Metabolism of [8-14]6-(benzylamino)purine by individual carnation flower components

Isolated stem, receptacle, ovary and petal tissues of the carnation flower (Dianthus caryophyllus L. cv. White Sim) all metabolized [8-¹⁴C]6-(benzylamino) purine. Ribosyl 6-(benzylamino)purine was the major metabolite formed in all flower components. The extent of metabolism and the ratios of the various metabolites of 6-(benzylamino)purine detected within each flower component varied. The receptacle, in particular, was distinct from other flower components with respect to the extent of 6-(benzylamino)purine metabolism.Abbreviations ADE adenine - ADO adenosine - BA 6-(Benzylamino)purine - [9R]BA ribosyl 6-(benzylamino)purine - [9R-MP]BA ribosyl 6-(benzylamino)purine-5-monophosphate - [7G]BA/[9G]BA 7/9--D-glucopyranosyl 6-(benzylamino)purine     

Floral morphogenesis of the Maddenia and Pygeum groups of Prunus (Rosaceae), with an emphasis on the perianth

Although the vast majority of Prunus L. (Rosaceae) species have clearly differentiated sepals and petals, two former genera Maddenia and Pygeum have been described as having an undifferentiated perianth. However, floral morphological and morphogenetic data are scarce, and a renewed investigation is essential to understand the evolution of the perianth differentiation. Here, floral morphogenesis in Prunus hypoleuca (Koehne) J.Wen (=Maddenia hypoleuca Koehne) and Prunus topengii (Merr.) J. Wen & L. Zhao (=Pygeum topengii Merr.) were examined with scanning electron microscopy. The floral development demonstrates that the ten perianth parts can be distinguished as five sepals in an external whorl and five petals in an internal whorl. The sepal primordia are broad, crescent-shaped, and truncate. The petal primordia are rounded and initially resemble the androecium. However, at maturity petals and sepals look much the same in the two species, differing from other Prunus species. The ovule is anatropous and unitegmic, but there is a basal appendage near the ovule of P. hypoleuca which is absent in P. topengii. The direction of development of floral nectaries in the hypanthium is basipetal in P. hypoleuca but acropetal in P. topengii. Perianth segments are differentiated in the two groups and the similarity of the perianth parts is secondarily acquired. Our results support the separation of the Maddenia and Pygeum groups as well as their inclusion in a broader monophyletic Prunus based on molecular phylogenetic studies. We herein provide a new nomenclatural change: Prunus topengii (Merr.) J. Wen & L. Zhao, comb. nov.     

Graphitic Carbon Nitride Induced Micro‐Electric Field for Dendrite‐Free Lithium Metal Anodes

Uncontrolled dendrites resulting from nonuniform lithium (Li) nucleation/growth and Li volume expansion during charging cause serious safety problems for Li anode‐based batteries. Here the coating of nickel foam with graphitic carbon nitride (g‐C₃N₄) to have a 3D current collector (g‐C₃N₄@Ni foam) for dendrite‐free Li metal anodes is reported. The lithiophilic g‐C₃N₄ coupled with the 3D framework is demonstrated to be highly effective for promoting the uniform deposition of Li and suppressing the formation of dendrites. Both density functional theory calculations and experimental studies indicate the formation of a micro‐electric field resulting from the tri‐s‐triazine units of g‐C₃N₄, which induces numerous Li nuclei during the initial nucleation stage, effectively guiding the following Li growth on the 3D Ni foam to be well distributed. Furthermore, the 3D porous framework is favorable for absorbing any volume change and stabilizing the solid–electrolyte interphase layer during repeated Li plating/stripping. As such, a Li metal anode based on the g‐C₃N₄@Ni foam has a remarkable electrochemical performance with a high Coulombic efficiency (98% retention after 300 cycles), an ultralong lifespan up to 900 h, as well as a low overpotential (<15 mV at 1.0 mA cm^?2) at a Li deposition of 9.0 mA h cm^?2.     

A novel algorithm to accelerate the convergence of grand canonical Monte Carlo simulation of non-uniform fluids

A novel Monte Carlo scheme, MTZ-GCMC, utilising the ‘mass transfer zone’ (MTZ) between the fluid phase and the adsorbed phase, is proposed as an effective method for simulating the approach of a non-uniform fluid to equilibrium. We have applied this procedure to study the adsorption of gases in a closed-end graphitic slit pore, paying special attention to the region where there is a very sharp (but not vertical) condensation transition within the pore. In this region, conventional Monte Carlo (MC) requires a much greater computational effort to achieve convergence and may lead to incorrect results. In the MTZ-GCMC scheme, the insertion/deletion trials during the course of a simulation are restricted to the MTZ, which is identified and characterised by the percentage of successful insertions (PSI). Since the MTZ changes during the equilibration stage, the PSI must be updated on the fly until equilibrium has been reached. The distinct advantage of this scheme is that unnecessary insertion and deletion trials in the dense adsorbed phase, and the gas-like region are avoided; since most of these trials would be rejected, this means that convergence to the true equilibrium can be achieved an order of magnitude faster.     

Comparative floral development in Lardizabalaceae (Ranunculales)

Lardizabalaceae, one of seven families of Ranunculales, represent a monophyletic group. The family has functionally unisexual flowers with the organs in trimerous whorls, petaloid sepals and sometimes nectariferous petals. Among Ranunculales, Lardizabalaceae share several floral characters and climbing habit with Menispermaceae, but molecular analyses indicate that Circaeasteraceae and Lardizabalaceae form a strongly supported clade. Morphological and ontogenetic studies of flowers have proved to be a good complement to molecular data in clarifying relationships. Floral organogenesis has been studied in very few species of the family. This study investigates the comparative floral development of three species from three genera (Decaisnea, Akebia and Holboellia) of Lardizabalaceae using scanning electron microscopy. Flowers have a whorled phyllotaxis. Within each whorl, the organs are initiated either simultaneously or in a rapid spiral sequence. In Akebia, six sepals are initiated, but one to three sepals of the second whorl do not further develop. The presence of three sepals in Akebia is thus a developmentally secondary simplification. The petals (if present) are retarded in early developmental stages; stamens and petals are different in shape from the beginning of development. The retarded petals may not be derived from staminodes in Lardizabalaceae. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 166 , 171–184.     

The inrolling phenomena of petals during senescence in cut carnations (Dianthus caryophyllus L cv. shinkibo)

The inward rolling of the petals is one of typical symptoms observed in the process of climacteric corolla senescence. Inrolling was mimicked by treating the lower part of the petal instead of the whole petal of cut carnations (cv. Shinkibo) with exogenous ethylene. In these petal segments, the climacteric ethylene burst occurred right at the inrolling stage, indicating that these petal segments may be an excellent model system for examining corolla senescence. According to kinetic analysis, an asymmetry in the lengths of the adaxial and abaxial sides of petal segments appeared to be the direct cause of the inward rolling. While the length of the abaxial side of the transverse section of petal segments increased during the analysis, the ultimate length of the adaxial side was shrunken by the same ethylene action. Interestingly, the kinetics curve of the adaxial side consisted of two distinct phases. The rate of expansion/shrink of either side of the petal and the slope of each phase varied with the chemicals affected in the rolling process of the petal segments: e.g., n-octanoic acid, polyamines, and inhibitors of the Ca²⁺-channel blocker.     

Location and biosynthesis of monoterpenyl fatty acyl esters in rose petals

The upper epidermal layer of cells and the epicuticular wax surface of Lady Seton rose petals are sites of biosynthesis and accumulation, respectively, of a family of terpenyl fatty acyl esters. These esters are based mainly on the acyclic monoterpene alcohol geraniol coupled primarily to fatty acids of chain lengths 16-20 and in mass terms represent from 14% to 64% of the total monoterpenes present in the petals. The lipophilic nature of these non-volatile esters of the monoterpene alcohols contrasts with that of the lipophilic volatile parent alcohols themselves and with the hydrophilic, non-volatile, glucoside derivative of the other principal petal fragrant compounds, the phenylpropanoids, beta-phenyl ethanol and benzyl alcohol. These latter compounds are also synthesised and are resident in the petal. Biosynthetic studies confirmed that the petal upper epidermal cell layer has the capacity to incorporate mevalonic acid into the monoterpene component of the fatty acyl ester. The biosynthesis of the monoterpene component of the fatty acyl ester occurs via the mevalonic acid pathway in Lady Seton as well as in the hybrid tea rose Fragrant Cloud. In the latter flower the biosynthesis of geraniol was biosynthetically trans as was the formation of nerol and citronellol. Both geraniol and nerol were shown to be precursors of citronellol via an NADPH dependent reductase reaction. Oleic acid is assimilated into the acyl moiety of the terpenyl ester in Lady Seton isolated petal discs. It is probable that the lipophilic non-volatile terpenyl fatty acyl esters represent a stable storage form of the corresponding alcohols from their residency within the epicuticular wax layer. These acyl esters may realise, on hydrolysis, additional aroma notes from the living flower and potentially commercially significant quantities of the fragrant terpenols during oil of rose essence production.     

Evidence for the involvement of gibberellins in developmental phenomena associated with carnation flower senescence

The application of 10^–4 M GA₃ to preclimacteric carnation flowers delayed senescence, climateric ethylene production reduced the rate of loss in fresh weight of intact flowers and the decrease in moisture content of the petals. The loss in flower fresh weight commenced prior to the ethylene climacteric. The increased membrane permeability which was observed when intact, control flowers were half opened, was delayed by GA₃ application. This effect was only significant when GA₃ was applied to young flowers. In addition to slowing down the loss in fresh mass, GA₃ inhibited ethylene production by the style and stigma. The increase in ovary dry weight and chlorophyll content and the associated decrease in petal dry weight was slowed down by GA₃ but not arrested, this despite reduced ethylene production by the ovary. It is proposed that a decline in endogenous gibberellin may be a correlative event associated with the onset of the senescence process in carnation flowers.Abbreviations GA₃ gibberellic acid - STS silver thiosulphate     

Direct coupled column separation and determination of the diastereomeric glucuronides of almokalant, a new class III antiarrhythmic drug, in human urine.

A reversed-phase coupled column separation (CCS) system for the analysis of two diastereomeric glucuronides of almokalant, a new class III antiarrhythmic drug, in human urine is described. After direct injection of urine samples (50 microliters) the glucuronides were isolated by complex formation on a terbium(III) loaded strong cation exchanger at alkaline pH. The solutes were eluted from the precolumn by an acidic mobile phase, enriched and separated on Hypercarb (porous graphitic carbon) as analytical column with 0.1 M acetic acid pH 2.8 and 30% acetonitrile as mobile phase. The calibration graph was linear (r2 = 0.9999) and the detection limits were in the low picomole (UV) or femtomole (fluorescence) range. Optimization of the analytical column revealed that elution order and selectivity for the glucuronides were dependent on the buffer agent and temperature used. By appropriate choice of mobile phase conditions all four diastereomers could be separated.     

Visits to Manipulated Flowers by Episyrphus balteatus (Diptera: Syrphidae): Partitioning the Signals of Petals and Anthers

In a number of previous studies attention has been directed to the selection on corolla dimensions by pollinator preference, but anthers may also be a signal. This experiment examined the relative importance of petals and anthers in the attraction of male Episyrphus balteatus (Diptera, Syrphidae) to individual oil-seed rape flowers (Bracus rapae oleifera). Rape flowers have four petals and six anthers. Nine treatments were created, of flowers with four, two, or zero petals and six, three, or zero anthers. Twenty males were tested for preference among the experimental flowers by recording the sequence and duration of their visits (which were all for feeding) to the flowers. The number of first visits and the duration of visits on each flower were significantly related to the number of anthers but not the number of petals. There was no correlation between petal area and pollen load of control flowers. It is suggested that Syrphidae may not always attend to petals, and variation in preference of different pollinator taxa should be taken into account when discussing the evolution of floral characters.