Developmental Control and Plasticity of Fruit and Seed Dimorphism in Aethionema arabicum.

Understanding how plants cope with changing habitats is a timely and important topic in plant research. Phenotypic plasticity describes the capability of a genotype to produce different phenotypes when exposed to different environmental conditions. In contrast, the constant production of a set of distinct phenotypes by one genotype mediates bet hedging, a strategy that reduces the temporal variance in fitness at the expense of a lowered arithmetic mean fitness. Both phenomena are thought to represent important adaptation strategies to unstable environments. However, little is known about the underlying mechanisms of these phenomena, partly due to the lack of suitable model systems. We used phylogenetic and comparative analyses of fruit and seed anatomy, biomechanics, physiology, and environmental responses to study fruit and seed heteromorphism, a typical morphological basis of a bet-hedging strategy of plants, in the annual Brassicaceae species Aethionema arabicum Our results indicate that heteromorphism evolved twice within the Aethionemeae, including once for the monophyletic annual Aethionema clade. The dimorphism of Ae. arabicum is associated with several anatomic, biomechanical, gene expression, and physiological differences between the fruit and seed morphs. However, fruit ratios and numbers change in response to different environmental conditions. Therefore, the life-history strategy of Ae. arabicum appears to be a blend of bet hedging and plasticity. Together with the available genomic resources, our results pave the way to use this species in future studies intended to unravel the molecular control of heteromorphism and plasticity.

Removal of Ni(II) and Cu(II) ions using native and acid treated Ni-hyperaccumulator plant Alyssum discolor from Turkish serpentine soil.

Alyssum discolor biomass was collected from serpentine soil and was used for removal of metal ions. The plant species grown on serpentine soils are known to be rich with metals ions and thus have more capability for accumulating heavy metals. Native and acid-treated biomass of A. discolor (A. discolor) were utilized for the removal of Ni(II) and Cu(II) ions from aqueous solutions. The effects of contact time, initial concentration, and pH on the biosorption of Ni(II) and Cu(II) ions were investigated. Biosorption equilibrium was established in about 60 min. The surface properties of the biomass preparations were varied with pH, and the maximum amounts of Ni(II) and Cu(II) ions on both A. discolor biomass preparations were adsorbed at pH 5.0. The maximum biosorption capacities of the native, and acid-treated biomass preparations for Ni(II) were 13.1 and 34.7 mgg(-1) and for Cu(II) 6.15 and 17.8 mgg(-1) dry biomass, respectively. The biosorption of Ni(II) and Cu(II) ions from single and binary component systems can be successfully described by Langmuir and Freundlich isotherms. When the heavy metal ions were in competition, the amounts of biosorbed metal ions on the acid treated plant biomass were found to be 0.542 mmolg(-1) for Ni(II) and 0.162 mmolg(-1) for Cu(II), the A. discolor biomass was significantly selective for Ni(II) ions. The information gained from these studies was expected to indicate whether the native, and acid-treated forms can have the potential to be used for the removal and recovery of Ni(II) ions from wastewaters.

New HPLC-chemometric approaches to the analysis of isoflavones in Trifolium lucanicum Gasp.

New HPLC-chemometric approaches were proposed for the simultaneous chromatographic quantification of daidzein, genistein, formononetin, and biochanin A in the samples consisting of the aerial parts of Trifolium lucanicum Gasp. (Leguminosae). Partial least squares and principal component regression algorithms were applied to the multiple chromatographic data set obtained by measuring at 240, 248, 256, and 264 nm to construct HPLC-partial least squares and HPLC-principal component regression calibrations. Chromatographic separation was carried out by using a mobile phase containing methanol, acetate buffer (pH=4.75) and acetonitrile (21:58:21, v/v/v) on the reversed phase column, Supelcosil™ LC-18 (15 cm×4.6 mm id). In addition, conventional HPLC based on the detection at a single wavelength was used for the determination of each compound in the extracts of T. lucanicum. The validity and applicability of the proposed HPLC-chemometric and conventional HPLC methods were performed by analyzing various synthetic plant samples. A good agreement was observed in the application of the proposed HPLC-chemometric tools to the synthetic and extracted samples of T. lucanicum.

Characterization of Szovitsia callicarpa volatile constituents obtained by micro- and hydrodistillation.

The volatile constituents of Szovitsia callicarpa Fisch. & C. A. Mey. were obtained from the fruits by microdistillation, due to the limited plant material availability. Initial GC-MS analyses of the obtained material showed an unidentified major constituent with a molecular ion peak at M+ 280. After hydrodistillation of the plant material, the resulting essential oil was also analyzed by GC and GC-MS, simultaneously. In total, twenty-two compounds, representing 98.6% of the microdistilled sample, were identified, whereas seventeen components were detected in the hydrodistilled oil, representing 98.5% of the total. The GC-MS analyses showed that the samples contained an unidentified major constituent, which was further purified from the hydrodistilled essential oil by micro-column chromatography. The structure was elucidated as alpha-kessyl acetate using 1H- and 13C-NMR spectroscopic and mass spectroscopic techniques. Other major constituents in the analytes were determined as longipinene, longicyclene and kessane. In addition, both samples, as well as the major compound alpha-kessyl acetate, were tested at 1 mg/mL concentration against the pathogen Candida tropicalis and for its free radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH*) by TLC-bioauthographic techniques. Both preliminary assays at the tested concentration showed no activity.