Helleborus
Plant traits, environmental factors, and pollinator visitation in winter-flowering Helleborus foetidus (Ranunculaceae). (1/7)
BACKGROUND AND AIMS: This study examined the effect of plant traits and environmental factors on pollinator visitation in the winter-flowering Helleborus foetidus (Ranunculaceae) in three distant regions in the Iberian Peninsula. METHODS: Geographical variation in floral visitor assemblage, plant traits and environmental factors were analysed during the flowering season. KEY RESULTS: Differences were found in all plant traits measured (number of open flowers, flower size, number of stamens per flower, and number of nectaries) both within and among regions, and differences among regions in all the environmental factors considered (air temperature, exposure to sunlight, canopy cover, and distance to the nearest neighbour). Differences were also found among regions in the probability that plants would be visited by pollinators. CONCLUSIONS: The results show that, although floral display (i.e. number of open flowers on a plant on a given day) consistently explained among-plant differences in visitation rate in all regions, visitation rate was not significantly affected by any other biological or environmental variable. In Helleborus foetidus, then, 'how' the plant is would seem to be more important than 'where' is it. (+info)Cytokinins in the perianth, carpels, and developing fruit of Helleborus niger L. (2/7)
Reproductive development in the Christmas rose (Helleborus niger L.) differs from that in commonly investigated model plants in two important aspects: (i) the perianth develops a photosynthetic system, after fertilization, and persists until seed ripening; and (ii) the ripe seed contains an immature embryo which continues to mature off the mother plant. The possible roles of cytokinins in these processes are investigated here by analysing extracts of the perianth and the carpels/maturing fruit prepared during anthesis and four stages of post-floral development. trans-Zeatin, dihydrozeatin, N6-(Delta2-isopentenyl)adenine, and their ribosides were identified by tandem mass spectrometry. Single ion monitoring in the presence of deuterated internal standards demonstrated the additional presence of the corresponding riboside-5'-monophosphates, O-glucosides, and 9-glucosides, and afforded quantitative data on the whole set of endogenous cytokinins. Fruit cytokinins were mostly localized in the seeds. Their overall concentrations increased dramatically during early seed development and remained high for 6-8 weeks, until shortly before seed ripening (the last time point covered in this work). Overall cytokinin levels in the perianth did not change markedly in the period covered, but the level of N6-(Delta2-isopentenyl)adenine-type cytokinins appeared to increase slightly and transiently during the greening phase. The perianths of unpollinated or depistillated flowers, which survived, but did not pass through the complete greening process, contained significantly less cytokinins than observed in fruit-bearing flowers. This suggests that perianth greening requires defined cytokinin levels and supports the role of the developing fruit in their maintenance. (+info)Synchrony between fruit maturation and effective dispersers' foraging activity increases seed protection against seed predators. (3/7)
The evolution of pollination and seed dispersal mutualisms is conditioned by the spatial and temporal co-occurrence of animals and plants. In the present study we explore the timing of seed release of a myrmecochorous plant (Helleborus foetidus) and ant activity in two populations in southern Spain during 2 consecutive years. The results indicate that fruit dehiscence and seed shedding occur mostly in the morning and correspond to the period of maximum foraging activity of the most effective ant dispersers. By contrast, ant species that do not transport seeds and/or that do not abound near the plants are active either before or after H. foetidus diaspores are released. Experimental analysis of diet preference for three kinds of food shows that effective ant dispersers are mostly scavengers that readily feed on insect corpses and sugars. Artificial seed depots suggest that seeds deposited on the ground out of the natural daily time window of diaspore releasing are not removed by ants and suffer strong predation by nocturnal rodents Apodemus sylvaticus. Nevertheless, important inter-annual variations in rodent populations cast doubts on their real importance as selection agents. We argue that traits allowing synchrony between seed presentation and effective partners may constitute a crucial pre-adaptation for the evolution of plant-animal mutualisms involving numerous animal partners. (+info)Substance MCS-18 isolated from Helleborus purpurascens is a potent antagonist of the capsaicin receptor, TRPV1, in rat cultured sensory neurons. (4/7)
Extracts of Helleborus roots were traditionally used in the Balkan area for their analgesic action. We report that the pure natural product MCS-18 isolated from this source is a potent, specific and reversible antagonist of the capsaicin receptor, TRPV1, expressed in rat dorsal root ganglion (DRG) neurons. TRPV1 is a non-selective cation channel expressed in a subset of cutaneous and visceral sensory nerve endings and activated by noxious heat, acidity and fatty acid metabolites of arachidonic acid, with a decisive role in inflammatory heat hyperalgesia. MCS-18 inhibited the increase in intracellular calcium concentration evoked in DRG neurons by capsaicin (300 nM) and low pH (5.5) but not by heat (43 degrees C). The substance had no effect on the responses mediated by acid-sensing ion channels (ASICs) or the irritant receptor TRPA1. Whole-cell patch-clamp was used to confirm the inhibition of capsaicin-induced currents by MCS-18 which was dose-dependent. The mechanism of inhibition does not require an intact cell, as capsaicin-induced currents were also inhibited in the excised outside-out configuration. The antagonism of the capsaicin and proton action on native TRPV1 by MCS-18 may be of interest for pain therapy. (+info)Presence of yeasts in floral nectar is consistent with the hypothesis of microbial-mediated signaling in plant-pollinator interactions. (5/7)
Olfactory floral signals are significant factors in plant-pollinator mutualisms. Recently, unusual fermentation odors have been described in the nectar and flowers of some species. Since yeasts are common inhabitants of many angiosperms nectars, this raises the possibility that nectar yeasts may act as causal agents of fermentation odors in flowers and, therefore, as possible intermediate agents in plant signaling to pollinators. A recent field study has reported that nectar yeasts were quite frequent in floral nectar across three different regions in Europe and America, where they reached high densities (up to 10(5) cells/mm(3)). Yeast incidence in floral nectar differed widely across plant host species in all sampling sites. A detailed study currently in progress on one of the species surveyed in that study (Helleborus foetidus, Ranunculaceae) has detected that, in addition to interespecific differences in yeast incidence, there is also a strong component of variance in yeast abundance that takes place at the subindividual level (among flowers of the same plant, among nectaries of the same flower). If yeast metabolism is eventually proved to contribute significantly to floral scent, then multilevel patchiness in the distribution of nectar yeasts (among species, among individuals within species, and among flowers and nectaries of the same individual) might contribute to concomitant multilevel variation in plant signaling and, eventually, also in pollination success, pollen flow and plant fitness. (+info)Nectar yeasts warm the flowers of a winter-blooming plant. (6/7)
(+info)Epigenetic differentiation persists after male gametogenesis in natural populations of the perennial herb Helleborus foetidus (Ranunculaceae). (7/7)
(+info)Helleborus, also known as Black Hellebore or Christmas Rose, is a genus of poisonous herbaceous perennial plants native to Europe and Northern Africa, containing several medicinally important alkaloids, used primarily in historical medicine for treating heart conditions and mental disorders, but now largely replaced by safer and more effective treatments.
'Helleborus' is a genus of herbaceous flowering plants in the family Ranunculaceae, also known as Hellebores or Christmas Roses. While these plants have been used in traditional medicine, it's important to note that many parts of Helleborus species are toxic and can cause serious health issues if ingested or handled improperly.
The use of Helleborus in modern medicine is limited due to its toxicity. However, some compounds derived from these plants have shown potential medicinal properties, such as anti-inflammatory, analgesic, and cardiovascular effects. More research is needed to determine their safety and efficacy before they can be used clinically.
In a medical context, referring to 'Helleborus' would typically involve discussing its toxicity, potential medicinal applications, or possible side effects from accidental ingestion or misuse.
Ranunculaceae, also known as the buttercup family, is a group of primarily herbaceous flowering plants characterized by having mostly basal leaves, often with palmate venation, and showy flowers with numerous free stamens and carpels, including notable genera such as Ranunculus, Delphinium, and Aconitum.
Ranunculaceae is a family of flowering plants, also known as the buttercup family. It includes over 2,000 species distributed across 58 genera. The plants in this family are characterized by their showy, often brightly colored flowers and typically have numerous stamens and carpels. Many members of Ranunculaceae contain toxic compounds, which can be irritants or even poisonous if ingested. Examples of plants in this family include buttercups, delphiniums, monkshood, and columbines.