降香黄檀福建柏混交造林试验

在马尾松采伐迹地,进行了营造降香黄檀福建柏混交林、纯林试验,经过8年的经营管理,林木生长良好,调查可知,降香黄檀与福建柏混交造林生长的林分,比降香黄檀福建柏纯林生长的林分效果好。结果表明:降香黄檀福建柏混交林的林木生长量平均树高、胸径、枝下高、冠幅、单株材积、林木蓄积量,分别比降香黄檀、福建柏平均树高大8.76%、26.30%,胸径粗12.65%、29.85%,枝下高17.65%、61.29%,冠幅大7.22%、35.87%,单株材积大30.77%、112.50%,蓄积量大22.03%、94.50%。土壤肥力也提到了提高。     

广西鸟类分布新记录——褐翅燕鸥

2013年6月在广西涠洲岛自然保护区进行动物资源调查时,观察并拍摄到一群褐翅燕鸥,属广西鸟类新记录种。对该物种的分类、分布及种群状况进行了记述和讨论。     

Harnessing the Potential of Halogenated Natural Product Biosynthesis by Mangrove-Derived Actinomycetes

Mangrove-derived actinomycetes are promising sources of bioactive natural products. In this study, using homologous screening of the biosynthetic genes and anti-microorganism/tumor assaying, 163 strains of actinomycetes isolated from mangrove sediments were investigated for their potential to produce halogenated metabolites. The FADH₂-dependent halogenase genes, identified in PCR-screening, were clustered in distinct clades in the phylogenetic analysis. The coexistence of either polyketide synthase (PKS) or nonribosomal peptide synthetase (NRPS) as the backbone synthetases in the strains harboring the halogenase indicated that these strains had the potential to produce structurally diversified antibiotics. As a validation, a new enduracidin producer, Streptomyces atrovirens MGR140, was identified and confirmed by gene disruption and HPLC analysis. Moreover, a putative ansamycin biosynthesis gene cluster was detected in Streptomyces albogriseolus MGR072. Our results highlight that combined genome mining is an efficient technique to tap promising sources of halogenated natural products synthesized by mangrove-derived actinomycetes.     

Identification of Two Novel Anti-Fibrotic Benzopyran Compounds Produced by Engineered Strains Derived from Streptomyces xiamenensis M1-94P that Originated from Deep-Sea Sediments

The benzopyran compound obtained by cultivating a mangrove-derived strain, Streptomyces xiamenensis strain 318, shows multiple biological effects, including anti-fibrotic and anti-hypertrophic scar properties. To increase the diversity in the structures of the available benzopyrans, by means of biosynthesis, the strain was screened for spontaneous rifampicin resistance (Rif), and a mutated rpsL gene to confer streptomycin resistance (Str), was introduced into the S. xiamenensis strain M1-94P that originated from deep-sea sediments. Two new benzopyran derivatives, named xiamenmycin C (1) and D (2), were isolated from the crude extracts of a selected Str-Rif double mutant (M6) of M1-94P. The structures of 1 and 2 were identified by analyzing extensive spectroscopic data. Compounds 1 and 2 both inhibit the proliferation of human lung fibroblasts (WI26), and 1 exhibits better anti-fibrotic activity than xiamenmycin. Our study presents the novel bioactive compounds isolated from S. xiamenensis mutant strain M6 constructed by ribosome engineering, which could be a useful approach in the discovery of new anti-fibrotic compounds.     

土壤水分预测神经网络模型和时间序列模型比较研究

土壤水分运动是一个复杂的时间序列系统，其变化与区域气候条件和生态环境密切相关，具有明显的随机性波动。建立土壤水分动态变化模型可以使田间土壤水分的适时适量调节方便可行，有利于农田水利工程的规划和管理。该文利用人工神经网络方法和时间序列自回归(AR)模型进行了土壤水分预测建模研究，试验结果表明：在数据量较少的情况下，AR模型具有较好的预测效果；在数据量较多的情况下，神经网络模型能够获得较好的预测效果。     

黄淮杜泊羊线粒体DNA遗传多态性研究

线粒体DNA遗传变异丰富,是研究群体遗传多样性的重要手段。通过对黄淮杜泊羊、杜泊羊、鲁西黑头羊和小尾寒羊的线粒体D-loop遗传变异进行检测,分析4个品种的遗传多样性和品种间的遗传分化,构建系统发育树,并计算4个品种的遗传关系和遗传距离。结果表明,黄淮杜泊羊群体遗传多样性丰富（单倍型多样度h=0.984 21,核苷酸多样度P_i=0.015 50）,遗传稳定;系统发育树黄淮杜泊羊的黑头群体和白头群体聚为一类,与鲁西黑头羊、杜泊羊和小尾寒羊明显区分;黄淮杜泊羊与杜泊羊遗传距离最近（0.055）、与小尾寒羊遗传距离最远（0.070）,且黄淮杜泊羊与鲁西黑头羊、杜泊羊和小尾寒羊品种间遗传分化程度大。说明黄淮杜泊羊的遗传多样性丰富、遗传分化程度高,在遗传上明显区别于鲁西黑头羊、杜泊羊和小尾寒羊,黄淮杜泊羊黑头和白头群体的遗传一致,且群体遗传稳定,试验结果与育种设计方案相吻合,说明黄淮杜泊羊具备了新品种的遗传条件。     

基于正交试验设计的绿竹容器苗影响因素研究

采用L₉（3⁴）正交试验设计结合主成分分析法研究了影响绿竹容器苗质量的因素,试验设置的4个因素为容器类型、容器规格、基质种类和肥料类型,每个因素设置3个水平。试验结果表明：影响绿竹生长和发笋量的各因素主次顺序为：肥料类型>基质种类>容器规格>容器类型,其中肥料类型与基质种类为主导因子,对育苗质量起决定性作用;各因素的最优水平组合为：施用有机肥,采用泥炭与珍珠岩（7∶3）为基质,容器规格为25 cm×23 cm×23 cm（上口直径×下口直径×盆高）,容器采用无纺布容器。     

不同坡位对天然筇竹无性系种群生长的影响研究

研究了不同坡位（上坡位、中坡位、下坡位）的筇竹无性系种群的生长情况。结果表明：坡位不同对筇竹无性系种群生长的影响程度不同,随着坡位的增加,筇竹无性系分株的高度、枝下高、节长、胸径、分枝长、分枝角、叶长、叶宽、叶面积、鞭节长、鞭径、鞭芽数、活芽数、隔离者长度、隔离者节长、隔离者直径相应减少,隔离者总长度则相应增加。在水分和养分资源有效性不同的生境中,筇竹无性系表现出趋利避害的生态适应性对策。     

大气污染物排放清单空间分配优化探讨——以南京市为例

基于南京市2014～2016年大气污染物排放清单空间分配实践,梳理了影响大气污染物排放清单空间精准分配的因素,探讨了大气污染物排放清单空间分配优化途径及方法。针对空间分配方法优劣、分配原则匹配度、分配参数匹配及提取精准度、技术人员专业度均为影响大气污染物排放清单空间精准分配的重要影响因素,提出了提高空间分配分辨率、提高点源占比率、细化大气污染源分类分级、精确分配大气污染物排放量、优化空间分配参数等优化大气污染物排放清单空间分配的有效途径及办法。