Intra- and interspecific diversity in the response to waterlogging of two co-occurring white oak species (Quercus robur and Q. petraea)

Quercus robur L. and Quercus petraea (Matt.) Liebl. are sympatric oak species with different ecological requirements. Quercus robur is more tolerant to waterlogging than Q. petraea. This ecological divergence may play a role in the maintenance of the two species despite the absence of an insurmountable reproductive barrier between them. We predicted that the genetic architecture of traits related to waterlogging tolerance differs between the species. To gain insight into this architecture in the absence of genetic markers for waterlogging tolerance, we compared populations of seedlings of each species for diversity in the expression of quantitative phenotypic traits induced by severe hypoxia. To determine the capacity for hypertrophied lenticel formation, we applied gas-impermeable mastic to stems of seedlings. Two months after application, the mastic treatment had induced the formation of 3 (+/- 2) cm(-2) hypertrophied lenticels in the absence of root hypoxia. Leaf epinasty during root hypoxia was an early predictor of seedling mortality. Four weeks of waterlogging resulted in greater epinasty in Q. petraea than in Q. robur, but fewer hypertrophied lenticels (16 +/- 6 versus 21 +/- 9 cm(-2)) and adventitious roots (2.7 +/- 4.7 versus 5.2 +/- 5.9). Differences between species in these traits were associated with differences in the frequencies of extreme phenotypes rather than with a generally higher tolerance to waterlogging in Q. robur seedlings.     

Effects of water-saving irrigation on weed infestation and diversity in paddy fields in East China

The purpose of the article is to investigate the effects of water-saving irrigation on weed infestation and diversity in paddy fields; a two-year field experiment was conducted in Gaoyou Irrigation District, China. The responses of two irrigation treatments, controlled irrigation (CI) and traditional irrigation (TI), were observed and compared. The irrigation water use, yield, weed density, coverage ratio, height, species richness, density, dominant species, Shannon–Wiener index, and Pielou index were examined to analyze the water productivity, weed infestation, and diversity in paddy fields under the two treatments. The results showed that the water conditions were similar before the late tillering stage, and thereafter the CI fields were alternatively dry and wet with shallow standing water and low soil water content, while the TI fields were mostly continuously flooded by deep standing water and high soil water content. Irrigation water use for CI was 46.8% lower than TI. The CI treatment reduced weed density by 38.0%, decreased coverage ratio by 13.8%, and resulted in a 39.0% increase in weed height. Fewer species were found in CI fields than TI fields. The Shannon–Wiener index decreased by 11.5%, and the Pielou index increased by 3.2%. The changed water regime under CI not only impeded the growth of dominant species but also placed the whole weed community at a relatively stable level with reduced weed density. Meanwhile, aquatic weeds were well controlled; however, semi-aquatic weeds became the dominant species. In general, CI effectively reduced the risk of weed outbreaks, and weed diversity also decreased when it reduced irrigation water use.     

Showcasing the sovereignty of non‐self‐governing islands: New Caledonia

Since 1983, no non‐self‐governing island connected to a (neo‐) colonial European or American metropole has acquired full Westphalian sovereignty and these islands continue to operate within constitutional frameworks that connect them to these metropoles. Large majorities in referendums on several of these islands have rejected full sovereignty. This paper opens with a review of the essential elements of the concept of sovereignty in a historical and global context, before studying how sovereignty is unfolding in new forms in non‐self‐governing islands in the Pacific and the Caribbean. As a case study, an analysis is presented of how pro‐France (loyaliste) and pro‐independence (indépendantiste) parties in New Caledonia are negotiating sovereignty with France. Evidence is given of how these New Caledonian parties are creatively using classic Westphalian signifiers of sovereignty normally reserved for sovereign states such as flags, diplomatic representations and international treaties, while still negotiating New Caledonia's sovereignty with France. This suggests that in contrast to Westphalian sovereignty, a unique ‘Islandian’ concept of sovereignty is emerging. Islands that are not sovereign in a Westphalian sense can creatively disassemble and reassemble signifiers of Westphalian sovereignty to strengthen their continuous negotiations with their metropoles and their neighbours.     

Phenolic acid and flavonol water extracts of Delonix regia red flowers

Traditional healthy beverages in several African counties were home-made by water extraction of flowers of Delonix regia (Boj.) Raf. This tree belongs to the local biodiversity of plants used in the local medicine. It is also part of the traditional bioproducts marketed within African village communities. Scaling-up at pilot plant level, by mimicking this local recipe, lead to concentrated bioproducts containing various natural phenolic compounds, most of them have never been yet published. A three-steps process was used to prepare concentrated of water-extracted soluble phenolics. This process included: phenol extraction of dried plant by overnight diffusion in acidified water, clarification then concentration of the macerate, using membrane technology. Total phenol contents were determined as gallic acid equivalents using the Folin-Ciocalteu method. Total flavonoid contents, as delphinidin equivalents, were determined using the UV-vis colorimetric method. Comparison of concentration factors of both phenol families (phenolic acids and flavonols) contained in the 3 co-products obtained during the process were made between crude extracts, cross-flow microfiltration extracts and reverse osmosis concentrated extracts. Individual phenol compounds found in the products obtained were characterized and quantified by HPLC-DAD and by HPLC-MS². Among the 11 phenol compounds identified in the water-extracts, 3 have been already identified in the literature (2 phenolic acids and 1 flavonol), and 8 new compounds, in noticeable amounts, have never been cited. We have confirmed the presence of phenolic acids such as 3,4,5-trihydroxybenzoic (gallic acid), 3,4-dihydroxybenzoic (protocatechuic acid) and of quercetin. We have characterized for the first time the presence of 2-hydroxy 5-[(3,4,5 trihydroxyphenyl) carbonyl oxy] benzoic acid and of 7 other flavonols belonging to the quercetin, kaempferol and isorhamnetol compound families. Using both LCMS and NMR analyses, they have been identified and quantified as: rutin, quercetin 3-O-glucoside, quercetin 3-O-galactoside, quercetin trihexoside, quercetin 3-O-robinobioside, kaempferol rhamnosylhexoside and isorhamnetol rhamnosyl-hexoside.     

The Effect of Six Knotting Methods on the Biomechanical Properties of Three Large Diameter Absorbable Suture Materials

Objective— To evaluate the effect of 6 different knotting methods on the mechanical properties of 3 large absorbable suture materials used in large animal surgery. Study Design— In vitro mechanical study. Sample Population— Knotted suture loops (n=15 per group). Methods— Suture loops were created between two low‐friction pulleys with either 2 polydioxanone, 2 polyglactin 910 or 3 polyglactin 910. Strands were tied using 1 of 6 knotting technique: square knot, surgeon knot, clamped surgeon's knot, sliding half‐hitch knot (HH), Delimar knot and self‐locking knot (SLK). A single cycle to failure test was performed on each suture loop with a distraction rate of 100 mm/min. Failure modes were evaluated and breaking strength, elongation to failure and stiffness were compared. Results— All loops except two HH failed at the knot by acute breaking. The double‐stranded SLK was both stronger and stiffer than all other knots for each suture material. Clamping the first throw of the surgeon knot decreased load to failure significantly (143.11 ± 8.64 N) compared with not clamping (159.21 ± 6.14 N) for polydioxanone. Stiffness and elongation to failure were respectively lower and increased for 2 polydioxanone compared with both polyglactin 910 materials for all knotting techniques. Conclusions— Knotting techniques do influence structural properties of suture loops. The double strand loop conferred stiffer and stronger properties to the SLK Clinical Relevance— Clamping the first throw of polydioxanone should be avoided when tying a suture under tension even using large diameter suture materials. Using a SLK might be considered as a useful alternative when excessive tension is present.