浅谈转基因技术对生物多样性的影响——从转基因食品谈起

科学技术的快速发展有时候真的是令人忧喜交加。转基因技术作为一种高科技技术,由于其蕴涵着巨大的市场和商机,目前正在全球范围内发挥着重要作用。但转基因技术与生俱来的安全不确定性与风险性也成为人们的困扰。科学家们对于转基因技术的应用对生态环境的影响一直存在着激烈的争论。由于科学知识的有限性、生态环境的复杂性以及转基因技术的新颖性,科学在转基因作物对生物多样性问题上还没有定论。     

接合子细胞强化对生物反应器降解2，4-D效应研究

研究了接合性质粒pJP4在2株纯菌E．coliDH5α、Alcaligenes sp．及好氧颗粒污泥混合菌群中的水平转移情况,并以获得pJP4质粒的接合子Alcaligenes sp．：：pJP4为强化菌种,考察了接合子细胞强化对好氧颗粒反应器和生物膜反应器中难降解有机物2,4-二氯苯氧乙酸（2,4-D）的去除效应．结...     

Comparing results of cultured and uncultured biological methods used in biological phosphorus removal

Increasing attention has been paid to phosphate-accumulating organisms(PAOs)for their important role in biological phosphorus removal.In this study,microbial communities of PAOs cultivated under different carbon sources(sewage,glucose,and sodium acetate) were investigated and compared through culture-dependent and culture-independent methods,respectively.The results obtained using denaturing gradient gel electrophoresis(DGGE)of polymerase chain reaction-amplified 16S rDNA fragments revealed that the diversity of bacteria in a sewage-fed reactor(1#)was much higher than in a glucose-fed one(2#)and a sodium acetate-fed one(3#);there were common PAOs in three reactors fed by different carbon sources.Five strains were separated from three systems by using a phosphate- rich medium;they were from common bacteria isolated and three isolates could not be found in DGGE profile at all.Two isolates had good phosphorus removal ability.When the microbial diversity was studied,the molecular biological method was better than the culture-dependent one.When phosphorus removal characteristics were investigated,culture-dependent approach was more effective. Thus a combination of two methods is necessary to have a comprehensive view of PAOs.     

中国生态保护政策的县域经济效应——来自国家重点生态功能区的证据

为保障生态产品供给，中国设立了限制开发的国家重点生态功能区，建立了生态保护转移支付制度.本文首次在县域层面构建2002~2017年县级面板数据，运用倾向得分匹配法构造政策组的“反事实”情形，基于双重差分法评估重点生态功能区政策的县域经济效应.结果表明，该政策提高了县域财力、长期来看一定程度改善了产业结构；以标准财政缺口为主的资金分配机制弱化了县域经济发展激励，资金补助不能完全抵消限制开发对县域经济带来的负向影响；固定资产投资和内资企业受影响较大.随着投入资金累积、生态产品价值的转化，该负向效应随时间而减弱、经济促增效应逐渐显现.政策效应在不同生态功能和经济区位间表现出明显的异质性.建议持续增加生态转移支付资金、将生态产品供给数量和质量作为资金分配依据，考虑按生态功能类型设计差异化政策，更好激励县域生态产品高水平供给与经济价值实现的双赢，促进区域均衡发展.