细鳞鱼的生物学特性及其在华北分布范围的变化

本文报导了细鳞鱼(Braochymystax lenokP.)的形态构造、食性及其生态环境。调查了华北地区细鳞鱼分布变化情况,并阐明由于生态环境等因素的变化是引起该种在华北地区分布范围缩小的原因,同时提出保护细鳞鱼资资源的措施。     

渔业数据失真对两种非平衡剩余产量模型评估结果的影响比较

为了研究渔业数据失真对两种非平衡剩余产量模型评估结果的影响,以南大西洋长鳍金枪鱼渔业产量和单位捕捞努力量渔获量(CPUE)数据作为基础数据,加入5种不同程度[变异系数(CV)=1%、5%、10%、20%和30%]的随机误差,模拟了(1)无数据失真,(2)仅产量数据失真,(3)仅CPUE数据失真,(4)产量和CPUE数据均失真等4种情况。利用基于ASPIC的非平衡剩余产量模型(ASM)和基于贝叶斯状态空间建模方法的非平衡剩余产量模型(BSM)分别评估了最大可持续产量(MSY)、B_(MSY)、F_(MSY)、B_(2011)/B_(MSY)、F2011/F_(MSY)等5种生物学参考点和管理指标。结果显示,在无数据失真情况下,ASM和BSM评估的MSY分别为2.866×10~4 t和2.836×10~4 t,B_(2011)/B_(MSY)分别为1.366和1.324,F2011/F_(MSY)分别为0.627和0.667,均相差不大,表明该渔业目前状态良好,ASM得到了较大的B_(MSY)(31.48×10~4 t)和较小的F_(MSY)(0.091);数据失真对ASM评估的B_(MSY)和F_(MSY)分别产生了严重的过低估计和过高估计,且CPUE数据失真产生的影响要比产量数据失真大;随着随机误差的增大,BSM评估的生物学参考点和管理指标的绝对百分比偏差有增大趋势;与ASM相比,BSM能够更好地处理渔业数据中存在的随机误差,除了MSY以外,BSM评估的生物学参考点和管理指标绝对百分比偏差均要比ASM的评估结果低,尤其是B_(MSY)和F_(MSY)。因此,在使用存在较大随机误差的渔业数据进行资源评估时,BSM具有一定的优势。     

植物诱导抗病技术的发展现状

对植物诱导抗病技术进行了综述;针对生物诱导因子、物理诱导因子和化学诱导因子,分析了各种诱导因子的特征和应用;指出了植物诱导抗病性研究的现状和问题;并对诱导抗病性的应用和发展方向做作了概括.     

细足捷蚁入侵云南河口植胶区初报

研究报道2008年河口植胶区橡胶林内出现细足捷蚁,随后2009、2010年发生面积扩大,对人、橡胶树造成伤害;介绍细足捷蚁种类鉴定、形态、生物学习性和防治试验结果。     

生物防治效果评价初探

对生物防治的概念、内容、优缺点及生物防治的评价指标进行了概述。     

海参皂苷的分离提取与生物活性

海参具有较高的营养价值和药用价值.海参皂苷具有抗肿瘤,抗菌等多种生物活性,具有重大的应用价值和广阔的应用前景.本文对海参皂苷的提取、分离纯化、分析方法及生物活性进行初步的介绍.     

基于模糊层次分析法的生物燃气产业竞争力评价模型及应用

随着中国能源需求的不断增长和环境保护的日益加强,生物燃气产业越来越受重视,对产业竞争力进行评价以了解地区生物燃气产业发展水平成为急需解决的问题。该文从规模、经济、技术、管理、可持续发展5个方面选择了22个指标,构建了生物燃气产业竞争力评价指标体系。基于层次分析法和模糊综合评判法,提出了生物燃气产业竞争力评价模型,并应用于北京市生物燃气产业竞争力评价。评价结果表明:规模竞争力在差的隶属度综合得分是0.49,制约因素主要是从业人员人数及气体总消费量。经济竞争力指标在中的隶属度综合评分是0.65,制约因素主要是农民增收情况。技术竞争力指标在良的隶属度综合评分是0.54,制约因素主要是人才吸引力情况。管理竞争力指标在中的隶属度综合得分是0.54,制约因素主要有运营管理模式及技术安全管理水平。可持续发展竞争力指标在优的隶属度综合得分是0.51。北京市生物燃气产业竞争力属于中等水平,在废弃物资源化利用能力以及污染物减排方面具有明显优势,在科研投入、技术装备方面具有较高水平,在管理水平、经济效益、产业规模方面等方面处于中等或较差水平,需要进行完善和提升。模型很好的表征了北京市生物燃气产业的现状,研究结果可为北京市生物燃气产业发展提供依据。     

蜡样芽孢杆菌菌株X5强化的生物有机肥能有效控制根结线虫(Meloidogyne sp.)

The efficacy of Bacillus cereus X5 as a potential biological control agent against root-knot nematodes was evaluated in vitro by examining second-stage juvenile mortality and egg hatching rate under addition of culture filtrate and in planta by application of bio-organic fertilizers enhanced with B. cereus X5, B. thuringiensis BTG, or Trichoderma harzianum SQR-T037 alone or together in greenhouse and field experiments. The biofumigation of the root-knot nematode-infested soil with organic materials (chicken manure, pig manure and rice straw) alone or in combination with B. cereus X5 was also conducted in greenhouse experiments. In laboratory, the filtrate of B. cereus X5 more effectively reduced egg hatching rates during the incubation period for 14 d and more effectively killed the second-stage juvenile during the incubation period of 24 h than that of B. thuringiensis BTG. The highest dry shoot weights for greenhouse tomatoes and field muskmelons were found in both the treatment consisting of the bio-organic fertilizer enhanced with the three biocontrol agents and the treatment consisting of the bio-organic fertilizer enhanced only with B. cereus X5. The two bio-organic fertilizers achieved better nematicidal effects than those enhanced only with B. thuringiensis BTG or T. harzianum SQR-T037. B. cereus X5 also enhanced effect of biofumigation, which resulted in increased plant biomass and reduced nematode counts in the roots and rhizosphere soil. Therefore, these results suggested that biological control of root-knot nematodes both in greenhouses and fields could be effectively achieved by using B. cereus X5 and agricultural wastes.     

Absorption spectra of humic acids

For the purpose of explaining the forming process of soil humic acids, the author determined the absorption spectra of various humic acids. From soils and peats which were pretreated with 5% HCl at 70°C for 30 minutes or from those which were not, humic acids were extracted by treating with 0.5% NaOH at boiling temperature for 30 minutes. In these humic acids, the one which is extracted after acid pretreatment is provisionally designated as SrL humic acid and the other as L humic acid. The supernatant alkaline solutions obtained by centrifuging the above mentioned extracts were acidified with hydrochloric acid, and precipitated humic acids were filtered and washed with water until Cl' free. Humic acids were dissolved in 0.1% NaOH and ultrafiltered using collodion membrane. The filtrates were acidified with hydrochloric acid and humic acids were collected by centrifuging, transferred on the filter paper, washed with dilute hydrochloric acid and water successively, then air-dried and pulverized.     

Studies on the properties of organic matfer in buried humic horizon derived from volcanic ash

To investigate the relationship between the change of humus property and time factor, the humus composition in the buried humic horizons with the age from 28,000 years B.P. to the present was studied, according to the method presented by Kumada et al. (7).

The fH decreased with the elapse of time and in case of most of humus in the buried humic horizons with the age over 10,000 years, the fH became lower than 40 and were in the form of so-called ‘combined’ humus.

When 3,000-4,000 years have passed since the surface soil buried, the humic acid first moved . to ‘combined form.’ Second, after over 10,000 years, the fulvic acid moved to ‘combined form.’

The humification of ‘free’ humic acid proceeded with the elapse of time till around 5,000 years but of 'combined' humic acid till around 7,000 years. Both the humification-degree of ‘free’ humic acid after around 5,000 years and of ‘combined’ humic acid after around 7,000 years decreased. The humification-degree of ‘free’ and ‘combined’ humic acid from the samples with the age about 15,000 years B.P. to 28,000 years B.P. may be the same.