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Floating-leaved rhizophytes can significantly alter net carbon dioxide (CO2) and methane (CH4) exchanges with the atmosphere in freshwater shallow environments. In particular, CH4 efflux can be enhanced by the aerenchyma-mediated mass flow, while CO2 release from supersaturated waters can be reversed by the plant uptake. Additionally, the floating leaves bed can hamper light penetration and oxygen (O2) diffusion from the atmosphere, thus altering the dissolved gas dynamics in the water column. In this study, net fluxes of CO2 and CH4 were measured seasonally across vegetated [Nuphar lutea (L.) Sm.] and free water surfaces in the Busatello wetland (Northern Italy). Concomitantly, dissolved gas concentrations were monitored in the water column and N. lutea leaf production was estimated by means of biomass harvesting. During the vegetative period (May-August), the yellow water lily stand resulted a net sink for atmospheric carbon (from 97.5 to 110.6 g C-CO2 m-2), while the free water surface was a net carbon source (166.3 g C-CO2 m-2). Both vegetated and plant-free areas acted as CH4 sources, with an overall carbon release comprised between 71.6 and 113.3 g C-CH4 m-2. On the whole, water column chemistry was not affected by the presence of the floating leaves; moreover, no significant differences in CH4 efflux were evidenced between the vegetated and plant-free areas. In general, this study indicates that the colonization of shallow aquatic ecosystems by N. lutea might not have the same drastic effect reported for free-floating macrophytes. [ABSTRACT FROM AUTHOR]

Abstract: Here we report the effect of a partially purified alkaloid fraction (NUP) of Nuphar lutea on nuclear factor kappa B (NF-κB) expression and studied its mechanism of toxicity against Leishmania major in C3H mice peritoneal macrophages. NUP was found to be a mixture of thermo-stable dimeric sesquiterpene thioalkaloids containing mainly thionupharidines. The anti-leishmanial activity was shown to be mediated through the activation of NF-κB and increased iNOS production. Additionally, the nitric oxide inhibitor, NG-monomethyl-l-arginine (0.5mM) totally reverted the anti-leishmanial effect of NUP (0.25 and 0.5μg/ml). NUP was also shown to act as an anti-oxidant, almost completely inhibiting the macrophage respiratory burst activity. However, no elevated lysozyme (EC3.2.1.17) or β-galactosidase (EC3.2.1.23) activities were demonstrated in macrophages treated with NUP. This study suggests, that the activity of NUP is mediated by NF-κB activation and the production of nitric oxide which is dependent on the l-arginine:NO pathway. [ABSTRACT FROM AUTHOR]

Current understanding of floral developmental genetics comes primarily from the core eudicot model Arabidopsis thaliana. Here, we explore the floral transcriptome of the basal angiosperm, Nuphar advena (water lily), for insights into the ancestral developmental program of flowers. We identify several thousand Nuphar genes with significantly upregulated floral expression, including homologs of the well-known ABCE floral regulators, deployed in broadly overlapping transcriptional programs across floral organ categories. Strong similarities in the expression profiles of different organ categories in Nuphar flowers are shared with the magnoliid Persea americana (avocado), in contrast to the largely organ-specific transcriptional cascades evident in Arabidopsis, supporting the inference that this is the ancestral condition in angiosperms. In contrast to most eudicots, floral organs are weakly differentiated in Nuphar and Persea, with staminodial intermediates between stamens and perianth in Nuphar, and between stamens and carpels in Persea. Consequently, the predominantly organ-specific transcriptional programs that characterize Arabidopsis flowers (and perhaps other eudicots) are derived, and correlate with a shift towards morphologically distinct floral organs, including differentiated sepals and petals, and a perianth distinct from stamens and carpels. Our findings suggest that the genetic regulation of more spatially discrete transcriptional programs underlies the evolution of floral morphology. [ABSTRACT FROM AUTHOR]

Animals facilitate macrophyte seed dispersal in various ways despite specializations of macrophytes for water dispersal. Previous diet analyses of freshwater aquatic turtles revealed that several North American turtle species consume a variety and abundance of seeds among other plant material and animal prey. We quantified the dietary habits of Chrysemys picta picta (Eastern Painted Turtle) in a Massachusetts lake to examine if these animals included hydrophyte seeds in their diet and evaluate their capacity as passive seed-dispersal agents. Fifty-four turtles were trapped and housed to collect feces. Examination of feces revealed a diverse diet with comparatively high frequencies of animal, plant, and algal matter. Eight hundred fifty-seven seeds of at least nine plant species were egested (among 87% of turtles), with all but five (99%) seeds visibly intact. Seeds of Nuphar (473) and Decodon (305) were most abundant in the feces. Life-history characteristics of both C. p. picta and Nuphar suggest an effective endozoochorous seed dispersal association. [ABSTRACT FROM AUTHOR]

The conventional concept of an ‘undifferentiated perianth’, implying that all perianth organs of a flower are alike, obscures the fact that individual perianth organs are sometimes differentiated into sepaloid and petaloid regions, as in the early-divergent angiosperms Nuphar, Nymphaea, and Schisandra. In the waterlilies Nuphar and Nymphaea, sepaloid regions closely coincide with regions of the perianth that were exposed when the flower was in bud, whereas petaloid regions occur in covered regions, suggesting that their development is at least partly controlled by the environment of the developing tepal. Green and colourful areas differ from each other in trichome density and presence of papillae, features that often distinguish sepals and petals. Field experiments to test whether artificial exposure can induce sepalness in the inner tepals showed that development of sepaloid patches is initiated by exposure, at least in the waterlily species examined. Although light is an important environmental cue, other important factors include an absence of surface contact. Our interpretation contradicts the unspoken rule that ‘sepal’ and ‘petal’ must refer to whole organs. We propose a novel theory (the Mosaic theory), in which the distinction between sepalness and petalness evolved early in angiosperm history, but these features were not fixed to particular organs and were primarily environmentally controlled. At a later stage in angiosperm evolution, sepaloid and petaloid characteristics became fixed to whole organs in specific whorls, thus reducing or removing the need for environmental control in favour of fixed developmental control. [ABSTRACT FROM PUBLISHER]

The concentration of trace elements was studied in different parts of the submersed species Najas marina and Potamogeton lucens and in floating-leaved species Nuphar lutea and Potamogeton nodosus, and also in the corresponding samples of water and sediment in the artificial lake Velenjsko jezero, where the large amount of ash from lignite coal (about 15 million tons) is deposited at the bottom. The concentration of trace elements in water was mainly below the detection limit. In sediment only the concentration of As was found to be above the average European background concentration. It also showed the highest degree of translocation from sediment into plant roots, but its mobility to above-ground plant parts was negligible. The submersed species N. marina and P. lucens exhibited similar concentrations of trace elements in their organs. Of the floating-leaved species, the lowest concentrations of trace elements were found in N. lutea and the largest in P. nodosus. Significantly higher concentrations of As, Ni, Pb and Cr were shown in roots of N. marina, P. lucens and P. nodosus than in their stems and leaves, whereas Cu and Zn were equally distributed throughout all their organs. Cr and Ni also showed relatively high mobility from roots to upper parts of N. lutea. [Copyright &y& Elsevier]

Scanning electron microscopy (SEM) photographs of thick sections from liquid-preserved stems of Victoria cruziana and Euryale ferox show accretions of coarse fibrils on pit membranes of tracheids. The first-deposited fibrils are randomly orientated; on top of them (facing the tracheid lumina) are axially orientated coarse fibrils. The two systems are interconnected. Axially orientated fibrils were more extensively observed in Euryale than in Victoria and tips of fibrils in Euryale extend over the pit apertures onto secondary wall surfaces. Tracheid–parenchyma interfaces bear rudimentary coarse fibrils on the tracheid side. End walls of Victoria tracheids have highly porose pit membranes, thinner and less complex than those of the lateral intertracheid walls. The structures reported in Victoria and Euryale are consistent with those concurrently reported for stems of other Nymphaeaceae. Although also present in Cabombaceae, the coarse fibrils are otherwise not reported for stems of angiosperms and are not yet reported in roots of any species. Pit membrane remnants in perforation plates of various woody dicotyledons represent a nonhomologous phenomenon. The accretions of coarse fibrils in stem tracheids of Nymphaeaceae do not appear to enhance conduction, although they do contain porosities interconnecting tracheids. Removal of pit membrane remnants from perforation plates of primitive dicotyledon woods by hydrolysis does, on the contrary, suggest conduction enhancement. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159, 52–57. [ABSTRACT FROM AUTHOR]

SEM studies of xylem of stems of Nuphar reveal a novel feature, not previously reported for any angiosperm. Pit membranes of tracheid end walls are composed of coarse fibrils, densest on the distal (outside surface, facing the pit of an adjacent cell) surface of the pit membrane of a tracheid, thinner, and disposed at various levels on the lumen side of a pit membrane. The fibrils tend to be randomly oriented on the distal face of the pit membrane; the innermost fibrils facing the lumen take the form of longitudinally oriented strands. Where most abundantly present, the fibrils tend to be disposed in a spongiform, three-dimensional pattern. Pores that interconnect tracheids are present within the fibrillar meshwork. Pit membranes on lateral walls of stem tracheids bear variously diminished versions of this pattern. Pits of root tracheids are unlike those of stems in that the lumen side of pit membranes bears a reticulum revealed on the outer surface of the tracheid after most of the thickness of a pit membrane is shaved away by the sectioning process. No fibrillar texturing is visible on the root tracheid pits when they are viewed from the inside of a tracheid. Tracheid end walls of roots do contain pores of various sizes in pit membranes. These root and stem patterns were seen in six species representing the two sections of Nuphar, plus one intersectional hybrid, as well as in one collection of Nymphaea, included for purposes of comparison. Differences between root and stem tracheids with respect to microstructure are consistent in all species studied. Microstructural patterns reported here for stem tracheid pits of Nymphaeaceae are not like those of Chloranthaceae, Illiciaceae, or other basal angiosperms. They are not referable to any of the patterns reported for early vascular plants. The adaptational nature of the pit membrane structure in these tracheids is not apparent; microstructure of pit membranes in basal angiosperms is more diverse than thought prior to study with SEM. [ABSTRACT FROM AUTHOR]

For more than a century, the common ancestor of flowering plants was thought to have had a seven-celled, eight-nucleate Polygonum-type female gametophyte. It is now evident that not one, but in fact three, patterns of female gametophyte development and mature structure characterize the common ancestors of the four most ancient clades of extant angiosperms: Amborella-type, Nuphar/Schisandra-type and Polygonum-type. The Amborella-type female gametophyte is restricted to a single extant species, Amborella trichopoda, and at maturity consists of eight cells and nine nuclei. Development of the Amborella-type gametophyte is essentially identical to the Polygonum-type except that there is an additional and asynchronous cell division at the micropylar pole prior to maturation that produces a third synergid and the egg cell. The Nuphar/Schisandra-type female gametophyte is four-nucleate and four-celled and at maturity contains a typical three-celled egg apparatus and a central cell with a single haploid polar nucleus. This type of gametophyte appears to be universal among extant members of the Nymphaeales (including Hydatellaceae) and Austrobaileyales. Based on explicit reconstruction of character distribution and evolution, the Polygonum-type female gametophyte is certain to be representative of the common ancestors of monocots, eudicots, magnoliids, Ceratophyllaceae, and Chloranthaceae. There are compelling biological reasons to suggest that the four-celled, four-nucleate female gametophyte (as found in Nymphaeales and Austrobaileyales) is ancestral among angiosperms, with transitions to Polygonum-type female gametophytes separately in the Amborellales and in the ancient angiosperm clade that includes all angiosperms except Amborella, Nymphaeales, and Austrobaileyales. Subsequent to the evolution of a seven-celled, eight-nucleate Polygonum-type female gametophyte in the Amborellales, we hypothesize that a peramorphic increase in egg apparatus cell number took place and led to the unique situation in which there are three synergids in Amborella trichopoda. [ABSTRACT FROM AUTHOR]

Expressed sequence tags (ESTs) for the basal angiosperms Amborella trichopoda (Amborellaceae) and the water lily Nuphar advena (Nymphaeaceae) have proven valuable in identification of gene pairs to study the timing of duplication events relative to the most recent common ancestor (MRCA) of all extant angiosperms. Here we discuss how ESTs for these taxa are also useful for deducing gene families that were present in the MRCA of all flowering plants. For example, 4,572 gene clusters identified in an analysis of the rice and Arabidopsis proteomes contained putative orthologs of Amborella or Nuphar. Homologs of many developmentally important genes were identified from Amborella or Nuphar in these gene clusters. This number of ancestral genes is expected to increase as the number of Amborella and water lily ESTs increases. Genes found unduplicated in the rice and Arabidopsis genomes may be especially useful for phylogenetic analyses including diverse angiosperm lineages. We identify 595 of these single copy genes with putative orthologs in Amborella or Nuphar. Phylogenetic analysis of one of these nuclear single-copy genes encoding the enzyme carboxymethylenebutenolidase yields a topology that places Amborella and Nuphar as the sisters to all other extant lineages of angiosperms and is generally consistent with current angiosperm phylogenies based mainly on chloroplast, mitochondrial, and nuclear ribosomal sequences. [ABSTRACT FROM AUTHOR]

Heavy metal bioaccumulation and translocation properties of aquatic plants are interesting because of their potential use in phytoextraction. However, there is not enough knowledge about the seasonal changes of the metal distribution properties of aquatic plants. Our study focused on seasonal variation of some heavy metals in relation to their bioaccumulation and translocation in Nuphar lutea, a floating leaved, widespread plant that is important to wildlife. In this study, N. lutea, corresponding sediment and water samples were collected at different seasons from Lake Abant (Turkey) and analysed for their heavy metal content (Pb, Cr, Cu, Mn, Ni, Zn and Cd). Accumulation and translocation of heavy metal ratios were calculated seasonally. It was found that Cr and Zn were actively transported from sediment to the root, where they accumulated especially in summer; it was also shown that Cu, Mn and Zn were not only taken up from the sediment but also from the surrounding water. The investigations suggested that translocation ratios for leaf/root of Pb, Cr, Mn and Zn reached their highest levels in spring. It was found that the bioaccumulation and translocation of heavy metals at different parts of N. lutea changes with respect to season and the type of heavy metal. [ABSTRACT FROM AUTHOR]

1. River corridors are well-known for their role in plant dispersal. The buoyancy of seeds, the possibility of dispersal by vegetative fragments, and the frequency and efficiency of dispersal among different river catchments determine linear distribution patterns. Little is known about the relative importance of these factors to observed patterns of genetic variation. 2. One hundred and fifty-six Nuphar lutea individuals from forty-four sampling sites in the river catchments of the Cidlina River, the Mrlina River and the Labe River (Czech Republic) were studied using ten microsatellite markers. Interpretation of patterns in genetic variation allowed several conclusions about dispersal mechanisms. 3. Vegetative long-distance dispersal is probably very limited in this species. Only one multilocus genotype was found in more than one sampling site. The distance between the sites was about 75 km. 4. To explain the distribution of Bayesian based clusters of related multilocus genotypes, both along-river and inter-river long-distance dispersals have to be invoked. 5. A marginally significant tendency for higher genetic diversity in the lower part of the river Cidlina was detected. Continuous downstream dispersal of seeds by water currents could be a valid explanation. 6. Significant positive autocorrelation was found among individuals at within-river distances of up to 25 km. Repeated dispersal of seeds over distances in the range of tens of kilometers is common. [ABSTRACT FROM AUTHOR]

Recent phylogenetic analyses position Nuphar as the basalmost genus in the Nymphaeaceae, a member of the ANITA grade that is constituted of the three most basal angiosperm lineages [ Amborella, Nymphaeales, and Austrobaileyales (Austrobaileyaceae, Illiciaceae, Schisandraceae, and Trimeniaceae)]. In Nuphar the anther is tetrasporangiate. The endothecial cells elongate radially and develop fibrous thickenings. The glandular tapetum persists up to the two-celled pollen stage. Successive microsporogenesis results in the formation of tetrahedral and isobilateral microspore tetrads. Anasulcate pollen is two-celled when shed, with long stout echinae on the surface. A longitudinal ridge occurs in the center of the pollen furrow. The ovules are anatropous, bitegmic and crassinucellate. The inner integument arises as an annular ridge, whereas the outer one initiates as a semi-annular ridge interrupted on the concave side of the funiculus. Later the outer integument becomes a hood-shaped envelope. The micropyle structure is variable in various stages of ovule development. At anthesis the micropyle is formed by both integuments, while before and after anthesis it is formed by the inner integument. This contrasts with all previous reports, which state that the micropyle of Nuphar is formed by the inner integument alone throughout ovule development. Megasporogenesis forms a linear triad of megaspores. At the binucleate stage of female gametophyte ontogeny, the two nuclei are not separated by a large vacuole from the chalazal and micropylar ends. The wide distal region of stigma is covered with high density in unicellullar papillae whereas the narrow adaxial region has sparse unicellular papillae. The present study compares the reproductive morphological characters of Nuphar with those of other nymphaeaceous genera. [ABSTRACT FROM AUTHOR]

Abstract: The flower and fruit production of the yellow water lily Nuphar subintegerrima and the seasonal occurrence of the flower stalk-boring moth Neoschoenobia testacealis were surveyed in two irrigation ponds in western Japan. Water-level fluctuations at each pond were measured. Flowering was observed from late May to September, and fruiting from late May to October. The yellow water lily produced cumulative numbers of 189 and 181 flowers and 121 and 129 fruits in the two ponds’ quadrats. The fruit setting rates at the two ponds were 0.64 and 0.71, and decreased in the summer. The percentage of bored flower stalks was 16 and 5%. Mature larvae bored flower stalks severely during the summer. Whenever the boring larvae attacked the flower stalks, the flower buds and flowers were aborted. There was a significant negative correlation between the fruit setting rate and the boring rate per month (number of bored flower stalks/number of all flower stalks). Whenever abruptly rising water levels (about 10cm) submerged the flowers, the flowers were aborted too and could not set fruits. The percentages of non-setting fruit due to the rising water levels at the two ponds were 6 and 8%. Overall, our results indicated that flower stalk boring was a more important factor than water-level fluctuation in the sexual reproduction of N. subintegerrima and that N. subintegerrima was well suited to small irrigation ponds. [Copyright &y& Elsevier]

Trophic cascades may purportedly be more common in aquatic than terrestrial food webs, but herbivory on freshwater vascular plants has historically been considered low. Water lilies are an exception, suffering severe grazing damage by leaf beetles. To test whether a central prediction of cascade models—that predator effects propagate downwards to plants—operates in a macrophyte-based food web, we experimentally manipulated predation pressure on a key herbivore of water lilies in the littoral zone of a lake in Michigan, USA. Field experiments comprised combinations of caging treatments to alter the number of predators (larvae of the ladybird beetle Coleomegilla maculata) that hunt the grazers of the macrophytes (larvae of the leaf beetles Galerucella nymphaeae) on the leaves of the water lily Nuphar advena. Predatory larvae of the ladybird beetles significantly reduced grazing damage to water-lily leaves by 35–43%. The predators reduced plant damage chiefly via density-mediated effects, when lower densities of grazers translated to significant declines in plant damage. Plant damage caused by the surviving herbivores was less than predicted from individual grazing rates under predator-free conditions. This suggests that trait-mediated effects may possibly also operate in this cascade. The observed strong effect of predators on a non-adjacent trophic level concurs with an essential component of the trophic cascade model, and the cascade occurred at the ecotone between aquatic and terrestrial habitats: Nuphar is an aquatic macrophyte with emergent and floating leaves, whereas both beetle species are semi-terrestrial and use the dry, emergent and floating leaves of the water lily as habitat. Also, the cascade is underpinned by freshwater macrophytes—a group for which trophic processes have often been underappreciated in the past. [ABSTRACT FROM AUTHOR]

Anthesis in individual flowers of Nuphar pumila (Timm) DC. occurs for four consecutive days. First-day flowers are protogynous and functionally female. Flowers can open completely on the first day of anthesis. This contrasts with all previous reports, which state that first-day flowers of Nuphar are characterized by partial expansion of the calyx, leaving a distal small triangular opening just above the stigmatic disc. Flowers close completely on the first night of anthesis and remain partially open on the subsequent three nights. During the entire anthesis period the stigmas emit a sweet, fruity odor and the petal nectaries produce visible nectar drops. The stigma of N. pumila is secretory and unicellular-papillate. Pollen grains are monosulcate with long spines. Our observations on the mating system of N. pumila indicate that neither asexual seed production nor spontaneous self-pollination occurs. Cross-pollination of second-, third- and fourth-day flowers produced few seeds. Flowers of N. pumila were mainly pollinated by sweat bees, with flies playing a minor pollination role. No beetle visits were observed. Our insect-pollination observations substantiate the view that the relative contribution of flies, bees, and beetles to pollination in a single Nuphar population depends on two factors: the relative abundance of the insects, and presence of alternative food sources. [ABSTRACT FROM AUTHOR]

Susiea newsalemae Taylor, DeVore & Pigg gen. et sp. nov. is described for distinctive seeds referable to the water lily family Nymphaeaceae from the Late Paleocene Almont Flora of central North Dakota, U.S.A. Seeds are oval to barrel shaped, 5 mm long × 3 mm wide, and have an apical operculum and a prominent lateral raphe. The outer surface of the seeds is composed of palisade, shinglelike cells 40 µm high × 150 µm wide with smooth cell margins lacking papillae. The operculum is 1 mm across and surrounded by a narrow furrow, covering the micropyle but not the hilum. The raphe and micropyle are separated by several cells. Several specimens have a small embryo cavity surrounded by a small area of presumed endosperm below the micropyle and a well-developed perisperm filling the rest of the seed cavity. Susiea seeds are most similar to those of extant Euryale but differ in features of the epidermal cells, seed coat, and raphe morphology. They also share some features with Nymphaea, Nuphar, and Victoria. Susiea appears distinct from the permineralized fossil seeds of the middle Eocene Allenbya from the Princeton chert, Nuphar wutuensis from the Eocene of China, and Nuphar cf. wutuensis from the same Almont beds. Susiea is the oldest fossil taxon of the Euryale lineage, extending the previous Oligocene record back to the Late Paleocene and documenting a significantly older age for the Euryale/Victoria clade that is clearly a derived lineage based on phylogenetic analyses of modern taxa. [ABSTRACT FROM AUTHOR]

A developmental and anatomical study of the staminate flowers of Halophytum ameghinoi showed decussate tepal estivation; residual growth of the receptacle after stamen inception; monocotyledonous and basic types of anther wall development; secretory, binucleate tapetal cells; tetrahedral tetrads; and binucleate pollen grains. A vacuolate stage in the archesporial cells, the structure of endothecial thickenings, and a mechanism of anther dehiscence by connective contraction are new autapomorphies for this family. Anemophily is confirmed (Plantago-type syndrome), and field studies of pollen release showed a subtle mechanism involving rigid anther wall structure, versatile anther insertion, and abaxial subterminal pores. In air currents, while anthers flutter with pores directed upwind, pollen is extracted presumably by a cavitation effect of the hooded anther tip. In a phylogenetic context, anemophily of Halophytum is of isolated occurrence within Caryophyllales, and uniovulate ovaries in sister clades probably represent a prerequisite for evolution of anemophily. [ABSTRACT FROM AUTHOR]

Nymphaea and Nuphar (Nymphaeaceae) share an extra-axillary mode of floral inception in the shoot apical meristem (SAM). Some leaf sites along the ontogenetic spiral are occupied by floral primordia lacking a subtending bract. This pattern of flower initiation in leaf sites is repeated inside branching flowers of Nymphaea prolifera (Central and South America). Instead of fertile flowers this species usually produces sterile tuberiferous flowers that act as vegetative propagules. N. prolifera changes the meristem identity from reproductive to vegetative or vice versa repeatedly. Each branching flower first produces some perianth-like leaves, then it switches back to the vegetative meristem identity of the SAM with the formation of foliage leaves and another set of branching flowers. This process is repeated up to three times giving rise to more than 100 vegetative propagules. The developmental morphology of the branching flowers of N. prolifera is described using both microtome sections and scanning electron microscopy. [ABSTRACT FROM AUTHOR]

1. We investigated the importance of lake water chemistry and substrate properties in regulating microbial decomposer communities on macrophyte litter. Ten lakes of differing water chemistry, including such variables as nutrient concentration, pH and dissolved organic carbon, were sampled in October 2003. Water chemistry was analysed, and litter from the macrophytes Phragmites australis, Schoenoplectus lacustris and Nuphar lutea was collected from both above and below the water surface. 2. The three plant species differed widely in carbon and nitrogen content. The aerial parts of P. australis had highest C : N ratio (mean value 125), while the lowest values were found in leaves of N. lutea (19.8). 3. Fungal carbon ranged from 0.15 to 6.4 mg g−1 dry weight (DW), and was higher on aerial than on submerged plant parts. Fungal biomass was highest on S. lacustris and lowest on N. lutea. Denaturing gradient gel electrophoresis revealed no differences in the number of fungal taxa between plant species or plant parts, with the limitation that no molecular analysis was possible for N. lutea. 4. In contrast, bacteria were most abundant on N. lutea, but showed no significant difference between leaf and stem parts. The number of bacterial taxa was highest on the submerged parts of P. australis. 5. The correlations between microbial variables and the properties of lakes and litter were analysed using multivariate statistics. In a principal component analysis, litter properties explained 78% of the variation in microbial variables. In contrast, redundancy analysis revealed that the explanatory power of lake water chemistry was only 20%, indicating that the properties of the growth substratum were more important than those of the lake water for the attached microbial communities. [ABSTRACT FROM AUTHOR]

Abstract: The methanolic extract and its alkaloid fraction from the rhizomes of Nuphar pumilum showed cytotoxic effects on human leukemia cell (U937), mouse melanoma cell (B16F10), and human fibroblast (HT1080). Dimeric sesquiterpene thioalkaloids with the 6-hydroxyl group (6-hydroxythiobinupharidine, 6,6′-dihydroxythiobinupharidine, 6-hydroxythionuphlutine B) showed substantial cytotoxic activity at a concentration of 10μM, but dimeric sesquiterpene thioalkaloids lacking the 6-hydroxyl group (thiobinupharidine, thionuphlutine B, 6′-hydroxythionuphlutine B, neothiobinupharidine, thionuphlutine B β-sulfoxide, and neothiobinupharidine β-sulfoxide) and monomeric sesquiterpene alkaloids (nupharidine, 7-epideoxynupharidine, and nupharolutine) showed weak activity. Next, apoptosis-inducing activity of a principal active constituent, 6-hydroxythiobinupharidine, on U937 was examined using morphological observation and DNA fragmentation assay (TUNEL method). Apoptosis of U937 was immediately observed within 1 h after treatment of 6-hydroxythiobinupharidine at 2.5–10μM. [Copyright &y& Elsevier]

The ABC model of floral organ identity is based on studies of Arabidopsis and Antirrhinum, both of which are highly derived eudicots. Most of the genes required for the ABC functions in Arabidopsis and Antirrhinum are members of the MADS-box gene family, and their orthologs are present in all major angiosperm lineages. Although the eudicots comprise 75% of all angiosperms, most of the diversity in arrangement and number of floral parts is actually found among basal angiosperm lineages, for which little is known about the genes that control floral development. To investigate the conservation and divergence of expression patterns of floral MADS-box genes in basal angiosperms relative to eudicot model systems, we isolated several floral MADS-box genes and examined their expression patterns in representative species, including Amborella (Amborellaceae), Nuphar (Nymphaeaceae) and Illicium (Austrobaileyales), the successive sister groups to all other extant angiosperms, plus Magnolia and Asimina, members of the large magnoliid clade. Our results from multiple methods (relative-quantitative RT-PCR, real-time PCR and RNA in situ hybridization) revealed that expression patterns of floral MADS-box genes in basal angiosperms are broader than those of their counterparts in eudicots and monocots. In particular, (i) AP1 homologs are generally expressed in all floral organs and leaves, (ii) AP3/ PI homologs are generally expressed in all floral organs and (iii) AG homologs are expressed in stamens and carpels of most basal angiosperms, in agreement with the expectations of the ABC model; however, an AG homolog is also expressed in the tepals of Illicium. The broader range of strong expression of AP3/PI homologs is inferred to be the ancestral pattern for all angiosperms and is also consistent with the gradual morphological intergradations often observed between adjacent floral organs in basal angiosperms. [ABSTRACT FROM AUTHOR]

In this paper we describe the stereoselective synthesis of functionalized lactam 7 via two enantiospecific piperidine-forming techniques and its employment in a general synthetic approach to Nuphar alkaloids. Specifically, the formation of piperidine 18 by formal 113 + 3] cycloaddition and stepwise annelation processes is described; the latter technique was found to be significantly more efficient than the Pd-catalyzed TMM addition process. Finally, exploitation of the exocyclic alkene installed in the piperidine-forming reaction in the transformation of 18 to (-)-deoxy-nupharidine ((-)-2), (-)-castoramine ((-)-3), and (-)-nupharolutine ((-)-4) via intermediate lactam 7 is delineated. [ABSTRACT FROM AUTHOR]

To reveal the environmental and substrate quality effects on decomposition process and enzyme activities, litterbag experiments containingNupharandCarexleaves,Nupharrhizome, andRanunculusshoot, were carried in five-subalpine marshes in Lake Tahoe basin, USA. Alkaline phosphatase,ß-glucosidase, andß-xylosidase activities were determined by a fluorogenic method using methyumbelliferyl substrates.Carexleaves,Nupharrhizome and leaves, andRanunculusshoots lost, respectively, 33, 67, 82 and 93% of original dry weight over 268 days. Decay rates were different among substrates but not among marshes. Nitrogen and carbon contents increased during the first 58 days and subsequently remained stable. Phosphorus content was stable during the experimental period except for a decrease in the first 16 days inNupharshoots. Enzyme activities in decomposingCarexandNupharleaves in four marshes were not significantly affected by environmental conditions.ß-glucosidase andß-xylosidase activities in decomposingCarexleaves increased with time, but in other plant tissue these enzyme activities remained stable during experimental period. Enzyme activities were significantly different among decomposing substrates. Alkaline phosphatase activity was highest inNupharleaves (ca. 1286µ-mole h-1 g DW-1) but lower and similar in other plant tissues (ca. 100 and 10µ-mole h-1g DW-1, respectively). This study showed differences in decay rates and enzyme activities rely on substrate and not the environment conditions of the study area. Decomposition rates in the early stage of decomposition were related to cumulative enzyme activities. [ABSTRACT FROM AUTHOR]

Well-preserved seeds from the early Eocene of Wutu, Shandong, China are assigned to the genus Nuphar (Nymphaeaceae) based on morphology and anatomy. The seeds of Nuphar wutuensis sp. nov. are ellipsoidal to ovoid, 4–5 mm long with a clearly visible raphe ridge, and a truncate apex capped by a circular operculum ca. 1 mm in diameter bearing a central micropylar protrusion. These features, along with the testa composed of a uniseriate outer layer of equiaxial pentagonal to hexagonal surface ceils and a middle layer 4–6 cells thick composed of thick-walled, periclinally elongate sclereids, correspond to the morphology and anatomy of extant Nuphar and distinguish this fossil species from all other extant and extinct genera of Nymphaeales. These seeds provide the oldest record for the genus in Asia and are supplemented by a similar well-preserved specimen from the Paleocene of North Dakota, USA. These data, together with the prior recognition of Brasenia (Cabombaceae) in the middle Eocene, indicate that the families Nym- phaeaceae and Cabombaceae had differentiated by the early Tertiary. [ABSTRACT FROM AUTHOR]

1. Most studies of plant palatability do not consider its seasonal variability, and infer general life-history patterns from single-date feeding experiments. This paper investigates whether different seasonal patterns in the palatability of perennial plant species in one community can alter their relative susceptibility to grazing. 2. The palatability ot eight freshwater macrophyte species growing at the same site was monitored during 1 year through nine consecutive feeding experiments using a generalist consumer, the pond snail Lymnaea stagnalis. 3. Plant palatability varied significantly throughout the year and reached its maximum in autumn Beyond this general trend, seasonal patterns in palatability differed markedly between species, and two (callitriche platycarpa and Nuphar lutea) showed no significant seasonal variations. 4. Despite the interspecific differences in seasonal patterns of palatability, species palatability rankings remained stable throughout the year Therefore feeding experiments performed at a single sampling date are suitable to assess the relative palatability of a set of species. [ABSTRACT FROM AUTHOR]

Phenotypic responses of Potamogeton amplifolius and Nuphar advena to different light (7% and 35% of surface irradiance) and nutrient environments were assessed with field manipulation experiments. Higher light and nutrient availability enhanced the growth of P. amplifolius by 154% and 255%, respectively. Additionally, biomass was allocated differently depending on the resource: high light availability resulted in a higher root/shoot ratio, whereas high nutrient availability resulted in a lower root/shoot ratio. Low light availability and high nutrient availability increased the nitrogen content of leaf tissue by 53% and 40% respectively, resulting in a 37% and 31% decrease in the C/N ratio. Root nitrogen content was also increased by low light and high nutrient availability, by 50% (P=0.0807) and 77% respectively, resulting in a 20% and 40% decrease in root C/N ratio. Leaf phenolics were significantly increased 72% by high light and 31% by high nutrient availability, but root phenolic concentrations were not altered significantly. None of these changes in tissue constituents resulted in altered palatability to crayfish. N. advena was killed by the same high nutrient treatment that stimulated growth in P. amplifolius, preventing assessment of phenotypic responses to nutrient availability. However, high light availability increased overall growth by 24%, but this was mainly due to increased growth of the rhizome (increased 100%), resulting in a higher root/shoot ratio. High light tended to increase the production of floating leaves (P=0.09) and significantly decreased the production of submersed leaves. High light availability decreased the nitrogen content by 15% and 25% and increased the phenolic concentration by 88% and 255% in floating and submersed leaves, respectively. These differences in leaf traits did not result in detectable differences in damage by herbivores. [ABSTRACT FROM AUTHOR]

Previous taxonomic assessments of the hydrophytic genus Nuphar Sm. (Nymphaeaceae) have inadequately considered the range of morphological variation existing in the genus. A comprehensive statistical analysis of morphological features among the recognized taxa of Nuphar is presented here, first using 10 fruit characters to delimit the separation of two infrageneric groups of taxa, and secondly using 31 characters to quantify the morphological variation found within sect. Nuphar. Results from combined phenetic analyses provided empirical support for recognition of two infrageneric groups of species in the genus (largely by fruit, stigmatic disk margin, neck, and stigmatic disk size) and for separation of taxa within sect. Nuphar (by leaf size, and fruit disk and neck size). Statistical analyses demonstrate that extensive variation in ranges of character states exists among sect. Nuphar taxa. However, a suite of qualitative and quantitative characters can be used to recognize five species and three subspecies within this predominantly Old World assemblage. [ABSTRACT FROM AUTHOR]

Presents a study which tested the effect of natural variations in environmental conditions on leaf types developed by yellow waterlily Nuphar variegata Durand. Cause of heterophylly in plants; Materials and methods used; Effects of sediment type on the plant; Patterns of leaf production.

To assess the effect of water depth on the decomposition process, I measured the losses in dry mass of the above- and belowground materials of Carex utriculata and Nuphar luteum ssp. potysepalum as well as cellulose (Whatman filter paper) in the top 10 cm of sediment/soil in a subalpine marsh. Samples were examined by the litter bag technique at three flooding levels (0 to 5, 60, and 100 cm water depth). Over a 374-d period, the % mass losses of cellulose, Carex leaves and roots, and Nuphar leaves and rhizomes ranged from 98.5 to 99.0, 74.8 to 81.8, 36.3 to 44.9, 95.8 to 97.7, and 78.4 to 91.5%, respectively. Rates for cellulose decay in this study were much higher than for samples from other wetlands; this difference resulted from the location of the litter bag (in the top 10 cm of soil vs in the water column). Water depth significantly affected the decomposition of Carex roots and Nuphar rhizomes. The rate of loss for K was highest in all tissues of Carex and Nuphar, followed by Na in Carex and P in Nuphar. N and Ca loss rates generally were low. The C/N ratio tended to converge to a common value over the long term. This convergence has an important implication in the paleoecological interpretation of the C/N ratio change in sediment; i.e., this ratio shift in the sediment core results from a change in the environment, rather than the source material. [ABSTRACT FROM AUTHOR]

Presents a study which investigated pollination in Nuphar ozarkana and Nuphar advena to assess whether there is evidence of pollinator shifts associated with floral-morphological differences between Old World and New World species. Materials and methods used; Results and discussion.

Rhodium-catalyzed enantioselective addition of aryl and heteroaryl boron pinacol esters to pyridinium and quinolinium salts is developed for the synthesis of enantioenrichred dihydroheteroarenes. The methodology has enabled the synthesis of 2-heteroaryl-substituted dihydropyridines in high yield and ee, which provided efficient synthetic access to a nuphar alkaloid.

The specificity of inhibition by 6,6′-dihydroxythiobinupharidine (DTBN) on cysteine proteases was demonstrated in this work. There were differences in the extent of inhibition, reflecting active site structural-steric and biochemical differences. Cathepsin S (IC50 = 3.2 μM) was most sensitive to inhibition by DTBN compared to Cathepsin B, L and papain (IC50 = 1359.4, 13.2 and 70.4 μM respectively). DTBN is inactive for the inhibition of Mpro of SARS-CoV-2. Docking simulations suggested a mechanism of interaction that was further supported by the biochemical results. In the docking results, it was shown that the cysteine sulphur of Cathepsin S, L and B was in close proximity to the DTBN thiaspirane ring, potentially forming the necessary conditions for a nucleophilic attack to form a disulfide bond. Covalent docking and molecular dynamic simulations were performed to validate disulfide bond formation and to determine the stability of Cathepsins-DTBN complexes, respectively. The lack of reactivity of DTBN against SARS-CoV-2 Mpro was attributed to a mismatch of the binding conformation of DTBN to the catalytic binding site of Mpro. Thus, gradations in reactivity among the tested Cathepsins may be conducive for a mechanism-based search for derivatives of nupharidine against COVID-19. This could be an alternative strategy to the large-scale screening of electrophilic inhibitors. [ABSTRACT FROM AUTHOR]

Describes the novel pathway to the enantioselective synthesis of nuphar alkaloids. Total synthesis of (-)-(5S,8R,9S)-5-(3-furyl)-8-methyloctahydroindolizidine; Total synthesis of (-)-nupharamine; Asymmetric synthesis of piperidine and indolizidine alkaloids; Precursors of piperidine alkaloids; Formation of derivatives with other aromatic rings.

Investigates the phylogenetic relationships in Nuphar using morphology and sequences of the chloroplast gene matK and of the internal transcribed spacer (ITS) regions of nuclear ribosomal DNA. Characters and character states used in the phylogenetic analysis of Nuphar morphology; List of sources of plant materials used in the phylogenetic analysis of DNA nucleotide sequence of Nuphar; Discordance among phylogenies.

Studies the roots of Nuphar, Nymphaea and Ondinea with SEM in order to determine presence of perforations in end walls of tracheary elements. Presence of perforations in Nuphar, Nymphaea and Ondinea; Commonality of striations in primary walls of tracheary elements in all three genera.

(1) Aquatic vegetation growing under, or emerging from, dry-weather water level along 5 km of the River Roding, near Abridge, Essex, was monitored during 1979-82 to assess floristic changes following two-stage channel construction. (2) Aquatic plant communities remained stable in the absence of river engineering. (3) In-channel vegetation cover, species richness and diversity were maintained when the undisturbed lowermost portion of river was incorporated into a two-stage channel. (4) Vegetation cover increased for at least 2 years after flood berm excavation. Species richness increased in the short-term but subsequently declined as invasive species., notably Sparganium erectum L., proliferated. Sagittaria sagittifolia L. and Sparganium emersum Rehmann rapidly became more abundant in the short-term but Nuphar lutea (L.) Sm. and Schoenoplectus lacustris (L.) Palla responded slowly and declined in relative abundance. (5) Increased light and reduced scour along the channel edge created ideal conditions for the growth of tall emergent vegetation, and S. erectum, Phragmites australis (Cav.) Trin ex Steudel and Typha latifolia L. proliferated along reaches bordered by low-level flood berms, in particular. (6) Two-stage channel construction is ecologically preferable to channelization but appropriate measures to counter excessive vegetation growth must be incorporated if the short-tern benefits are to be maintained in the longer term. [ABSTRACT FROM AUTHOR]

Focuses on a study which devoted multivariate analyses of morphology, pollen fertility studies, and random amplified polymorphic deoyriboncleic acid (DNA) (RAPD) markers for the testing of the hypothesis that Nuphar X rubrodisca (Nymphaeaceae) represents. What does Nuphar X rubrodisca represents; Details on the study; Methods and materials used in the study, including an RAPD analysis; Results of the study.

Focuses on the effects of leaf surface wetness on gas exchange in the pond lily Nuphar polysepalum. Susceptibility of leaf surface to dewfall; Reduction of photosynthesis in wet leaves; Reasons for temperature variation of floating Nuphar leaves.