Chapter Ten - Molecular Control of Inflorescence Development in Asteraceae

Plant-specific TCP domain transcription factors have been shown to regulate morphological novelties during plant evolution, including the complex architecture of the Asteraceae inflorescence that involves different types of flowers. We conducted comparative analysis of the CYCLOIDEA/TEOSINTE BRANCHED1 (CYC/TB1) gene family in Gerbera hybrida (gerbera) and Helianthus annuus (sunflower), two species that represent distant tribes within Asteraceae. Our data confirm that the CYC/TB1 gene family has expanded in Asteraceae, a condition that appears to be connected with the increased developmental complexity and evolutionary success of this large plant family. Phylogenetic analysis of the CYC/TB1 gene family revealed both shared and lineage-specific duplications in gerbera and sunflower, corresponding to the three gene lineages previously identified as specific to core eudicots: CYC1, CYC2, and CYC3. Expression analyses of early stages of flower primordia development indicated that especially within the CYC2 clade, with the greatest number of secondary gene duplications, gene expression patterns are conserved between the species and associated with flower and inflorescence development. All sunflower and gerbera CYC2 clade genes showed differential expression between developing flower types, being upregulated in marginal ray (and trans) flowers. One gene in gerbera (GhCYC3) and two in sunflower (HaCYC2d and HaCYC2c) were indicated to be strong candidates as regulators of ray flower identity, a function that is specific for Asteraceae. Our data further showed that other CYC2 clade genes are likely to have more specialized functions at the level of single flowers, including the late functions in floral reproductive organs that may be more conserved across plant families. The expression patterns of CYC1 and CYC3 clade genes showed more differences between the two species but still pointed to possible conserved functions during vegetative plant development. Pairwise protein-protein interaction assays gave the first molecular evidence that CYC/TB1-like proteins function in complexes. Compared with sunflower, the gerbera proteins showed higher capacity for dimerization, between as well as within CYC clades. Our data from two distant species within the Asteraceae suggest that the expansion and the apparent conservation of especially the CYC2 clade CYC/TB1-like genes are associated with the evolution of the increased complexity of the Asteraceae inflorescence architecture.

Development of composite inflorescences in the plant family Asteraceae has features that cannot be studied in the traditional model plants for flower development. In Gerbera hybrida, inflorescences are composed of morphologically different types of flowers tightly packed into a flower head (capitulum). Individual floral organs such as pappus bristles (sepals) are developmentally specialized, stamens are aborted in marginal flowers, petals and anthers are fused structures, and ovaries are located inferior to other floral organs. These specific features have made gerbera a rewarding target of comparative studies. Here we report the analysis of a gerbera EST database containing 16,994 cDNA sequences. Comparison of the sequences with all plant peptide sequences revealed 1656 unique sequences for gerbera not identified elsewhere within the plant kingdom. Based on the EST database, we constructed a cDNA microarray containing 9000 probes and have utilized it in identification of flower-specific genes and abundantly expressed marker genes for flower scape, pappus, stamen, and petal development. Our analysis revealed several regulatory genes with putative functions in flower-organ development. We were also able to associate a number of abundantly and specifically expressed genes with flower-organ differentiation. Gerbera is an outcrossing species, for which genetic approaches to gene discovery are not readily amenable. However, reverse genetics with the help of gene transfer has been very informative. We demonstrate here the usability of the gerbera microarray as a reliable new tool for identifying novel genes related to specific biological questions and for large-scale gene expression analysis.

First Cretaceous flowers from Antarctica

The present investigation was undertaken to study the floral morphology behavior among 22 genotypes of Jasminum sambac. Results revealed that among the different genotypes, cluster bearing habit in terminal position was recorded in genotypes Iruvatchi and IIHR JS - 5, whereas other genotypes recorded forked cymes of cluster flowers in terminal and axillary. Three different shapes of flower bud was recorded among the genotypes, viz. pointed and long, pointed and short, rounded and short. Flower bud colour and colour on flower bud opening was white (155 B or 155 C) and pink tinge on flower bud was recorded in IIHR JS - 5. Star and round shaped flower was observed among different genotypes. Three different types of flowers were recorded, viz., single, double and multi-whorled (3 to 6). Among 22 genotypes, Arka Aradhana recorded longest bud (3.85 cm) and corolla (2.11 cm). The genotype IIHR JS - 5 recorded the longest corolla tube (2.29 cm) and Iruvatchi recorded maximum number of forks per cyme (14). Maximum number of calyx lobe was recorded in Gundumallige (8.79 cm), whereas longest calyx lobe was recorded in Soojimalli (1.49 cm). Bigger size of flower was recorded in Soojimalli (4.64 cm) and maximum number of petals was observed in IIHR JS - 1 (40). The information generated on floral morphological traits in different genotypes will facilitate the planned crop improvement programmes in jasmine.

With few exceptions the flowers of plants belonging to the family Gramineae are small and have only a rudimentary perianth. In what follows the variation in floral structure within the family is described and it is shown that most of the known floral types may be derived by reduction from an Arundinariatype flower. A method for calculating the total possible range of variability is presented, and the numbers of known and theoretically possible flowers are compared for several different types of flowers. The consequences of floral evolution on the presentday reproductive mechanisms within the family is briefly discussed.

Floral development and evolution of capitulum structure in Anacyclus (Anthemideae, Asteraceae)

The subject of this research is Flemish painting the XVII century in the spiritual and cultural context of the Counter-Reformation, which created remarkable decorative and religious images to counter the iconoclastic trends of the Reformation movement. The object of this research is Flemish paintings of the Baroque Period of the XVII century with flower garlands edging the central image of Madonna. Special attention is given to the variety of iconographic patterns of the image of Virgin Mary framed in a flower garland, which was widely popular in painting of the Baroque period. Some artists use the pattern of “painting in a painting”; others imitate sculpture, the color of which accentuates the brightness of garlands. The article employs iconographic, iconological, and artistic methods, as well as stylistic analysis. The scientific novelty consists in proving the fact that Virgin Mary appears in painting not only as an individual image, but in paintings of flower garlands as well. The acquired results demonstrate that in the XVII centuries, the artists used different iconographic patterns for creating the image of Virgin Mary. The masters were able to combine different types of flowers, reaching the harmony of floral motifs and balancing them with the image of Madonna. The artists demonstrated the beauty of flower garlands by adding different living creatures in their paintings, such as birds and animals, to make them look more colorful, peaceful and vibrant. Thanks to these works, the image of Madonna remained extremely revered in the XVII century.

Fashion trends nowadays prefer synthetic dyes and fabrics in industry and these goods could not successfully connect environmentally friendly concepts with sustainability. As a substitution for synthetic dyes and fabrics, natural dyes, and fabrics can counter the existing problem by carrying out eco-print to minimize environmental pollution and risks to human health. Therefore, this study aims to explore the effect of eco-printing on three different types of fabrics (cotton, linen, and silk) by using three different types of flowers (Marigold, Cosmos, and Butterfly Pea). The Eco-print process was run by using the steaming method with different times taken to determine which time is the most appropriate to get a nice and clear print. This study focused on the colorfastness properties of eco-printed fabrics. These results were evaluated by performing color measurement and fastness tests towards washing and light referring to standard testing methods. As results, with the addition of Aluminium Potassium Sulphate mordants, the effect of eco-print of Marigold Flowers on silk fabric are the best results in fastness properties. The best time for steaming effect for eco-print in this study is 30 minutes. In terms of color measurement, it was discovered that mordants such Aluminium Potassium Sulphate enhance eco-print color on fabrics and provide the darkest colors which provided a colorfastness test with rating of moderate to good towards washing and light testing.

In cut flowers, xylem occlusion or blockage by bacteria negatively affects water balance and postharvest quality. Many studies have used culture-based methods to examine bacterial populations in vase water and their effects on flower longevity. It is still unclear if and how bacterial communities at the 16S rRNA gene (16S) level change during the vase period and how such change might correlate with postharvest longevity. This study compared the sequences of 16S amplicons from 4 different types of flowers and their vase water over the course of 7 days (Rosa spp., Gerbera jamesonii, and two Lilium varieties). The relative abundance of plant chloroplast and mitochondria 16S decreased significantly over the course 7 days in all 4 flowers as bacterial diversity increased. Richness and evenness of the bacterial communities increased over time, as did the number of rare taxa and phylogenetic diversity. Bacterial communities varied with time, as well as by flower source, types, and sample location (water, stem surface, whole stem). Some taxa, such as Enterobacteriacea and Bradyhizobiaceae decreased significantly over time while others such as Pseudomonas spp. increased. For example, Pseudomonas veronii, implicated in soft rot of calla lily, increased in both whole stem samples and water samples from Gerbera jamesonii. Erwinia spp., which includes plant pathogenic species, also increased in water samples. This work highlights the dynamic and complex nature of bacterial succession in the flower vase ecosystem. More work is needed to understand if and how bacterial community structure can be managed to improve cut flower vase life.

After a few weeks spent working in the hive, worker bees become foragers that leave the hive to gather nectar and pollen. Foraging--which requires the abilities to navigate, remember the way back to the hive, differentiate among different types of flowers, and communicate information--is accompanied by an increase in the size of the mushroom bodies, brain regions implicated in certain forms of learning and memory. Ismail et al. marked honeybees of known age that had begun foraging and, after a week spent foraging, either allowed them to continue foraging for a second week or confined them to cages or hives. Mushroom body volume in bees that had spent a second week foraging was larger than that of bees that had been confined. There were no differences in the mushroom body volume between bees that had foraged for a single week and those that had been caged for the second week, indicating that foraging during the second week stimulated mushroom body growth. Caged bees that ingested the muscarinic agonist pilocarpine underwent an increase in mushroom body volume comparable to that of those that spent a second week foraging, an effect that was not seen in other brain regions and was blocked by the muscarinic antagonist scopolamine. Thus, the authors conclude that muscarinic signaling mediates an experience-dependent structural change in the bee brain and that bees may provide an amenable system in which to investigate cholinergic mechanisms involved in experience-dependent plasticity of brain structure. N. Ismail, G. E. Robinson, S. E. Fahrbach, Stimulation of muscarinic receptors mimics experience-dependent plasticity in the honey bee brain. Proc. Natl. Acad. Sci. U.S.A. 103 , 207-211 (2006). [Abstract] [Full Text]

Pistacia chinensis Bunge, in China, holds an important role in economic, social and landscape benefits. This species is recorded to be a dioecious plant, with both staminate and pistillate inflorescence conical shaped. This study aimed to assess the different types of flowers and sexual types of P. Chinensis and to test the fertility of both male and female gametophytes. Results revealed for the first time the existence of monoecious trees in Tang County Hebei Province, China. Three types of inflorescences were found: staminate and pistillate inflorescences growing on different branches of the same tree; staminate and pistillate inflorescences growing on the same branch but belonging to different inflorescence buds; staminate and pistillate inflorescence formed from the same inflorescence bud. Four types of inflorescence were observed: staminate and pistillate flowers in single sex inflorescences, mixed inflorescences, hermaphrodite flowers, single-sex flowers and hermaphrodite flowers forming an inflorescence. Artificial crossings showed that pollen and ovary of monoecious types were fertile. Crossings between one male tree and monoecious trees used as female parents produced bigger fruits than those obtained when female tree was used as female parent. These preliminary results are of great importance for orchards establishment and should be further explored for their potential in breeding programmes.

It is a very hard and a challenging mission to identify different types of flowers as they are very similar. Even expert botanists and gardeners cannot identify some of them accurately. The idea of automating flowers recognition is bewildering as the flowers are not rigid objects and their images can be affected by many External influences. The proposed system use machine learning algorithms to fully automate and increase the accuracy of flower classification. Machine learning model will be used to extract flower’s features automatically, process through different layers of the neural network and finally classify the flower class. The proposed work is based on “Resnet” model, which is used for classification task. Resnet won the first place on ILSVRC 2015. Many enhancements have been made on Resnet model to improve the accuracy. Fine tuning, dropout ratio and class weight are some of the proposed model enhancements. The proposed model reaches 92% accuracy, which is the highest percent till the moment.

Over-expression of the Gerbera hybrida At-SOC1-like1 gene Gh-SOC1 leads to floral organ identity deterioration.

Abstract:The separation between monocot and dicot plants occurred about 120 ‐ 180 million years ago and since then major morphological changes have led to the striking differences that can be observed today. To understand whether, despite these differences, the processes controlling flower development are fundamentally comparable in dicot and monocot species, it is necessary to perform comparative studies. However, until recently flower development has been studied mainly in dicot plant species. Genetic and molecular analyses of two dicot model species,Arabidopsis thalianaandAntirrhinum majus,led to the formulation of the ABC model of flower development that describes how the combined activities of three classes of genes are required to drive flower organ development. This model has recently been extended by the inclusion of two other gene classes, namely D and E, which are involved in ovule development, and petal, stamen and carpel development, respectively. Most of the A, B, C, D and E genes identified so far have been shown to encode MADS‐box transcription factors. In rice a number of regulatory genes belonging to the MADS‐box transcription factor family have been cloned in the last few years and the functions of some of them have been investigated in detail. Here we review the current state of knowledge on rice flower development and focus on MADS‐box genes that determine floral organ identity in this species. We compare results obtained in rice with the information known forArabidopsisand the differences between these two species are discussed.

Cultivated gerbera daisies [ Gerbera hybrida ( G. jamesonii Bolus ex Adlam × G. viridifolia Schultz-Bip)] have several different flower types. They include single and crested cultivars that have normal florets with elliptical (ligulate) outer corolla lips and spider cultivars that have florets with laciniated (split) outer corolla lips appearing as several pointed lobes. The objective of this investigation was to determine the mode of inheritance of the major flower types of gerberas in the North Carolina State Univ. collection. The collection contained parents and four generations of progeny representing a wide range of single and crested cultivars and some spider cultivars. Genotypes of parents used in crosses were determined by testcrosses to single-flowered, ligulate floret cultivars similar in phenotype to the wild, parental gerbera species. Testcrosses indicated that the wild type was recessive to the crested and spider flower types and given the genotype crcrspsp . For each of the types, a series of crosses were made to produce P A , P B , F 1 , F 2 , BC 1A , and BC 1B progeny. Allelism was tested operationally by crossing genotypes in all possible combinations and observing single-gene-pair ratios. Linkage relationships among the crested and spider loci were tested using dihybrid crosses and testcrosses. Phenotypic segregation ratios suggested the presence of two dominant alleles, Cr d and Cr , determining the enlarged disk and trans floret, male-sterile and enlarged trans floret, male-fertile crested types, respectively, and an unlinked dominant gene, Sp , determining the spider type. Dominance appeared to be incomplete due to the reduction of trans floret length in most Cr d cr and Crcr heterozygotes compared to crested homozygotes and the appearance of the quasi-spider type (spider trans and disk florets and ligulate and/or slightly notched ray florets) among certain crested Spsp heterozygotes.