A light in the shadow: the use of Lucifer Yellow technique to demonstrate nectar reabsorption

Abstract Background Nectar reabsorption is a widely known phenomenon, related to the strategy of resource-recovery and also to maintain the nectar homeostasis at the nectary. The method currently performed to demonstrate nectar being reabsorbed involves the use of radioactive tracers applied to the nectary. Although this method works perfectly, it is complex and requires specific supplies and equipment. Therefore, here we propose an efficient method to obtain a visual demonstration of nectar reabsorption, adapting the use of Lucifer Yellow CH (LYCH), a fluorescent membrane-impermeable dye that can enter the vacuole by endocytosis. Results We applied a LYCH solution to the floral nectary (FN) of Cucurbita pepo L., which is a species known for its ability of nectar reabsorption, and to the extrafloral nectary (EFN) of Passiflora edulis Sims which does not reabsorb the secreted nectar. In all tests performed, we observed that LYCH stained the nectary tissues differentially according to the reabsorption ability of the nectary. The treated FN of C. pepo presented a concentrated fluorescence at the epidermis that decreased at the deeper nectary parenchyma, until reaching the vascular bundles, indicating nectar reabsorption in the flowers of the species. In contrast, treated EFN of P. edulis presented fluorescence only at the cuticle surface, indicating that nectar is not reabsorbed by that particular tissue. Conclusion LYCH is an efficient marker to demonstrate nectar reabsorption.The authors thank the Pró-Reitoria de Pesquisa of the University of São Paulo for the help with the cost of the publishing. PCG and JMRBVA thank the grant provided by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). The authors thank the staff of Instituto de Botânica for providing assistance with cultivated material of P. edulis and Joel Caitano (Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto) for providing material of C. pepo. PCG also thank Wilton José da Rocha Lima (Central Analítica – Instituto de Química, Universidade de São Paulo) for technical assistance with confocal microscopy. JMRBVA thanks Laura de Castro Lamonica for helping with practical work. FB acknowledges the research productivity grant received from the Brazilian National Council for Scientific and Technological Development (CNPq). We thank the two anonymous referees for their valuable comments to the manuscript and their constructive suggestions.The authors thank the PróReitoria de Pesquisa of the University of São Paulo for the help with the cost of the publishing. PCG and JMRBVA thank the grant provided by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). The authors thank the staff of Instituto de Botânica for providing assistance with cultivated material of P. edulis and Joel Caitano (Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto) for providing material of C. pepo. PCG also thank Wilton José da Rocha Lima (Central Analítica – Instituto de Química, Universidade de São Paulo) for technical assistance with confocal microscopy. JMRBVA thanks Laura de Castro Lamonica for helping with practical work. FB acknowledges the research productivity grant received from the Brazilian National Council for Scientific and Technological Development (CNPq). We thank the two anonymous referees for their valuable comments to the manuscript and their constructive suggestions

Course and predictors of supportive care needs among Mexican breast cancer patients:A longitudinal study

Objective: This study examined the course and predictors of supportive care needs among Mexican breast cancer patients for different cancer treatment trajectories. Methods: Data from 172 (66.4% response rate) patients were considered in this observational longitudinal study. Participants were measured after diagnosis, neoadjuvant treatment, surgery, adjuvant treatment, and the first post-treatment follow-up visit. Psychological, Health System and Information, Physical and Daily Living, Patient Care and Support, Sexual, and Additional care needs were measured with the Supportive Care Needs Survey (SCNS-SF34). Linear mixed models with maximum-likelihood estimation were computed. Results: The course of supportive care needs was similar across the different cancer treatment trajectories. Supportive care needs declined significantly from diagnosis to the first post-treatment follow-up visit. Health System and Information care needs were the highest needs over time. Depressive symptoms and time since diagnosis were the most consistent predictors of changes in course of supportive care needs of these patients. Conclusions: Health system and information care needs of Mexican breast cancer patients need to be addressed with priority because these needs are the least met. Furthermore, patients with high depressive symptoms at the start of the disease trajectory have greater needs for supportive care throughout the disease trajectory

Evidence of trimonoecy in Phyllanthaceae: Phyllanthus acidus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Pollen from staminate flowers and pistillate flowers with "staminodes" of Phyllanthus acidus Skeels were analyzed under scanning electron microscopy, and tests of pollen viability and in vitro germination were carried out to verify possible similarities between the three types of flowers. The results show that pistillate flowers with "staminodes" are bisexual, indicating the occurrence of trimonoecy in this species.29641732283286Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [05/59543-7

Colleters in monocots: New record for Orchidaceae

Colleters are widely occurring in eudicots showing relevant taxonomic importance in several families. Nevertheless, there are few records in monocots, restricted to only one description of these glands in Orchidaceae. The genus Oncidium is polyphyletic, currently the subject of taxonomic studies. In this context, the secretory structures can be an important diagnostic character that may help in the delineation of this group. O. flexuosum Sims presents colleters in vegetative - leaf primordium of protocorms, apical and axillary buds in the mature rhizomes - and reproductive organs - at the base of bracts, bracteoles and sepals. All the colleters observed are finger-like trichomes, composed of two uniseriated cells, where the apical one is elongated and possesses dense cytoplasm. The exsudate accumulates in a subcuticular space. causing displacement of the cuticle. Histochemical tests indicate the presence of mucilage in association with lipophilic and proteinic compounds inside the secretory cell. Secretion is abundant, hyaline and slightly viscous. The localization of the trichomes and their exsudate indicate the involvement of these colleters with the protection of meristematic regions in vegetative and reproductive organs. These results can be useful in the taxonomy of the genus Oncidium and for future studies about colleters in monocots. (C) 2010 Elsevier GmbH. All rights reserved.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico - CNP

Unidirectional transitions in nectar gain and loss suggest food deception is a stable evolutionary strategy in Epidendrum (Orchidaceae): insights from anatomical and molecular evidence

Abstract Background Nectar gain and loss are important flower transitions observed in angiosperms, and are particularly common in orchids. To understand such transitions, the availability of detailed anatomical data and species-level phylogenies are crucial. We investigated the evolution of food deception in Epidendrum, one of the largest orchid genera, using genus phylogeny to map transitions between nectar gain and loss among different clades. Associations between anatomical and histochemical changes and nectar gain and loss were examined using fresh material available from 27 species. The evolution of nectar presence/absence in Epidendrum species was investigated in a phylogenetic framework of 47 species, using one nuclear and five plastid DNA regions available from GenBank and sequenced in this study. Results The presence or absence of nectar was strongly associated with changes in the inner epidermal tissues of nectaries. Nectar-secreting species have unornamented epidermal tissue, in contrast to the unicellular trichomes found on the epidermis of food deceptive species. Bayesian tests confirmed that transitions occurred preferentially from nectar presence to nectar absence across the Epidendrum phylogeny. In addition, independent nectar loss events were found across the phylogeny, suggesting a lack of constraint for these transitions. Conclusions Ornamented nectaries may play an important role in the deceptive pollination strategy by secreting volatile organic compounds and providing tactile stimuli to pollinators. The recurrent and apparently irreversible pattern of nectar loss in Epidendrum suggests that food deception may constitute an alternative evolutionarily stable strategy, as observed in other orchid groups

Evolution of connective glands reveals a new synapomorphy for Malpighiaceae and the hidden potential of staminal glands for Malpighiales systematics

Connective glands are important morphological characters for the taxonomy of some genera of Malpighiaceae, with few recent studies having just elucidated these glands' anatomical and ecological functions. In order to test the systematic relevance of connective glands to the currently accepted phylogenetic informal clades of Malpighiaceae, we characterised the anatomy and/or histochemistry of two-thirds of Malpighiaceae genera and ten species from nine families of Malpighiales to test: 1. Do connective glands occur in the flowers of all informal clades of Malpighiaceae?; and 2. Are they taxonomically relevant to characterise those clades? We sampled 25 genera and 26 species of Malpighiaceae, processing their anthers using traditional anatomical methods and characterising their glands using light microscopy and SEM imaging. Selected species were subjected to histochemical tests, and an additional 21 genera and 33 species of Malpighiaceae and nine families (ten species) of Malpighiales were included in our sampling from the literature. Three anatomical characters were scored, coded and mapped using Maximum Likelihood methods onto the molecular phylogeny of Malpighiaceae. All sampled species of Malpighiaceae showed connective glands characterised as epidermal or trichomal elaiophores. Our character-mapping analyses recovered connective elaiophores as a new synapomorphy for Malpighiaceae. Different types of epidermal or trichomal elaiophores were recovered as homoplasies for the Christianella and Banisteriopsis clades and the genera Byrsonima, Camarea and Cottsia. Our analyses also recovered the glands' place of insertion in the stamen and the exudate type as potential new synapomorphies or homoplasies for the families of Malpighiales sampled. Our results propose the connective elaiophores as a new synapomorphy for Malpighiaceae and hypothesise the role that different staminal glands might play in the systematics of Malpighiales. Further comprehensive anatomical studies are still needed for the staminal glands of most families of this order to shed new light on the patterns recovered in our study

Volatiles released by damaged leaves of piper mollicomum (piperaceae) act as cues for predaceous wasps : evidence using plasticine dummies as herbivore model

Volatiles released by damaged plants are used as cues by predators and parasitoids to find their herbivorous prey. Here, we assessed whether odor cues released by simulated herbivore-damaged leaves in Piper mollicomum attract predaceous wasps. We applied plasticine dummy caterpillars as an herbivore model to evaluate predation risk on undamaged and artificially damaged leaves by the mandible marks left by foraging wasps. Despite observing a tendency of a visual component in the wasp attraction (more marks on dummies under old naturally damaged leaves), we observed that chemical cues play a crucial role, with recent artificial damage and leaves baited with volatile essential oils of P. mollicomum attracting more wasps for the dummies than those untreated. Headspace analysis by GC–MS showed that undamaged leaves released small amounts of compounds, while damaged ones released 63 times more volatiles, which consisted of a blend containing mostly mono- and sesquiterpenoids. Histochemical tests revealed that terpenoids are located in oil cells spread among the leaf tissue, and may be released by the disruption of such cells when herbivores are feeding on leaves. We suggest that signals of disrupted plants differ from the mosaic of odor blends emitted by the background environment and may provide a detectable, although not necessarily specific, cue for prey presence. Such detectable cues are important for generalist foraging predaceous wasps, since they spend time searching for prey in different host plants134593601CNPQ - Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paulo304969/2006-098/01065-7We thank the Prefeitura Municipal de Jundiai (SP, Brazil) for the permission to work at the Serra do Japi. We also thank Martin Pareja and Daniela Rodrigues for kindly helping in part of the field work, Daniela Rodrigues and Alexander Christianini for their valuable comments in the early version of the manuscript. This work was supported by Grants to JRT (Fundação de Amparo à Pesquisa do Estado de São Paulo—FAPESP 98/01065-7 and Conselho Nacional de Desenvolvimento Científico e Tecnológico—CNPq 304969/2006-0

Strong but permeable barriers to gene exchange between sister species of Epidendrum

The investigation of reproductive barriers between sister species can provide insights into how new lineages arise, and how species integrity is maintained in the face of interspecific gene flow. Different pre- and postzygotic barriers can limit interspecific gene exchange in sympatric populations, and different sources of evidence are often required to investigate the role of multiple reproductive isolation (RI) mechanisms