Vivipary with precocious seedlings in mangrove plants was thought to be a hindrance to long-range dispersal. To examine the extent of seedling dispersal across oceans, we investigated the phylogeny and genetic structure among East Asiatic populations of Kandelia candel based on organelle DNAs. In total, three, 28 and seven haplotypes of the chloroplast DNA (cpDNA) atpB-rbcL spacer, cpDNA trnL-trnF spacer, and mitochondrial DNA (mtDNA) internal transcribed spacer (ITS) were identified, respectively, from 202 individuals. Three data sets suggested consistent phylogenies recovering two differentiated lineages corresponding to geographical regions, i.e. northern South-China-Sea + East-China-Sea region and southern South-China-Sea region (Sarawak). Phylogenetically, the Sarawak population was closely related to the Ranong population of western Peninsula Malaysia instead of other South-China-Sea populations, indicating its possible origin from the Indian Ocean Rim. No geographical subdivision was detected within the northern geographical region. An analysis of molecular variance (AMOVA) revealed low levels of genetic differentiation between and within mainland and island populations (phiCT = 0.015, phiSC = 0.037), indicating conspicuous long-distance seedling dispersal across oceans. Significant linkage disequilibrium excluded the possibility of recurrent homoplasious mutations as the major force causing phylogenetic discrepancy between mtDNA and the trnL-trnF spacer within the northern region. Instead, relative ages of alleles contributed to non-random chlorotype-mitotype associations and tree inconsistency. Widespread distribution and random associations (chi2 = 0.822, P = 0.189) of eight hypothetical ancestral cytotypes indicated the panmixis of populations of the northern geographical region as a whole. In contrast, rare and recently evolved alleles were restricted to marginal populations, revealing some preferential directional migration.

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The spin-reorientation transition (SRT) was observed when Ag overlayers deposited on Fe∕Pt(111) by magneto-optical Kerr effect measurements. The easy axis of the magnetization changes completely from the in-plane to out-of-plane direction after the coverage of Ag is 1 ML. The polar Kerr intensity and its coercivity as a function of Ag coverage are investigated during SRT. The easy axis of magnetization can be reversed back to the in-plane direction after the Ag overlayers are removed by sputtering. The chemical compositions of the interfaces are measured by Auger electron spectroscopy. The mechanism of SRT induced by Ag is discussed.

Structural and magnetic properties of a chemically ordered face-centered-cubic (111) Mn alloy filmMagneto-optical Kerr effect, low-energy electron diffraction, and Auger electron spectroscopy were used to investigate the magnetic properties and the growth mode of ultrathin Co films deposited on 1 ML ͑monolayer͒ Ni/ Pt͑111͒ at room temperature. No Kerr signal was observed when the thickness of Co film was below 3 ML, and the easy axis of the magnetization was in plane when the thickness of Co was greater than 3 ML at room temperature. The polar Kerr signal appeared after the sample was annealed at 450 K for 1 ML of Co. Further studies in the magnetic properties and surface composition of 3 ML Co/1 ML Ni/ Pt͑111͒ during an annealing process showed that the out-of-plane magnetization enhances significantly when Co and Ni atoms diffuse into the Pt substrate. The coercivity of the system can be adjusted by changing the annealing temperature. Measuring at room temperature, the coercivity increases when the annealing temperature rises. The possible mechanism of the evolution of magnetic properties with the structure of the interface is discussed.