Demonstration of an 8-Gbit/s quadrature-phase-shift-keying coherent underwater wireless optical communication link using coherent heterodyne detection under scattering conditions.

In this paper, we experimentally demonstrate an 8-Gbit/s quadrature-phase-shift-keying (QPSK) coherent underwater wireless optical communication (UWOC) link under scattering conditions at 532 nm. At the transmitter, we generate the 532-nm QPSK signal using second-harmonic generation (SHG), where the 1064-nm signal modulated with four phase levels of an 8-phase-shift-keying (8-PSK) format is phase doubled to produce the 532-nm QPSK signal. To enhance the receiver sensitivity, we utilize a local oscillator (LO) at the receiver from an independent laser source. The received QPSK data beam is mixed with the independent LO for coherent heterodyne detection. Results show that the bit error rates (BERs) of the received QPSK signal can reach below the 7% forward error correction (FEC) limit under turbid water with attenuation lengths (γL) up to 7.4 and 6.1 for 2- and 8-Gbit/s QPSK, respectively. The corresponding receiver sensitivities are -34.0 and -28.4 dBm for 2- and 8-Gbit/s QPSK, respectively.

The complete chloroplast genome sequence of Melliodendron xylocarpum (Styracaceae).

Melliodendron xylocarpum Handel-Mazzetti is a rare tree, distinct member of the family Styracaceae. In this study, we determined the complete chloroplast (cp) genome sequence of M. xylocarpum in an effort to provide genomic resources useful for promoting its conservation. The entire cp genome was determined to be 157,165 bp in length. It contains the typical structure and gene content of angiosperm plastome, The plastome contains a large single-copy (LSC) and a small single-copy (SSC) regions of 90,193 and 18,486 bp, respectively, which were separated by a pair of 24,243 bp inverted repeat (IR) regions. The genome contained 130 genes, including 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The GC content of M. xylocarpum genome is 37.21%. The complete plastome sequence of M. xylocarpum will provide a useful resource for the conservation genetics of this species as well as for the phylogenetic studies for Styracaceae. Phylogenetic analysis revealed that M. xylocarpum is closely related to Changiostyrax dolichocarpus H.S.Lo & D.Fang, but forms an independent evolutionary branch.

The complete chloroplast genome sequence of Styrax odoratissimus (Styracaceae).

Styrax odoratissimus Champ. ex Benth., also known as the extraordinary aromatic plant of Styracaceae, has been seriously threatened due to human activities. In this study, the complete chloroplast (cp) genome sequence of S. odoratissimus was determined by applying next-generation sequencing. The entire cp genome was determined to be 157,921 bp in length. It contained large single-copy (LSC) and small single-copy (SSC) regions of 87,524 bp and 18,301 bp, respectively, which were separated by a pair of 26,048 bp inverted repeat (IR) regions. The genome contained 130 genes, including 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The overall GC content of S. odoratissimus genome is 36.96% and the corresponding values in LSC, SSC, and IR regions are 34.80, 30.27, and 42.92%, respectively. A phylogenetic tree reconstructed by 31 chloroplast genomes reveals that S. odoratissimus is most related to Styrax grandiflorus Griffith.

The complete chloroplast genome sequence of Melliodendron wangianum (Styracaceae).

Melliodendron wangianum Hu (Styracaceae) is a rare endemic tree of Styracaceae in China. In this work, we set forth the complete chloroplast (cp) genome sequence of M. wangianum using next-generation sequencing. The entire cp genome was determined to be 157,196 bp in length. It contained large single-copy (LSC) and small single-copy (SSC) regions of 90,210 bp and 18,4561 bp, respectively, which were separated by a pair of 24,265 bp inverted repeat (IR) regions. The genome contained 128 genes, including 83 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The overall GC content of the genome is 37.19%. Phylogenetic analysis confirmed the traditional family-level Taxonomy of Melliodendron, indicating that M. wangianum is closely related to a sister species to M. xylocarpum in Styracaceae.

The complete chloroplast genome of Styrax faberi Perk. (Styracaceae).

Styrax faberi Perk., a native plant belonging to Styracaceae mainly distributed in the region south of the Yantze River, China, is both a medicinal and landscape plant. Here we studied the complete chloroplast (cp) genome sequence of S. faberi by using next-generation sequencing. The whole complete cp genome of S. faberi totals 159,424 bp in length, containing a large single-copy (LSC) region of 85,845 bp, and a small single-copy (SSC) region of 18,027 bp 133 genes, including 8 rRNA genes, 37 tRNAs genes, and 88 protein-coding genes constituted the genome. The GC content of S. faberi is 36.92%. The phylogenetic analysis reveals that S. faberi is a sister species to Styrax odoratissimus and Styrax zhejiangensis in Styracaceae.