Recruitment of an ancient branching program to suppress carpel development in maize flowers

Carpels in maize undergo programmed cell death in half of the flowers initiated in ears and in all flowers in tassels. The HD-ZIP I transcription factor gene GRASSY TILLERS1 (GT1) is one of only a few genes known to regulate this process. To identify additional regulators of carpel suppression, we performed a gt1 enhancer screen and found a genetic interaction between gt1 and ramosa3 (ra3). RA3 is a classic inflorescence meristem determinacy gene that encodes a trehalose-6-phosphate (T6P) phosphatase (TPP). Dissection of floral development revealed that ra3 single mutants have partially derepressed carpels, whereas gt1;ra3 double mutants have completely derepressed carpels. Surprisingly, gt1 suppresses ra3 inflorescence branching, revealing a role for gt1 in meristem determinacy. Supporting these genetic interactions, GT1 and RA3 proteins colocalize to carpel nuclei in developing flowers. Global expression profiling revealed common genes misregulated in single and double mutant flowers, as well as in derepressed gt1 axillary meristems. Indeed, we found that ra3 enhances gt1 vegetative branching, similar to the roles for the trehalose pathway and GT1 homologs in the eudicots. This functional conservation over ∼160 million years of evolution reveals ancient roles for GT1-like genes and the trehalose pathway in regulating axillary meristem suppression, later recruited to mediate carpel suppression. Our findings expose hidden pleiotropy of classic maize genes and show how an ancient developmental program was redeployed to sculpt floral form.

Recruitment of an ancient branching program to suppress carpel development in maize flowers

Floral morphology is immensely diverse. One developmental process acting to shape this diversity is growth suppression. For example, grass flowers exhibit extreme diversity in floral sexuality, arising through differential suppression of stamens or carpels. In maize, carpels undergo programmed cell death in half of the flowers initiated in ears and in all flowers in tassels. The HD-ZIP I transcription factor gene GRASSY TILLERS1 (GT1) is one of only a few genes known to regulate this process. To identify additional regulators of carpel suppression, we performed a gt1 enhancer screen, and found a genetic interaction between gt1 and ramosa3 (ra3). RA3 is a classic inflorescence meristem determinacy gene that encodes a trehalose-6-phosphate (T6P) phosphatase (TPP). Dissection of floral development revealed that ra3 single mutants have partially derepressed carpels, whereas gt1; ra3 double mutants have completely derepressed carpels. Surprisingly, gt1 suppresses ra3 inflorescence branching, revealing a role for gt1 in meristem determinacy. Supporting these genetic interactions, GT1 and RA3 proteins colocalize to carpel nuclei in developing flowers. Global expression profiling revealed common genes misregulated in single and double mutant flowers, as well as in derepressed gt1 axillary meristems. Indeed, we found that ra3 enhances gt1 vegetative branching, similar to the roles for the trehalose pathway and GT1 homologs in the eudicots. This functional conservation over ~160 million years of evolution reveals ancient roles for GT1-like genes and the trehalose pathway in regulating axillary meristem suppression, later recruited to mediate carpel suppression. Our findings expose hidden pleiotropy of classic maize genes, and show how an ancient developmental program was redeployed to sculpt floral form.

Testing Pollination Syndromes in Oenothera (Onagraceae)

Pollinators are considered a major selective force in shaping the diversification of angiosperms. It has been hypothesized that convergent evolution of floral form has resulted in “pollination syndromes” - i.e. suites of floral traits that correspond to attraction of particular pollinator functional groups. Across the literature, the pollination syndrome concept has received mixed support. This may be due to studies using different methods to describe floral traits and/or the pollination syndrome concept being supported more often in species highly reliant on pollinators for reproduction. Here, we assess the predictive ability of pollination syndromes in Oenothera, a species rich clade with pollination systems existing on a gradient of specialization, and in which species are either self-compatible or self-incompatible. We ask the following questions: Do Oenothera species follow the pollination syndrome concept using traditional, categorical floral trait descriptions and/or quantitative floral trait measurements? And, are floral traits more predictive of primary pollinators in species with specialized pollination systems and/or species that are self-incompatible? Mapping floral traits of 54 Oenothera species into morphospace, we do not find support for the pollination syndrome concept using either categorical or quantitative floral trait descriptions. We do not find support for specialization or breeding system influencing the prediction of primary pollinators. However, we find pollination syndromes were more predictive in Oenothera species with moth pollination systems. Collectively, these results suggest that the pollination syndrome concept cannot be generally applied across taxa and that evolutionary history is important to consider when evaluating the relationship between floral form and contemporary pollinators.

Nymphaea kakaduensis (Nymphaeaceae), a new species from the northern portion of the Northern Territory, Australia

Nymphaea kakaduensis C.B.Hellq., A.Leu & M.L.Moody (Nymphaeaceae) is described from Kakadu National Park, Northern Territory. This new species is endemic to the “Top End” of the Northern Territory and was formerly included in N. violacea Lehm. The distinct floral form of N. kakaduensis of having generally smaller flowers with blunt-tipped petals and different coloration than N. violacea instigated a genetic study of taxa from the region. The cpDNA trnL (UAA) - trnF (GAA) intergenic spacer region was sequenced from samples from across northern Australia and a haplotype network analysis was conducted. Plants from populations that had the distinct floral form of N. kakaduensis are found to be genetically distinct from N. violacea in northern Australia sharing 4 SNPs and a notable 23 bp indel in the cpDNA intergenic spacer region to support the morphological attributes and species designation.

The Turnera Style S-Locus Gene TsBAHD Possesses Brassinosteroid-Inactivating Activity When Expressed in Arabidopsis thaliana

Heterostyly distinct hermaphroditic floral morphs enforce outbreeding. Morphs differ structurally, promote cross-pollination, and physiologically block self-fertilization. In Turnera the self-incompatibility (S)-locus controlling heterostyly possesses three genes specific to short-styled morph genomes. Only one gene, TsBAHD, is expressed in pistils and this has been hypothesized to possess brassinosteroid (BR)-inactivating activity. We tested this hypothesis using heterologous expression in Arabidopsis thaliana as a bioassay, thereby assessing growth phenotype, and the impacts on the expression of endogenous genes involved in BR homeostasis and seedling photomorphogenesis. Transgenic A. thaliana expressing TsBAHD displayed phenotypes typical of BR-deficient mutants, with phenotype severity dependent on TsBAHD expression level. BAS1, which encodes an enzyme involved in BR inactivation, was downregulated in TsBAHD-expressing lines. CPD and DWF, which encode enzymes involved in BR biosynthesis, were upregulated. Hypocotyl growth of TsBAHD dwarfs responded to application of brassinolide in light and dark in a manner typical of plants over-expressing genes encoding BR-inactivating activity. These results provide empirical support for the hypothesis that TsBAHD possesses BR-inactivating activity. Further this suggests that style length in Turnera is controlled by the same mechanism (BR inactivation) as that reported for Primula, but using a different class of enzyme. This reveals interesting convergent evolution in a biochemical mechanism to regulate floral form in heterostyly.

Evolutionary variation in MADS-box dimerization affects floral development and protein stability

Shifting interactions between MADS-box transcription factors may have been critical in the emergence of the flower, and in floral diversification. However, how evolutionary variation in MADS-box interactions affects the development and evolution of floral form remains unknown. Interactions between B-class MADS-box proteins are variable across the grass family. Here, we test the functional consequences of this evolutionary variability using maize as an experimental system. We found that differential B-class dimerization was associated with subtle, quantitative differences in stamen shape. In contrast, differential dimerization resulted in large-scale changes to protein complex composition and downstream gene expression. Differential dimerization also affected B-class complex abundance, independent of RNA levels. Thus, differential dimerization may affect protein stability. This reveals an important consequence for evolutionary variability in MADS-box interactions, adding complexity to the evolution of developmental gene networks. Our results show that floral development is robust to molecular change, even coding change in a master regulator of development. This robustness may contribute to the evolvability of floral form.

GUSTAV KLIMT’S CREATIVITY AND ITS IMPACT ON XX CENTURY FASHION

Secessionism from the beginning of the XX century offered a new option for the creation and interpretation of art through a unique individual expression of the artist that was the result of the coming changes in society. Gustav Klimt, one of the most striking representatives of Viennese secessionism, with his lifestyle and style of creation through combining techniques, has made changes in art, not always accepted in every segment, but with long-term consequences for the development of art and fashion. In a fashion sense, Klimt presented not only a new artistic expression but also paved the way of a modern contemporary woman. He was breaking social frames and norms, which was a link to the emerging fashion of the new age inevitably. The work was created with the idea of a brief overview and analysis of Gustav Klimt's creative work with elements of influence on the development of novelties in the design of clothing from the beginning, but also in the last decades during the XX century, from clothing, textile design to fashion accessories. Essential elements such as decorative ornaments and their combination through a combination of cold and warm colors enriched with gold tones have become authentic motifs imbued with the warmth of floral form and the mystique of geometrization.

Rehydration rates and the prevalence of xylem-hydration of flowers

Angiosperm flowers are remarkably diverse anatomically and morphologically, yet they all must satisfy the physiological constraints of supplying sufficient amounts of water and carbon effectively promote pollination. Flowers often occur in the hottest, driest parts of the plant canopy and can face harsh abiotic conditions. Prior evidence suggests that extant species vary dramatically in how water is delivered to flowers, with some evidence that water may be imported into flowers by the phloem. Here we measured midday water potential gradients between flowers, leaves, and stems often phylogenetically diverse species. We further tested the likelihood of xylem-hydration by measuring rates of rehydration after experimentally induced desiccation. There was no significant difference in rehydration rates between leaves and flowers. These results are consistent with xylem-hydration of flowers and suggest that there has been little modification to the mechanisms of water transport despite the diversity of floral form.

Heterochronic Developmental Shifts Underlie Floral Diversity within Jaltomata (Solanaceae)

BackgroundHeterochronic shifts during mid to late stages of organismal development have been proposed as key mechanisms generating phenotypic diversity. To determine whether late heterochronic shifts underlie derived floral morphologies within Jaltomata (Solanaceae) – a genus whose species have extensive and recently evolved floral diversity – we compared floral development of four diverse species (including an ambiguously ancestral or secondarily derived rotate, two putatively independently evolved campanulate, and a tubular morph) to the ancestral rotate floral form, as well as to an outgroup that shares this ancestral floral morphology.ResultsWe determined that early floral development (<1 mm bud diameter, corresponding to completion of organ whorl initiation) is very similar among all species, but that different mature floral forms are distinguishable by mid-development (>1 mm diameters) due to differential growth acceleration of corolla traits. Floral ontogeny among similar mature rotate forms remains comparable until late stages, while somewhat different patterns of organ growth are found between species with similar campanulate forms.ConclusionsOur data suggest shared floral patterning during early-stage development, but that different heterochronic shifts during mid- and late-stage development contributes to divergent floral traits. Heterochrony thus appears to have been important in the rapid and repeated diversification of Jaltomata flowers.

UNSUR KOMBINASI PADA VISUALISASI RAGAM HIAS BATIK KLASIK SEMÈN GAYA YOGYAKARTA

Semèn motifs on classical batik of Yogyakarta style, is a motif which visualize floral form withvarious elements motifs on it. Semèn motifs influenced Hindu-Java and Islamic culture. Influencefrom Islamic culture delivere a few motifs in stylization. From visual aspect, some of elementsmotifs on it visualize combine motifs. It become visual concept characteristic in Islam art includein semèn motifs on classical batik of Yogyakarta style. Visualization of motifs can be hide withcombined elements motifs. Keywords: semèn motifs, Yogyakarta classical batik, combine motifs