多层抽屉式循环水幼鲍养殖系统及养殖效果

为了提高皱纹盘鲍的养殖效果,该文设计了多层抽屉式循环水养殖幼鲍系统,分析了养殖期间系统的水质指标和耗能量,及不同养殖密度下幼鲍的生长率和成活率。结果表明,该系统适宜的幼鲍养殖密度为150个/屉(70cm×40cm×10cm/屉),为流水式养鲍密度的6～9倍。试验过程中水温、溶解氧、pH值、盐度、NH4+-N和NO2-N指标均达到幼鲍生长条件,NH4+-N和NO2-N体积质量基本稳定在0.023～0.065mg/L和0.014～0.041mg/L范围内。试验期间总耗电量为688.88kW·h,其中海水加热占总耗电量19.62%,相当于每天1.287kW·h耗电量,大约是流水式养殖加热耗能的1/7。该研究表明,多层抽屉式循环水养鲍系统是一种安全、高效、节能减排的养殖模式。该系统可供选择养鲍设施时参考。     

循环水养殖旋转式生物流化床生物过滤功能

生物过滤是循环水养殖水处理的关键,生物过滤功能启动以及操作条件直接影响到生物过滤的效果。该文以实验室规模旋转式生物流化床为研究对象,采用自然挂膜法研究海水和淡水生物过滤功能的启动;设置了3个膨胀率50%、75%、100%和4个C/N0、0.5、1.0、2.0,研究其对旋转式生物流化床处理养殖污水效率的影响。结果表明:1)以氨氮和亚硝态氮浓度降低并稳定为判断标准,淡水和海水系统旋转式生物流化床生物过滤功能启动完成分别需要47和60 d;2)污水处理效率随膨胀率增大而提高,该研究膨胀率为100%时处理效率最高,总氨氮转换率高达881 g/(m3·d);3)C/N增大,抑制生物膜的硝化功能,污水处理效果变差,C/N大于2.0时污水处理效果显著变差。该研究可为旋转式生物流化床在应用过程中生物过滤功能的启动和日常操作管理提供技术指导。     

斑节对虾循环水养殖系统构建与运行试验

为探索斑节对虾循环水养殖可行性及应用发展价值,该研究自主设计蛋白分离组合装置、内循环流化床等关键工艺环节水净化装备,构建了技术先进、结构紧凑的斑节对虾循环水养殖系统。针对其不同阶段生长特性及水环境需求,提出一种水质调控方法,科学投喂。运行试验120d,溶解氧浓度5.30～7.14mg/L,p H值7.23～8.44,氨氮浓度0.43～1.38 mg/L(稳定运行后),亚硝酸盐氮浓度0.15～0.56 mg/L(稳定运行后);斑节对虾在循环水养殖模式水生态环境下正常生长,先后经历快速生长期、稳定生长期及缓慢生长期,终末养殖密度3.02 kg/m2,取得高效养殖结果;终末饲料系数1.67,单茬每平方米利润34.78元,每平方米年利润69.56元(按1年2茬计),获得良好经济效益。该实践可为斑节对虾循环水养殖模式应用提供技术支持。     

紫外线对水产养殖循环水的杀菌效果

为了研究循环水水产养殖系统紫外杀菌的效果,在循环水系统中对单灯管紫外装置杀灭养殖水中粪大肠菌群的效果进行了试验,研究了紫外灯功率、循环水流速和水的紫外光线透射率对杀菌效果的影响。结果表明,单位水体的紫外线功率越大,杀菌效果越好;水体通过紫外灯杀菌器的流速越大,单次通过杀菌器的杀菌量减少,但由于水体循环次数增加,总杀菌效果加大;254?nm紫外线透射率越大,杀菌效果越好。在理论分析和试验数据的基础上,建立了循环水紫外线杀菌系统的模型,并得到了粪大肠菌群的一价失活系数为0.0062?m2/J。对失活速率常数较小的菌群,增大紫外灯功率杀灭效果较好,而增加日循环次数杀灭效果提高不明显。该研究的结果可为循环水系统紫外线杀菌系统的设计和运行提供依据。     

淡水珍珠蚌循环水养殖模式下分布式水质监控系统设计

为促进中国淡水珍珠养殖业由传统粗放模式向高效生态智能化改造升级,该研究针对珍珠蚌工厂化循环水养殖模式下的水质监控需求,开发了基于无线传感网络的分布式水质监控系统。系统采用感知层、传输层和应用层相结合的体系架构,由水质监测节点、气象监测节点、设备控制节点和监控中心组成。现场采用多参数传感器、ZigBee无线模块、可编程逻辑控制器(Programmable Logic Controller,PLC)和MCGS触控屏组合的方式,实现对多地点监测数据的实时采集、图形化显示和报警功能,对循环水处理设备的启停控制及藻类供饵自动控制功能;上位机采用MCGS网络版和SQL Server数据库构建监控数据中心。系统采用无线组网分布式架构,组网灵活且操作简单,简化了设备的安装和维护工作。经实际使用测试,系统工作稳定性和检测准确性均在98%以上,能够满足淡水珍珠蚌循环水养殖的监控需求,可以为珍珠蚌传统养殖模式的转变和产业生产方式的转型升级提供有利保障。     

超高密度全封闭循环水养殖系统设计及运行效果分析

为进一步研究循环水养殖系统在高密度养殖生产过程中的水质变化情况、鱼类生长情况及应用推广价值,该文构建了一套超高密度全封闭循环水养殖系统,设计3条水处理环路,集成了鱼池双排水、竖流沉淀、转鼓式微滤机、移动床生物过滤、多腔喷淋式纯氧混合装置、二氧化碳脱气等高效水处理技术和装备。提出一种基于投饲量的循环水养殖系统设计计算方法,重点考虑氨氮、溶解氧和总悬浮颗粒物3个水质指标。使用该系统养殖吉富罗非鱼6个月,试验研究结果显示:鱼类生长情况良好,最高养殖密度104.2kg/m3。饵料系数1.4,成活率92.2%。水质检测结果显示:氨氮浓度维持在平均(1.09±0.55)mg/L;溶解氧维持在4～9mg/L范围内;pH值6.45～7.41。经济性分析研究结果表明,系统养殖运行成本约为25元/kg,略高于市场价格。但是,从环境成本考虑,系统的节水效果显著,日耗水仅为0.3～0.5m3。通过适当的精简并挑选合适的养殖品种,完全可以实现规模化的生产。     

海水循环水养殖系统生物膜快速挂膜试验

循环水养殖系统生物膜的挂膜成熟是一个比较耗时的过程,通常需要30～40d。为解决这一技术瓶颈,该文在一个大型海水循环水养殖厂的生物滤池内进行了生物膜快速挂膜的中试试验。该养殖厂循环水养殖系统有并联的生物滤池4个,单个为跑道式2级串联结构,总容量为800m3,采用毛刷状聚乙烯丝为生物载体。试验设计为预先培养水质净化菌的种子液,制备经200目筛绢过筛后质量比为4:1的黏土和沸石粉超细颗粒混合物悬液,然后按103cfu/mL和5g/L的浓度在两级滤池中分别加入4种不同水质净化菌的种子液和"黏土-沸石粉"混合物悬液,静水充气培养8d后,生物载体上能够形成较为牢固的生物膜。打开循环水系统运行2d后,连续5d检测生物滤池进、出水口的氨氮、硝酸盐、亚硝酸盐和COD(化学需氧量)含量,其5d平均消除率分别为:52.04%、17.24%、26.82%和62.94%。结果表明,与传统生物膜自然培养方法相比,该文所采用的挂膜方法将海水循环水养殖系统生物膜的挂膜成熟提前了20d以上,起到了增速效果,在生产上也是可行的。     

基于物质平衡的循环水养殖系统设计

针对工厂化循环水养殖系统中快速去除水中的溶解性氨氮和增加溶解氧等系统设计的核心问题,采用物质平衡关系建立氨氮、溶解氧的平衡方程式,推导出系统设计的计算公式,并根据工程实践的经验对部分公式进行了修正,得到了一组较贴近实际情况的设计参数,如：系统补水量、供氧量、循环量、循环次数、生物过滤器有效体积等。同时构建了一个工厂化循环水养殖系统设计的基本流程。以设计一套年产50 t鮰鱼（Ictalurus）,养殖密度为50 kg/m³的高密度工厂化循环水养殖系统为例,可以计算得到系统的补水量为30 m³/d,系统补水率为6%,系统供氧为11.0 kg/h,系统循环量740 m³/h,循环次数为36次/d,生物过滤器有效体积为44.2 m³。     

封闭循环系统对虾合理养殖密度的试验研究

2002年5月～8月在室内工业化养殖温室内进行了高密度封闭循环水养殖凡纳滨对虾(Litopenaeus vannamei)试验，采用人工配制海水(盐度为4)，养殖排放水经过滤、消毒、增氧处理后循环利用，日添加新水量为总循环水量的3%～7％。经86 d养殖，对虾体重从(0.3±0.04)g/尾增加到(10.40±2.04)g/尾，平均产量为5.85 kg/m³，饵料系数为1.76，成活率为67％，该封闭循环养殖系统设计合理，每m³水体放养约1029尾对虾较适宜。     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.     

Effect of some fungicide seed treatments on the survival of Bradyrhizobium japonicum and on the nodulation and yield of soybean [Glycine max. (L) Merr.]

Several commercial fungicide seed treatments were evaluated for their possible effect on the survival of Bradyrhizobium japonicum on seeds and on the nodulation and yield of soybeans in a greenhouse and a field experiment. quinolate Pro (carbendazim and oxine copper), Vitavax 200FF (carboxin and thiram), and Monceren (pencycuron) had a small effect or no effect on the survival of B. japonicum and on the nodulation and yield of soybeans. They can thus be considered compatible with soybean seed inoculation. Germipro UFB (carbendazim and iprodione), Apron 35J (metalaxyl), and Tachigaren (hymexazol) decreased B. japonicum survival and the nodulation and yield of soybeans and thus cannot be considered compatible with soybean seed inoculation.     

Einfluss der düngungsmethoden auf die entwicklung von zuckerrübenkrankheiten

Während neunjähriger (1994-2002) Untersuchungen in der Versuchsanstalt Ba?cyny (Fahlerde, Fall-Gleyboden, ausgebildet aus leichtem Lehmboden) wurde der Befall mit Krankheiten an der Zuckerrübe in Abhängigkeit von der Düngungsmethode bewertet. Folgende Methoden wurden angewendet: A - Mineraldünger, B - Stalldung und Mineraldünger, C - Stroh-, Gründung und Mineraldünger, D - Kompostdünger und Biopräparate (ökologische Düngung). Auf den Objekten A, B, C wurden bei konstanter Phosphor-Kalium-Düngung die Stickstoffgaben von 0 bis 180 kg.ha^?1 differenziert. Auf dem ökologischen Objekt D ohne Mineraldünger wurden statt Stickstoff die Biopräparate P₅₀₀ und P₅₀₁ verabreicht. Der geringste Befall von Krankheiten wurde an der Zuckerrübe auf jenem Objekt festgestellt, das mit Kompost und den Biopräparaten gedüngt worden war. Im Rahmen der konventionellen Düngungsmethoden wurde allgemein die höchste Intensität der Krankheiten an der mit Stroh, Gründung und Mineraldünger gedüngten Zuckerrübe beobachtet. Ausnahmen von dieser Regel bildete das Vorkommen von echtem Mehltau und Keimlingsfäule. Auf den Objekten A, B, C nahm die Intensität der Krankheiten mit der Steigerung der Stickstoffgabe zu. Auch die auf Objekt D verabreichten Biopräparate stimulierten die Entwicklung der Krankheiten. The effect of various fertilization methods on the diseases of sugar beet was estimated on the basis of nine-year studies (1994-2002) conducted in the Experimental Production Farm in Ba?cyny on loess-based, sedimentary-gley, light-clay soil. The following fertilization methods were applied: A - mineral fertilization, B - mineral and manure fertilization, C - straw, green manure and mineral fertilization, D - ecological compost and biodynamic preparations fertilization. In the objects A, B and C fertilized with phosphorus and potassium, various doses of nitrogen ranging from 0 to 180 kg/ha^?1 were used. In the ecological object D, where mineral fertilization was not used, biodynamic preparations P₅₀₀ and P₅₀₁ were applied instead of nitrogen. The lowest ratio of the diseases of sugar beet was observed in the object fertilized with the compost and biodynamic preparations. In view of the conventional fertilization methods, generally the highest incidence of diseases was noted in the sugar beet fertilized with straw, green manure and mineral fertilizers. The exception was the occurrence of powdery mildew and the black leg. In objects A, B and C the incidence of the diseases increased with the increase in nitrogen doses. The applied biodynamical preparations in the object D stimulated the development of diseases too.     

Prospects for control of Pythium damping-off of lettuce with Trichoderma,Gliocladium and Enterobacter spp.

Summary Damping-off of lettuce (Lactuca sativa) caused by Pythium ultimum was studied in pots containing a non-sterile potting mix in the glasshouse. Fifty P. ultimum sporangia g^-1 compost reduced the plant stand to 15% and shoot dry weight to 18%, but this reduction was totally prevented by applying Trichoderma harzianum at 2×10⁵ viable propagules g^-1 potting mix. Gliocladium virens and Enterobacter cloacae also alleviated the damping-off. E. cloacae did not adversely affect the action of the fungal antagonists. The co-existence of the bacterial and fungal antagonists was revealed on the root surface and inner surface of the testa by scanning electron microscopy, indicating the compatibility of the biocontrol agents.     

细菌、真菌及植物氮营养信号研究进展

氮素吸收代谢是所有生物生命活动的核心部分,因此,各种生物对氮的吸收与同化过程都有精细的调节。这种调节依赖于生物对体内氮素状况信号及体外（生长介质中）氮素信号的感受。过去几十年中,在细菌、真菌中已经对氮素营养信号有了较好的研究,而植物中则相对缓慢,但也有了一定的认识。本文重点比较细菌、真菌及植物中氮信号系统的组成,以期为进一步认识植物中的氮信号接受与转导系统提供启示。     

Potential of wild species for genetic enhancement of some semi-arid food crops

Discovery and incorporation of genes from wild species provide means to sustain crop improvement, particularly when levels of resistance in the cultigens are low and virulent strains of pests and pathogens overcome the host plant resistance. The extent of utilization and the potential of the wild genepool for genetic enhancement were reviewed in five important food crops viz. sorghum, pearl millet, chickpea, pigeonpea and groundnut grown in the semi-arid tropics. Introgression from compatible wild germplasm in the primary gene pool resulted in transfer of new cytoplasmic male sterility systems in pearl millet and pigeonpea, development of high protein, cleistogamous flower and dwarf pigeonpea lines and foliar disease resistant groundnut cultivars. Utilization of wild species in secondary and tertiary gene pools has been generally limited due to sterility, restricted recombination or cross incompatibility. Nevertheless, these species are extremely important as they contain high levels of resistance to several important biotic and abiotic stresses. Several of them, like those belonging to the Parasorghum section and the rhizomatous Arachis species are sources of multiple resistances and hold great promise to sustain crop productivity.     

“绿色革命”以来大气CO2浓度升高对C3作物营养品质的影响

自20世纪60年代"绿色革命"以来,育种技术和农耕技术的发展促进了农作物产量的大幅提升,然而作物的营养品质出现下降趋势。在相似的遗传背景下,大气CO_2浓度升高会使单位体积农作物产品的营养元素含量下降,因此"绿色革命"至今,农作物产品的营养元素下降可能受大气CO_2浓度升高影响。通过植物生长箱模拟"绿色革命"初期和目前的大气CO_2浓度水平(310μmol/mol和400μmol/mol),针对主要C_3作物水稻、小麦和大豆,研究"绿色革命"以来大气CO_2浓度升高对其籽粒的C、N、Fe、Zn元素含量的影响,结果表明:CO_2浓度升高对3种作物籽粒的C元素含量几乎没有影响,变化幅度在±1.5%之间;籽粒的N、Fe、Zn元素含量普遍呈现下降趋势,但均未达到显著水平。