纤维素降解菌L-06的筛选、鉴定及其产酶条件的分析

从用于堆肥的水稻秸秆中初筛出一株高效纤维素降解菌L-06, 根据18S rRNA基因序列和菌株形态分析, 初步鉴定该菌为斜卧青霉(Penicillium decumbens)。研究了液体发酵培养基中氮源、碳源、表面活性剂、培养温度、起始pH以及接种量对该菌株各纤维素酶活力的影响。在最适条件下, 该菌的b-葡萄糖苷酶(BGL)、外切纤维素酶(CBH)于培养第3天酶活力分别达到1662 u/mL和2770 u/mL; 内切纤维素酶(EG)、滤纸糖化力(FPase)于培养第4天酶活力分别达到18064 u/mL和4035 u/mL。在产酶优化实验中, 该菌的EG和CBH在pH10的培养条件下分别保持了70%和43%的酶活性; 在50oC培养条件下EG和CBH分别保持了68%和59%的酶活性。表现出了耐热, 耐碱的特性。     

农药对土壤微生物的生态效应

大量有关农药对土壤微生物生态效应的研究表明,虽然有些农药对土壤微生物及其活性会产生抑制或促进作用,但这种作用一般是短暂的;按推荐浓度正常使用农药通常不会影响土壤微生物的各种生化过程和活性,对土壤的物质循环和土壤肥力也没有不利影响;但大多数土壤薰蒸剂和杀真菌剂能改变土壤微生物平衡,它们对土壤微生物的作用强于杀虫剂和除草剂;长期使用农药不致使土壤微生物数量和活性发生明显变化,这应部分归功于土壤微生物对农药的降解或转化．     

The role of saltwort (Batis maritima L.) in regeneration of degraded mangrove forests

While saltwort (Batis maritima L.) is common in the fringe mangrove forests of southwest Florida, its role in regeneration of degraded mangrove communities is not known. Given the potential encroachment and subsequent degradation of mangrove communities by sea-level rise, it is important to quantify the effect of early-colonizing vegetation to early mangrove seedling survival. A greater number of mangrove seedlings were observed in existing B. maritima patches compared to surrounding mudflats. A planting experiment was designed to determine whether B. maritima was responsible for the observed pattern. Black mangrove (Avicennia germinans L.) seedlings, raised in a nursery, were planted in previously established B. maritima patches and on mudflats with and without nursery-raised B. maritima. There was significantly lower mortality of A. germinans seedlings when planted in existing B. maritima patches (69%), compared to seedlings planted on the mudflats (93%), demonstrating that existing B. maritima improved A. germinans seedling survival. Nursery-raised B. maritima had lower mortality on open mudflats (28%), suggesting that it can tolerate conditions, which make it an early colonizer of newly available habitats. The primary mechanism proposed for improving seedling success is a slight increase in elevation provided by the dense root network of established B. maritima. These findings have implications for scientists and managers anticipating the response of mangroves to sea-level rise.     

城市生态用地分类及其规划的一般原则

城市生态用地的规划布局是城市规划的难点之一,也是急待解决的问题.本文根据城市生态系统的特点,给出了城市生态用地定义,指出城市生态用地同时具有自然属性和社会属性,依据这个特点,将城市生态用地划分为服务型生态用地和功能型生态用地两大类型,并结合具体的城市生态规划对各种类型的生态用地规划进行了定性分析.     

广东大宝山矿区生态环境退化现状及治理途径探讨

根据对广东大宝山矿区的实地调查、测试和所采集土、水样品的化学分析结果,对该区生态环境退化和向下游排放污染物现状进行报道.矿坑似乎是大宝山矿最重要的污染源地,据有限土壤样品分析结果推算,当其所含无机还原态硫彻底氧化后,平均1t矿坑表土可产出207kg浓硫酸.大部分矿坑表土和排土场废土已经历不同程度的酸化.实验室模拟试验显示:5g强烈酸化的矿坑表土在接力水提条件下可产出超过750mL的酸性“矿水”(pH<3.9).实测数据表明:排入翁江支流的矿水,其酸度大大超过国家规定的排放标准,大多数重金属元素的浓度也超过了国家规定的污水综合排放标准的最高允许值.从技术的角度来看,对大宝山矿区生态环境退化和向下游排放污染物状况的治理,宜采用环境地球化学工程与生物修复技术相结合的综合治理方法.     

Effects of food supplementation on home-range size, reproductive success, productivity and recruitment in a small population of Iberian lynx

In a conservation context, food supplementation is a management tool used to reverse the decline of food-limited populations by means of positive changes in behaviour and fitness that may be reflected in population parameters. The critically endangered Iberian lynx Lynx pardinus has suffered a dramatic decline primarily because of the severe drop of its main prey, the European wild rabbit Oryctolagus cuniculus . To reverse this situation, a food supplementation programme has been implemented in Doñana, south-west Spain, since 2002. In this study, we assess the utility of providing artificial food to reduce home-range (HR) size, and to increase productivity, survival and recruitment in a scenario of low lynx density, as compared with reference data from the same population in the absence of extra food. Food supplementation produced a significant contraction of core areas, but not of complete lynx HRs. We did not detect any significant change in productivity or dispersal rates, but supplementation could have helped transient adult lynx to settle down. The positive effects of food supplementation may have been partly countered by factors such as inbreeding, Allee effects and disease outbreaks, whose effects may have been exacerbated in this small lynx population. Food supplementation, however, proved useful to retain individuals, to keep range sizes within their normal range of values, thus maintaining spatial organization, and to allow lynx reproduction and kitten survival in areas with very low prey density. Therefore, we recommend keeping an extensive and intensive supplementary feeding programme until the density of wild rabbits will enable the viability of this endangered lynx population.     

有蹄类动物营养状况的测定方法及其评价

营养状况对于动物的生存和繁殖至关重要,是有蹄类动物种群管理的前提条件之一。文章综述了有蹄类动物营养状况的几种主要测定方法,简要介绍了这些方法的理论前提、基本模型、适用范围,并评价了它们的优缺点及如何提高其准确性的方法和途径。     

操作条件对生物质催化热解产轻质芳烃的影响

以轻质芳烃苯、甲苯、二甲苯以及萘（BTXN）为目的产物,采用双颗粒流化床对松木进行了催化热分解实验。讨论了催化剂CoMo-B加氢催化作用下,静止床高、流化气速、床层压降的相互关系,得到了一个合适的操作条件,为热分解实验提供了必要的基础实验数据。在热分解实验中,调查了操作气速、床层高度以及热解温度对产物收率和分布的影响,得到了中间产物苯、甲苯、二甲苯和萘等轻质芳烃化合物最高收率为6．3％下的最佳操作条件：催化剂为CoMo-B,气速2．0cm／s,床层高度为0．08m,热解温度863K。     

岱海水质咸化过程中若干生态因子的变化

在1996年夏季对岱海的综合调查基础上,结合自50年代以来关于岱海的地理学、水文学和水生生物学资料,对岱海水质咸化中的若干生态因子进行了比较分析,结果表明:目前岱海pH值为933,这已经接近生物适应范围的最上限;总碱度也逐年增长,而且增长极为明显;氯离子的含量也已经远远超过了1000mg/L的极限指标。上述变化清晰地说明,岱海的水质咸化过程正在加强。同时,钙镁比率越来越失调,水的硬度也不断增加,这些变化对渔业生产十分不利。