Genetic relationship between offspring and guardian adults of a rhacophorid frog and its care effort in response to paternal share

The rhacophorid frog, Kurixalus eiffingeri, is one of only a few frog species that exhibits polyandry and paternal care of eggs. Previous studies predicted that multiple paternity within an egg clutch could influence the degree of paternal care and reproductive strategies. We used microsatellite DNA markers to assess the prevalence of multiple paternity within egg clutches and the relationship between male paternal care and the percent of male’s genetic contribution to the clutch, i.e., paternal share. We conducted field observations of paternal care and collected tissues from both male frogs and tadpoles for parentage analyses. Our results showed that at least five out of 31 egg clutches had multiple paternity. Attending males were always the genetic fathers of some, if not all of the eggs in the clutch they guarded. All egg clutches except one were attended by one male frog but the attending male did not necessarily sire the majority of offspring. Multiple paternity in all cases consisted of two fathers and one mother and most likely resulted from synchronous polyandry. Paternal care effort correlated significantly with the male’s genetic contribution to the clutch, suggesting that male frogs adjust the effort expended in care in response to paternal share. In addition, our results suggest that externally fertilizing species with parental care and multiple paternity may develop novel reproductive and behavioral strategies to safeguard their parental investment and overcome sperm competition.     

Trap barricading and decorating by a well-armored sit-and-wait predator: extra protection or prey attraction?

Animals may build multiple structures to provide benefits to counter the costs of building. Many orb web spiders add multiple structures, e.g., barricading barrier webs and silk decorations, to their webs and these structures have been hypothesized to function to deter predators or attract prey. The heavily armored spiny spiders construct barrier webs around their orb webs and decorate them with conspicuous silk tufts. Why these organisms, already well protected by a thick cuticle and spines, make the extra investment of building barrier webs and adding conspicuous silk decorations is not known. We predicted that these structures function to both attract prey and deter predators. Field experiments were conducted in two consecutive years using orb webs built by the East Asian spiny spider Thelacantha brevispina. We either (1) concealed the decoration, (2) removed the barrier webs, or (3) left the decorations and barrier webs intact. We found year and treatment to interactively influence prey interception rates. In 2010, but not in 2009, we found prey interception with T. brevispina webs to be greater when the decorations were conspicuous than when they were concealed suggesting that the decorations may lure prey. Prey interception was lower when the barrier webs were present without decorations compared to when they were absent without decorations. The prey-attracting function of the decorations thus may counter the reduction in prey interception incurred by adding a barrier web. Predatory wasp interactions were not influenced by any of our treatments, probably because the spiders’ thick cuticle is the primary means of protection from wasps. Bird predation events, while rare, occurred only when decorations were concealed or the barrier webs were removed. It is therefore plausible that the tuft decorations both lure prey and deter birds.     

北京建成区道路绿化空间结构和行道树健康状况

采用实地普查测量方法,定量研究了北京建成区188条道路行道树的树种结构、径级分布、立木层次和健康状况。结果表明,国槐（Sophora japonica）、毛白杨（Populus alba）、银杏（Ginkgo biloba）是建成区主要行道树种,使用量分别占研究区树木总株数的54．7％、13．7％和7．4％。建成区树木...     

贵州浓香型白酒大曲中霉菌的18S rDNA系统发育分析

从贵州某名酒厂大曲中分离到104株丝状真菌(霉菌),通过形态特征和生理特性检测等传统鉴定方法,初步把形态和生理生化特征一致的霉菌归类为14个大类群;并采用18S rDNA序列分析,进一步把菌株归类为MJ-I至MJ-V五个类群,随后构建系统发育树.结果表明,样品中的霉菌以曲霉属(Aspergillus)为主,占总分离菌数...     

2008年初特大冰雪灾害对粤北地区杉木（Cunninghamia lanceolata）人工林土壤理化性质的影响

2008年8月,选择具有代表性的样地（受冰雪灾害较轻、受到冰雪灾害影响、受到冰雪灾害后皆伐清理样地）,用野外调查和室内分析相结合的方法,对广东省天井山林场杉木人工林土壤理化性质进行分析。结果表明：（1）粤北地区杉木人工林在受到冰雪灾害后,0-60 cm的土壤容重比未受到损害的上升8.1%-16.4%,孔隙度下降8.9%-11.9%,自然含水量减少17.1%-28.6%,皆伐清理后,土壤容重比未受到损害的下降1.5%~9.5%;孔隙度上升1.2%~5.9%,自然含水量增加44.2%~68.1%。（2）受损后,土壤pH值未发生变化,浅层（0-40 cm）有机质质量分数比未损样地下降（1.3%-9.4%）,深层（〉40 cm）有机质质量分数提高30.5%;各层土壤全氮、全磷、有效氮、有效磷和有效钾质量分数分别下降13.4%、30.3%、16.7%、37.6%和37.2%,全钾质量分数上升21.0%,且与未损样地的差异显著;土壤交换性钙和交换性镁大幅减少,分别为28.1%和43.4%。进行皆伐清理后,有机质质量分数比未损样地提高207.9%,土壤全氮、全钾、有效氮和有效磷质量分数升高138.7%、10.2%、161.3%和540.0%,全磷、有效钾、交换性钙和交换性镁的质量分数下降2.6%、9.0%、28.7%和24.3%,各土层变化不一致。（3）冰雪灾害的发生使杉木人工林林下土壤紧实度增加,不利于土壤呼吸、空气传导和土壤养分的累积;而经过清理后,土壤变得较为疏松,通透性增强,含水量增加,有利于土壤团粒结构的增强、土壤微生物活动和土壤养分的累积及转化。因此,冰雪灾害后对受损林地进行及时的清理对植被恢复重建尤为重要。     

环介导等温扩增技术(LAMP)检测人星状病毒方法的建立及其在再生水检测中的应用

为快速高效地检测人星状病毒,建立了一种新的试验方法——环介导等温扩增技术(loop-mediated isothermal amplification technology,LAMP),并对人星状病毒LAMP反应条件进行了优化.结果表明,镁离子终浓度为4 mmol·L-1、甜菜碱终浓度为1mol.L-1的25μL体系下...     

Characteristics of CO2 release from forest soil in the mountains near Beijing

CO₂ release from forest soil is a key driver of carbon cycling between the soil and atmosphere ecosystem. The rate of CO₂ released from soil was measured in three forest stands (in the mountainous region near Beijing, China) by the alkaline absorption method from 2004 to 2006. The rate of CO₂ released did not differ among the three stands. The CO₂ release rate ranged from ??341 to 1,193 mg m^???2 h^???1, and the mean value over all three forests and sampling times was 286 mg m^???2 h^???1. CO₂ release was positively correlated with soil water content and the soil temperature. Diurnally, CO₂ release was higher in the day than at night. Seasonally, CO₂ release was highest in early autumn and lowest in winter; in winter, negative values of CO₂ release suggested that CO₂ was absorbed by soil.     

好氧反硝化菌种DF2的分离鉴定及生理生化特性分析

分离了新型的高效反硝化细菌并研究其生物脱氮效率。通过观察形态学、生理生化鉴定和16SrRNA基因同源分析来鉴定菌种,致力于研究微生物污水脱氮处理的实际效果和克服反硝化过程中有害中间产物的积累。利用BTB培养基从水平潜流人工湿地基质中初步筛选出了9株平板阳性菌,革兰阴阳性均有。经试验研究发现该9种菌株在好氧条件下均具有一定的脱氮能力,其中以DF2和DF3 2种菌株脱氮能力最为显著,在3 d时间内NOX--N去除率达到了95%以上,NO2--N仅有微量积累;而其它7种菌株对NO3--N的去除率可以达到98%以上,但是NO2--N积累比较严重,积累量达到了NO3--N去除的50%~70%左右。经测序分析鉴定DF2和DF3分别属于德克斯氏菌属（Derxia）和假单胞菌属（Pseudomonadaceae）。德克斯氏菌属作为除氮的反硝化菌属在以往的研究中鲜有报道,该菌在好氧条件下可以合成周质NAR的亚基基因（napA）。     

Degradation of dye rhodamine B under visible irradiation with Prussian blue as a photo-Fenton reagent

Rhodamine B can be degraded using Prussian blue as a photo-Fenton like reagent under λ > 420 nm visible irradiation. Kinetic studies show ln(C _o/C _t ) is linearly proportional to the reaction time during the photo-degradation process; thus, the degradation reaction obeys a pseudo-first order kinetic law. It is very interesting that the presence of salinity such as 0.1 M KCl can speed up greatly the degradation rate: the time to achieve 90.0% degradation ratio is shortened from 120.0 to 40.0 min under comparable conditions, which is very useful in the treatment of wastewaters with high content of salinity.     

免耕对华北平原潮土N2O和CO2排放的影响

采用静态箱-气相色谱法研究了免耕和常规耕作下玉米生长季华北平原潮土N2O和CO2的排放特征.结果表明,免耕土壤N2O累积排放量(以N2O-N计,下同)为0.31 kg· hm-2,略高于常规耕作土壤的0.27 kg·hm-2,两者没有显著差异.灌水、强烈降水或连续阴天会诱发土壤大量排放N2O,免耕处理N2O排放峰值(28.1 ～38.4μg·m-2·h-1)高于常规耕作处理(18.6 ～25.7 μg·m-2·h-1).免耕处理CO2累积排放量(以CO2-C计,下同)为1 880 kg·hm-2,显著高于常规耕作土壤的1 333 kg·hm-2.土壤N2O和CO2排放通量与土壤温度呈显著指数相关,常规耕作处理下的相关程度更高.