflorescence bract cells.

Harvest times of Comanthera elegans, a worldwide traded Brazilian species of everlasting flower: implications on seed production, germination, and on species management

Comanthera elegans (Bong.) L.R. Parra & Giul (“sempre-viva-pe-de-ouro”) is one of the most economically important species among the Eriocaulaceae in Brazil. Its inflorescences are used to make handicrafts and have long been exported to all over the world. The collection period usually begins in the second half of April and extends to May, occasionally until the first half of June. We assessed seed production and germinability throughout the 2006 harvest season: April–November, as well as the variation in morphology and anatomy of inflorescences along this period. In the evaluated flowering, seeds still had not yet been completely formed by early April, the onset month of commercial collection. Instead, germinable seeds were first observed in May, while seed dispersal was already in progress in early June. Collection in June resulted in plant uprooting, due to the tighter attachment of the scape to the rosette. The beginning and peak of germination occurred earlier for seeds from the most delayed collections, and the highest germinability was presented by seeds collected in September. We showed that the best period for the plant sexual reproduction surpasses the best period for commercial collection. Due to the onset of germinable seeds only as late as at the second half of the harvesting period, encouraging the delayed beginning of inflorescence collection may well represent a management strategy. Furthermore, the reservation of non-harvesting areas, which would secure the maintenance of plant populations in the wild and thus guarantee seed production and dispersal; maintaining remnants of inflorescences in collected areas; and encouraging cultivation should be considered.