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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 10 microM, but dimeric sesquiterpene thioalkaloids lacking the 6-hydroxyl group (thiobinupharidine, thionuphlutine B, 6'-hydroxythionuphlutine B, neothiobinupharidine, thionuphlutine B beta-sulfoxide, and neothiobinupharidine beta-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 2.5-10 microM.

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 [3 + 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 (−)-deoxynupharidine ((−)-2), (−)-castoramine ((−)-3), and (−)-nupharolutine ((−)-4) via intermediate lactam 7 is delineated.

The B-class MADS-box genes composed of APETALA3 ( AP3) and PISTILLATA ( PI) lineages play an important role in petal and stamen identity in previously studied flowering plants. We investigated the diversification of the AP3-like and PI-like MADS-box genes of eight species in five basal angiosperm families: Amborella trichopoda (Amborellaceae); Brasenia schreberi and Cabomba caroliniana (Cabombaceae); Euryale ferox, Nuphar japonicum, and Nymphaea tetragona (Nymphaeaceae); Illicium anisatum (Illiciaceae); and Kadsura japonica (Schisandraceae). Sequence analysis showed that a four amino acid deletion in the K domain, which was found in all previously reported angiosperm PI genes, exists in a PI homologue of Schisandraceae, but not in six PI homologues of the Amborellaceae, Cabombaceae, and Nymphaeaceae, suggesting that the Amborellaceae, Cabombaceae, and Nymphaeaceae are basalmost lineages in angiosperms. The results of molecular phylogenetic analyses were not inconsistent with this hypothesis. The AP3 and PI homologues from Amborella share a sequence of five amino acids in the 5' region of exon 7. Using the linearized tree and likelihood methods, the divergence time between the AP3 and PI lineages was estimated as somewhere between immediately after to several tens of millions of years after the split between angiosperms and extant gymnosperms. Estimates of the age of the most recent common ancestor of all extant angiosperms range from approximately 140-210 Ma, depending on the trees used and assumptions made.

[reaction: see text] A stereocontrolled route to Nuphar alkaloids is described that employs a formal [3 + 3] cycloaddition strategy to assemble the piperidine nucleus. The addition of Pd-TMM complexes to aziridine 10 was found to be sluggish; however, the addition of a functionalized allyl Grignard reagent followed by a Mitsunobu condensation reaction provided 11 in high yield. The employment of this route in the formal synthesis of (-)-deoxynupharidine 1 is described.

Knolrot in waterlelie is een algemeen voorkomend probleem, dat soms ineens voor veel uitval kan zorgen. Het uitgangsmateriaal is duur en daarnaast is oppotten en uitplanten behoorlijk arbeidsintensief. Ernstige uitval zorgt daarom voor een aanzienlijke kostenpost. Voor bestrijding van knolrot in waterlelie is het allereerst van belang de veroorzaker te vinden. Aanvankelijk werd vermoed dat een bepaalde schimmel verantwoordelijk was voor de ziekte, echter dat bleek niet het geval. Uit het onderzoek kwamen aanwijzingen dat een bacterie mogelijk een rol speelt, maar ook dat kon niet worden aangetoond. Uit de inventarisatie in het project Consultancy (nr. 312000) in 2002/2003 kwam naar voren dat knolrot mogelijk tijdens de bewaring (transport) ontstaat.

Knolrot in waterlelie is een algemeen voorkomend probleem, dat soms ineens voor veel uitval kan zorgen. Het uitgangsmateriaal is duur en daarnaast is oppotten en uitplanten behoorlijk arbeidsintensief. Ernstige uitval zorgt daarom voor een aanzienlijke kostenpost. Voor bestrijding van knolrot in waterlelie is het allereerst van belang de veroorzaker te vinden. Aanvankelijk werd vermoed dat een bepaalde schimmel verantwoordelijk was voor de ziekte, echter dat bleek niet het geval. Uit het onderzoek kwamen aanwijzingen dat een bacterie mogelijk een rol speelt, maar ook dat kon niet worden aangetoond. Uit de inventarisatie in het project Consultancy (nr. 312000) in 2002/2003 kwam naar voren dat knolrot mogelijk tijdens de bewaring (transport) ontstaat.

Four mesocosms were exposed to circumneutral and aluminum (Al)-rich wastewater during two successive summers (2000, 2001). The goals of the study were to measure the bioaccumulation of dissolved Al by the aquatic plants Typha latifolia , Lemna minor , Nuphar variegatum and Potamogeton epihydrus , and to evaluate their importance in the retention of Al by the mesocosms. In 2000, inlet concentrations of total monomeric Al were reduced by 56% and 29% at the Arvida and Laterriere mesocosms, respectively, whereas in 2001 inlet dissolved Al concentrations in the inlet decreased by 40% and 33%. L. minor had the highest Al uptake rate (0.8–17 mg Al g −1 d −1 ). However, because T. latifolia (cattails) yielded the highest biomass, it was responsible for 99% of the Al uptake, largely in its root tissue. In 2001, Al uptake by macrophytes accounted for 2–4% and 15–54% of the total Al retained by the Laterriere and Arvida mesocosms, respectively. In the Laterriere mesocosms, Al uptake by cattails could account for 12% and 18% of the dissolved Al retained by both mesocosms. In contrast, dissolved Al was not significantly reduced in the Arvida enclosures, yet cattails did accumulate Al in their roots. Further research is needed to identify the species community composition that would optimize dissolved Al retention.

The omnivorous crayfish Procambarus clarkii fed selectively on several species of macrophytes, preferring delicate fresh plants that had filamentous or finely-branched architectures. When the macrophytes were dried, powdered, and reconstituted into an alginate gel (thus eliminating among-species differences in physical characteristics). crayfish preferences were altered; previously tough plants that were high in nitrogen and protein were preferred over previously delicate plants that were low in nitrogen and protein. Even though plant structure influences feeding decision of crayfish, the structurally identical macrophyte gels were fed upon differently, demonstrating that nonstructural traits are important feeding determinants. However, plant tissue constituents such as nitrogen, protein, phenolics, lignin, cellulose, or ash were not significantly con-elated with feeding preferences. Two high-nitrogen plants that were avoided by crayfish as fresh and as reconstituted tissue (Nuphar luteum macrophyllum and Alternanthera philoxeroides) possessed extracts that reduced crayfish feeding in laboratory assays, demonstrating that macrophyte metabolites can deter some herbivores. As is often observed with large generalist herbivores and omnivores in terrestrial and marine systems, the freshwater crayfish made feeding decisions based upon multiple plant cues (structure, nutrition, chemical defenses).

Nuphar comprises 13 species of aquatic perennials distributed in the temperate Northern Hemisphere. The European species N. lutea and N. pumila in Norway, the Netherlands, and Germany are pollinated by bees and flies, including apparent Nuphar specialists. This contrasts with reports of predominant beetle pollination in American N. advena and N. polysepala. We studied pollination in N. ozarkana in Missouri and N. advena in Texas to assess whether (1) there is evidence of pollinator shifts associated with floral-morphological differences between Old World and New World species as hypothesized by Padgett, Les, and Crow (American Journal of Botany 86: 1316-1324. 1999) and (2) whether beetle pollination characterizes American species of Nuphar. Ninety-seven and 67% of flower visits in the two species were by sweat bees, especially Lasioglossum (Evylaeus) nelumbonis. Syrphid fly species visiting both species were Paragus sp., Chalcosyrphus metallicus, and Toxomerus geminatus. The long-horned leaf beetle Donacia piscatrix was common on leaves and stems of N. ozarkana but rarely visited flowers. Fifteen percent of visits to N. advena flowers were by D. piscatrix and D. texana. The beetles' role as pollinators was investigated experimentally by placing floating mesh cages that excluded flies and bees over N. advena buds about to open and adding beetles. Beetles visited 40% of the flowers in cages, and flowers that received visits had 69% seed set, likely due to beetle-mediated geitonogamy of 1st-d flowers. Experimentally outcrossed 1st-d flowers had 62% seed set, and open-pollinated flowers 76%; 2nd-d selfed or outcrossed flowers had low seed sets (9 and 12%, respectively). Flowers are strongly protogynous and do not self spontaneously. Flowers shielded from pollinators set no seeds. A comparison of pollinator spectra in the two Old World and three New World Nuphar species studied so far suggests that the relative contribution of flies, bees, and beetles to pollen transfer in any one population depends more on these insects' relative abundances (and in the case of Donacia, presence) and alternative food sources than on stamen length differences between Old World and New World pond-lilies.

Electron ionization of sulphur-containing Nuphar alkaloids leads to the formation of easily detectable, doubly-charged species. The study of charge-separation reactions by collision experiments allows us to determine the intercharge distances. These experimental figures agree well with the different stereochemistries of the compounds under investigation.

Concentrations of heavy metals (Ni, Cr, Co, Zn, Mn, Pb, Cd, Cu, Hg, Fe) as well as macronutrients (P, Ca, Mg) were measured in water, bottom sediments, and plants of three lakes in West Poland (southwest of Poznan). The plants collected were Nymphaea alba, Nuphar luteum, Ceratophyllum demersum, Phragmites communis, Typha latifolia, and Schoenoplectus lacustris. These plants contained elevated levels of Co, Zn, Pb, Cd, Cr, and Hg. Analyses of water and bottom sediments indicated that the lakes were polluted with Zn, Cd, Cu, and Pb and partly with Ni and Hg. Strong positive correlations were found between concentrations of Cd in water and in plants, between concentrations of Cd in bottom sediments and in plants, between concentrations of Cr in water and in plants, between concentrations of Cr in bottom sediments and in plants, and between concentrations of Fe in water and in plants, indicating the potential of plants for pollution monitoring for these metals. A negative correlation was found between biomass production and Pb and Mn content in water and Pb and Mn content in bottom sediments. Cr and Cd accumulated in plants at a higher rate from bottom sediments than from water. The accumulation rate of Fe in plant tissues was higher with an increase in Fe in water than with an increase in Fe in bottom sediments.

Potent immunosuppressants, the dimeric sesquiterpene thioalkaloids, 6-hydroxythiobinupharidine (2), 6, 6'-dihydroxythiobinupharidine (3), 6-hydroxythionuphlutine B (5) and 6'-hydroxythionuphlutine B (6), were isolated from a natural medicine, Nupharis Rhizoma, the rhizoma of Nuphar pumilum (TIMM.) DC., through bioassay-guided separation together with five quinolizidine alkaloids (8, 9, 10, 11, 12). Dimeric sesquiterpene thioalkaloids (2, 3, 5, 6) were found to significantly inhibit anti-sheep erythrocyte plaque forming cell formation in mice spleen cells at 10-6 M concentration. At this concentration, 2, 5 and 6 were found to exhibit no cytotoxicity to mice spleen cells, and 3 also showed only a little cytotoxicity. In addition, the inhibitory activity of several Nuphar alkaloids, dimeric sesquiterpene thioalkaloids (1, 4, 7, 8), and monomeric sesquiterpene alkaloids (9, 10, 11, 12) on anti-sheep erythorocyte plaque forming cell formation was examined and some structural requirement of Nuphar alkaloid for immunosuppressive activity was determined.

α- and β (or γ)-Tocopherols esterified with saturated monocarboxylic acids ranging from C12 to C18 were identified for the first time in the flowers and the leaves of Nuphar luteum and in the leaves and the stems of Nymphea alba using high temperature GC-FID and GC-MS mass fragmentography.

Apsilops japonicus n. sp. is described from Japan. This species parasitizes an aquatic crambid moth, Neoschoenobia testacealis Hampson, a petiole borer of the yellow water lily, Nuphar subintegerrimum (Casp.) Makino sensu lato. A key to the world species of Apsilops is provided.

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.

With the present study we attempt to elucidate the history of the order Nymphaeales¯water-lilies and relatives¯in time and space. On the basis of a dense taxon sampling that covers all genera ofCabombaceae and Nymphaeaceae and all subgenera of the genus Nymphaea, and on the basis of well-supported phylogenetic hypotheses, we estimate divergence times in Nymphaeales. Distribution data for all species are used to reconstruct ancestral ranges and to identify possible dispersal events in the biogeographic history of Nymphaeales. Considering the fossil record for the clade as well as geologic history, a plausible historical scenario can be drawn. The assessment of extant biogeography shows that there are several centres of species diversity for Nymphaeales, i.e., northern South America, Central America, the Zambezian region of Africa and northern Australia. However, the diversification of the Nymphaeales started in the Northern Hemisphere when the northern landmasses were covered by tropical vegetation, except for the very high latitudes. The estimation of divergence times depicted two distinct radiation events, a rapid first differentiation into three major lineages during the Paleocene (Cabombaceae, Nuphar, remaining Nymphaeaceae) and the radiation of core Nymphaeaceae (Victoria, Euryale, Nymphaea incl. Ondinea) from the Late Oligocene to Middle Miocene. The second radiation probably started in the Northern Hemisphere. We hypothesize that subsequent spatial separation and southward relocation of the descendants led to the disjunct distribution of extant sister lineages in core Nymphaeaceae, e.g., Euryale-Victoria or Nymphaea subgg. Hydrocallis and Lotos.

The grazing effects of the waterlily beetle Galerucella nymphaeae on Nuphar lutea stands were studied in three ponds in Central Finland. Production of floating leaves of N. lutea and growth in the G. nymphaeae population were investigated in the ponds and bioenergetics of the beetle larvae in the laboratory. Combination of field and laboratory data enabled estimation of the effect of the beetle on the production of floating leaves of N. lutea and the consequences of grazing for the input of detritus from Nuphar into the ponds. Adults and larvae of G. nymphaeae consumed 3.0–6.1% of the net annual floating leaf production during the growing period. In addition to consumption losses, feeding accelerated the degradation rate of the leaves. This was associated with an increased flow of detrital material of Nuphar origin, and also with increased production of floating leaves in the ponds. These increments were estimated to be up to 3 times greater in the presence of grazing than without it. Grazing by G. nymphaeae releases substantial amounts of carbon and nitrogen bound in Nuphar, particularly in ponds with a dense Nuphar vegetation. It is hypothesized that feeding by this beetle may markedly affect the structure and functioning of such small aquatic systems.

Asian clam Corbicula fluminea, the amphipod Dikerogammarus villosus and the macrophyte Nuphar lutea were tested for investigating spatial and temporal variability in the bioavailability of tin and arsenic in the River Lippe, Germany. Samples were collected from September 2002 to May 2003 at a tin polluted site (source pollution) and a reference site. Additional screening sampling was carried out twice in April 2003 to test the extent of As and Sn concentration in periphyton (aufwuchs) samples. Accumulated Sn and As concentrations were measured with ICP-MS after sample processing (dissection, cryo-milling) and digestion. Quality control was performed by parallel analysis of three certified reference materials. Measurable As and Sn contents in plant tissues were only detectable in roots (below 30 microg kg(-1) and 20 microg kg(-1) for As and Sn, respectively). Homogenates from C. fluminea and D. villosus tissues showed site-dependent trace metal contents. Elevated bioavailability of Sn is present downstream of the sewage discharge of the world's biggest producer of tributyltin (TBT) at Luenen (northern Ruhr region). In comparison to C. fluminea, D. villosus shows higher concentrations of tin in samples from both sites. Arsenic concentrations in C. fluminea remain constant with increasing shell size, whereas tin shows a size-dependent accumulation. The results indicate that Corbicula fluminea and Dikerogammarus villosus are suitable passive biomonitoring organisms for Sn, but As levels might be actively regulated. The concentration of tin in the periphyton (aufwuchs) samples was found to be much higher in samples from a contaminated site (428 +/- 63 vs. 1949 +/- 226 microg kg(-1)).

This review covers the isolation, structure determination, synthesis, chemical transformations and biological activity of indolizidine and quinolizidine alkaloids. Included in the review are the hydroxylated indolizidines lentiginosine, swainsonine, castanospermine and their analogues; alkaloids from animal sources, including ants, amphibians and beetles; indolizidine alkaloids from the genera Polygonatum, Prosopis and Elaeocarpus; indolizidine and phenanthroindolizidine alkaloids; alkylquinolizidine alkaloids, including myrtine, epimyrtine, plumerinine and Lycopodium metabolites; Lythraceae and Nuphar alkaloids; lupine alkaloids; and alkaloids from marine sources. 150 references are cited.

The 13C n.m.r. spectra of nine Nuphar alkaloids: deoxynupharidine, 7-epideoxynupharidine, nupharidine, 7-epinupharidine, nupharolutine, 7-epinupharolutine, thiobinupharidine, thionu-phlutine B, and neothiobinupharidine, have been determined. Also examined were the spectra of five model compounds, 2,2,4,4-tetramethylthiolane, 3(a)-methyl-3(e)-methylthiomethylquinolizidine, 3(e)-methyl-3(a)-methylthiomethylquinolizidine, 3(e)-methylthio-3(a)-methylquinolizidine, and 3-methylfuran. This latter group of spectra were used to assist the chemical shift assignments of the Nuphar alkaloids. The most significant findings of this study are: (i) axial methyl and thiomethylene groups are shielded more than their equatorial counterparts in all cases; (ii) axial and equatorial hydroxyl groups substituted at C-7 of deoxynupharidine and 7-epideoxynupharidine give α-, β-, and γ-effects in ring B similar to those in carbocyclic systems but also produce small upfield shifts in ring A especially at the carbons α to nitrogen; (iii) the effect of a 3-furyl group located at C-4 appears to have nearly the same effect on quinolizidine ring carbons as a methyl group in the same position, the effects being shielding and deshielding at the various ring carbons; (iv) N-oxide formation results in α-, β-, γ-, and δ-shielding and deshielding effects consistent with the incorporation of an axial oxygen into a trans-fused system or the formation of a cis-fused quinolizidine N-oxide; and (v) methylene or methyl groups attached to C-2 and C-4 of a thiolane, including that in the skeleton of the C30 thiaspirane alkaloids, experience deshielding δ-effects.

The synthesis of the nuclei of pyrrolizidine and indolizidine could be readily achieved by use of the one pot reaction named as “crisscross annulation”, which was extended to the synthesis of (±)-heliotridane ( 16 ) and (±)-nuphar indolizidine ( 20 ), a minor component of dried scent glands of the Canadian beaver.

The understory diatom species of Epithemia made up nearly 55% of the diet of the freshwater limpet Ferrissia fragilis, while these same diatom species made up

The network of internal gas spaces in the yellow waterlily constitutes a pressurized flowthrough system which forces oxygen to the rhizome buried in anaerobic sediment. This ventilation has been documented previously in a subspecies of Nuphar luteum with aerial leaves, and appeared to occur only during daylight when the leaves are warmed by the sun's radiation. In this study we have found the ventilation system operating in two different subspecies of N. luteum growing in Alaska and in Massachusetts. These plants have floating leaves so that during certain times of the year the leaves are warmed not only by the sun in daylight but also by lake water at night, allowing the ventilation to continue during darkness.

Mean total surface area available for epiphytic colonization during the study period was 1.032 m2 macrophyte surface per m2 of littoral zone for Phragmites, 0.810 m2 for Potamogeton, and 0.167 m2 for Nuphar. Seasonal rates of mean primary productivity of algal epiphytes on Phragmites from the surface to the light-compensation depth ranged from 84-1406 mg C m-2 littoral zone d-l; ranges for epiphytes on Potamogeton and Nuphar were 77-586 and 69-268 mg C m-2 littoral zone d-', respectively. Maximum rates were observed typically during June; minimum rates were observed typically during August to December. Mean daily productivity rates over the 12 month period were for epiphytes on Potamogeton 167.0, on Nuphar 100.4 and on Phragmites 671.2 mg C m-2 littoral zone d-1. Calculated annual production for epiphytes on Nuphar was 36.65, on Potamogeton 60.95 and on Phragmites 245.0 g C m-2 littoral zone yr-'. Epiphytic production data were typically considerably higher than production data obtained for littoral and pelagial planktonic algae and compare favorably with published data for epiphytic and periphytic production in Lawrence

A cyanide-insensitive superoxide dismutase (EC 1.15.1.1) was purified from leaves of the water lily Nuphar luteum (L.) Sibth. and Smith Subsp. macrophyllum (Small) Beal. The enzyme had a molecular weight of 46,000 and was composed of two equally sized subunits. Metal analysis showed the protein to contain about 1 gram atom of iron per dimer. The iron-containing superoxide dismutase was sensitive to H(2)O(2) as well as to azide. Antibody to the protein did not cross-react with iron superoxide dismutase isolated from the eucaryote Brassica or with algal extracts.

Relationships between the partitioning of Cu and Zn in lake sediments and their availability to the yellow water lily, Nuphar variegatum, were examined downstream from a major Cu/Zn mining and smelting complex in Northwestern Quebec, Canada. At each of 13 sampling sites, five N. variegatum individuals were collected, separated into stem and rhizome portions, and analyzed for total Cu and Zn. At the same sites, sediment cores were collected at the base of each plant; the 0- to 2-cm stratum was extruded, wet sieved (850 μm), and subjected to a sequential leaching procedure to determine the partitioning of Cu and Zn among various operationally defined geochemical fractions. Statistical analysis suggested that a significant portion of the Cu burden in N. variegatum was probably derived from the sediments, whereas the Zn content of the plant originated largely in the water column. The concentrations of Cu in the fractions most readily extracted from the sediment were the best indicators of Cu bioavailability in the sediment; normalization of these concentrations with respect to the Fe content of the sediment improved the relationship with [Curhizome], suggesting that Fe may play a protective role in regulating Cu bioavailability.

Home range areas of largemouth bass Micropterus salmoides floridanus in two central Florida lakes varied from 0.01 to 5.16 hectares, and maximum home range dimensions ranged from 50 to 2,364 m, based on 2,047 radio locations of 22 fish from August 1979 to May 1981. Greatest average daily movements occurred during June, May, and February; the smallest were in August. Several largemouth bass migrated during the spawning season as far as 3 km from their home ranges to wave-protected sites within canals. Largemouth bass were often located in small areas of their home range and occupied panic grasses Panicum spp., stands of cattails Typha sp., and spatterdock Nuphar luteum more often than other available vegetation types and open water. A segment of the largemouth bass population remained offshore: 36% of the tagged fish were at least 10 m from shore 25% of the time. Studies such as this should facilitate identification of habitat use by fish, projection of realistic harvest rates, and formulation of ...

The fragmentation pathways of ten 4-substituted quinolizid-2-ones were established using exact mass measurement, deuterium labelling and detection of metastable transitions. The base peak for most ketones was formed by cleavage of the C-2C-3 bond (α to the carbonyl group) and the benzylic C-4N bond. The decompositions examined were compared with those of the Nuphar alkaloids.

The aquatic environment is very sensitive to the pertubations which may accompany the mining of metals. Slight alterations in the loading of chemicals in freshwater systems are frequently reflected in large changes in the transfer of contaminants to aquatic species because of the potential for bioconcentration. Bioconcentration of radionuclides by the biota is a source of interest to both environmental scientists and regulatory agencies, since aquatic plants may be potential indicators for aquatic pollution and could also be significant sources of contaminants for herbivorous wildlife near mines and mine tailings systems. The discovery of a significant uranium orebody in a region encompassing many small lakes in the Okanagan region of south-central British Columbia permitted the assessment of seasonal uptake of naturally occuring radionuclides of the uranium series by aquatic plants. The objectives of this study were to assess the potential for bioconcentration of naturally occuring radionuclides in yellow pond-lily (Nuphar lute a subspecies polysepala (Engelmann) Beal),and to determine if seasonal variation in accumulation occured. MATERIALS AND METHODS