Raman spectra of single-wall carbon nanotubes ͑SWCNTs͒ were measured at different temperatures by varying the incident laser power. The elevated temperature of the SWCNTs and multiwall carbon nanotubes ͑MWCNTs͒ is confirmed to be due to the presence of impurities, defects, and disorder. The temperature coefficient of the frequency of the CC stretching mode E 2g ͑GM͒ and that of the radial breathing mode in the SWCNT were determined to be ϳϪ0.038 and ϳϪ0.013 cm Ϫ1 /K, respectively. It is found that the temperature coefficient of the GM in the SWCNT is larger than that of the MWCNT, highly oriented pyrolytic graphite, and the graphite. This is attributed to the structural characteristic of the SWCNT-a single tubular carbon sheet with smaller diameter.

Summary1. Soil micro-organisms play important roles in ecosystems and respond quickly to environmental changes. We examined how understory removal and tree girdling influence the composition of soil microbial community and the litter decomposition in two subtropical plantations. 2. Phospholipid fatty acids (PLFAs) analysis was used to characterize soil microbial community. Redundancy analysis and principal response curves (PRC) were used to investigate the relationships between soil microbial community and environmental factors. 3. Understory removal significantly reduced the amount of fungal PLFAs, the ratio of fungal to bacterial PLFAs, and the litter decomposition but did not affect bacterial PLFAs and total PLFAs. In contrast, tree girdling did not affect the soil microbial characteristics. The changes in soil microbial community caused by understory removal were mainly attributed to the indirect effects such as increased soil temperature and soil NO 3 ) -N availability. In addition, PRC analysis showed that the relative abundance of most PLFAs increased in response to understory removal in the 2-year-old plantation but decreased in the 24-year-old plantation. 4. We propose that understory plants are important components in subtropical forest ecosystems, and play different roles in maintaining soil microbial community and driving litter decomposition processes in young vs. old plantations. The functions of understory plants should be considered in forest management and restoration. The negligible effect of tree girdling on the soil micro-organisms can be attributed to the resprouting trait and mycorrhizal interactions of Eucalyptus.

Coconut palm (Cocos nucifera,2n = 32), a member of genus Cocos and family Arecaceae (Palmaceae), is an important tropical fruit and oil crop. Currently, coconut palm is cultivated in 93 countries, including Central and South America, East and West Africa, Southeast Asia and the Pacific Islands, with a total growth area of more than 12 million hectares [1]. Coconut palm is generally classified into 2 main categories: “Tall” (flowering 8–10 years after planting) and “Dwarf” (flowering 4–6 years after planting), based on morphological characteristics and breeding habits. This Palmae species has a long growth period before reproductive years, which hinders conventional breeding progress. In spite of initial successes, improvements made by conventional breeding have been very slow. In the present study, we obtained de novo sequences of the Cocos nucifera genome: a major genomic resource that could be used to facilitate molecular breeding in Cocos nucifera and accelerate the breeding process in this important crop. A total of 419.67 gigabases (Gb) of raw reads were generated by the Illumina HiSeq 2000 platform using a series of paired-end and mate-pair libraries, covering the predicted Cocos nucifera genome length (2.42 Gb, variety “Hainan Tall”) to an estimated ×173.32 read depth. A total scaffold length of 2.20 Gb was generated (N50 = 418 Kb), representing 90.91% of the genome. The coconut genome was predicted to harbor 28 039 protein-coding genes, which is less than in Phoenix dactylifera (PDK30: 28 889), Phoenix dactylifera (DPV01: 41 660), and Elaeis guineensis (EG5: 34 802). BUSCO evaluation demonstrated that the obtained scaffold sequences covered 90.8% of the coconut genome and that the genome annotation was 74.1% complete. Genome annotation results revealed that 72.75% of the coconut genome consisted of transposable elements, of which long-terminal repeat retrotransposons elements (LTRs) accounted for the largest proportion (92.23%). Comparative analysis of the antiporter gene family and ion channel gene families between C. nucifera and Arabidopsis thaliana indicated that significant gene expansion may have occurred in the coconut involving Na+/H+ antiporter, carnitine/acylcarnitine translocase, potassium-dependent sodium-calcium exchanger, and potassium channel genes. Despite its agronomic importance, C. nucifera is still under-studied. In this report, we present a draft genome of C. nucifera and provide genomic information that will facilitate future functional genomics and molecular-assisted breeding in this crop species.

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