Analysis of the Effect to the Water Quality of Xiao River for Kaixian County Sewage Discharge After the Sluice of the Three Gorges Reservoir

Once the water level of the reservoir of the Three Gorges rises above 175 m, Yangtz River in Kaixian County will be changed into a lake-like reservoir which will be rare in the Three Gorges areas, and water pollution would be seriously deteriorated. In order to testify whether water quality meets the requirements of the function divisions, two-dimension water dynamics quality model and homogeneous-mixed water quality model are used to simulate polluted water disposal of Kaixian County before and after sewage purification. The analysis indicates that sewage disposal without any pretreatment will cause serious and continuous pollution; while sewage disposal after purificaiton up to standard, there are two kinds of results: in abundant and normal period , the water quality improves obviously, the water quality can meet the function of river area, but in dry seasons, the water quality improvement is not so effective, and still exceeds the control standard of the water function. To guarantee water quality of Xiaojiang River, it is proposed that, first, sewage treatment plant should run normally and continuously; second, other measures must be added to control sewage discharges in dry season.     

Research on the Method of Water Pollution Control Planning

The definition, history and development process of water pollution control planning are introduced in this paper. The new methods of water pollution control planning based on GIS and ANN technology are introduced as well. At present, the water resources shortage and water environment pollution have restricted the development of the society and economy, so the improvement of the standard of water pollution control will be benefit for the sustainable utilization of the water resources.     

再生水灌溉对作物及土壤安全性影响研究进展

中国水资源供需矛盾突出,农业灌溉用水尤为紧张,合理利用再生水进行农田灌溉是未来农业灌溉发展的趋势。再生水既是水源、肥源也是污染源,若使用不当会对作物和土壤造成负面影响。在对国内外相关资料进行分析的基础上,从作物生理生长、土壤理化性质、重金属污染、卫生学指标四个方面,对国内外再生水灌溉的研究现状进行了总结分析。研究发现,再生水灌溉研究主要存在三个方面的问题：国内大部分再生水灌溉试验周期短,缺乏长期观测;新型灌水技术和灌溉方式在再生水灌溉上的应用较少;关于再生水灌溉对土壤病原菌污染方面的研究较少。建议加强长期再生水灌溉试验、再生水灌溉下不同灌溉方式和灌水技术以及不同灌溉方式下再生水灌溉对土壤病原菌和重金属分布特征和累积规律的研究工作。     

云南省嵩明县污水处理厂对污染物处理效果的分析

为了更好地评价云南省嵩明县污水处理厂运行效果,对该污水处理厂运行1年来进出口水质、污泥处置等情况进行调查分析。结果表明,该污水处理厂对废水BOD、CODcr、SS、TP、NH4-N的平均去除率分别为81.45%、78.78%、86.08%、41.37%、84.03%。该污水处理厂污泥处理符合环保及农用要求,对环境没有造成污染;恶臭等问题也得到了有效的控制。试验及调查结果对污水处理厂的设计及其后期运行具有重要的指导意义和实用价值。     

国道309线周边植物表型可塑性浅析

公路周边的植物受到交通污染后,在响应异质性生境的过程中,会出现表型方面的改变。基于国道309线周边植物多样性调查,对各样地植物的根长、株高、叶面积、根冠比等性状与土壤含水量、交通量和滞尘量进行测定和相关性分析,结果表明：样地内植物种类主要有茵陈蒿、灰绿藜、艾草、野老鹤草及复盆子5类,其中优势种为茵陈蒿、灰绿藜和艾草。样地公路段系双车道二级公路,路侧植物的路距与灰绿藜的叶片滞尘量关系紧密;样地土壤含水量与植物表型可塑性指标呈现一定的相关性,即随着含水量减小,植物根长、叶面积、根冠比及植物多样性指数均增大,但株高减少。样地中不同植物的根长、株高、叶面积和根冠比等表型可塑性指标也差异明显,表现出对异质性生境不同的适应性。     

内生真菌与禾本科植物的共生机制研究进展

本文从物种的起源进化、生理学、化学生态学等角度阐述了内生真菌与禾本科植物的共生机制。此类共生体起源于植物致病真菌的一个分支,即生活史具有高度可塑性的有性型Epichloё属真菌经过种间杂交、失去有性生殖能力后的Neotyphodium属真菌与禾本科植物形成了专一性、互利共生程度更高的共生形式。Neotyphodium真菌获得了宿主植物更有效的保护和传播,同时产生更多的生物碱,使得植物抗性增加,竞争能力更强;内生真菌可作为一种生物异源物质在植物内部诱导某种胁迫预警机制,使得植物在环境胁迫来临时更快、更有效的进行气孔调节、渗透调节,同时真菌释放的激素和生物碱可保持植物较高的水分利用效率、维持根系生长以及保证植物的生长不受影响。长期来看,内生真菌-禾草共生体将改变土壤的营养元素水平,降低植物群落的生物多样性,改变食草动物的取食行为,进而影响食物链的能量流动和食物网结构,进而对生态系统产生不可低估的作用。     

池塘循环水养殖系统构建及其生态净化效果研究进展

传统水产养殖模式易造成水体污染、水资源浪费等问题,影响鱼类生长。为达到健康养殖的目的,池塘循环水养殖系统在循环经济理念指导下,通过利用动力流水净化与生物修复技术,采取建立人工湿地等措施净化水体,形成一套可持续发展模式。本研究综述了该系统的3种主要模式的构建及其水质净化效果,分析该系统运行中出现的主要问题。现有研究表明,不同模式下对TN、TP、NH4+-N、CODMn、NO2--N等水质指标平均去除率基本维持在60%。同时,分析了系统中养殖池塘与净化单元面积配比关系的计算、净化单元中基质与植物以及PH、温度等对净化效果的影响。本研究通过对这些研究的总结与讨论分析,将为深入对池塘循环水养殖系统的研究提供参考资料。     

沿海滩涂发展能源植物的潜力分析

发展生物质能源对缓解中国的矿质能源压力、减轻能源污染具有重要意义。在分析了发展生物质能源的迫切性的基础上,介绍了利用中国丰富的沿海滩涂土地资源和植物资源开发能源植物的潜力。同时,从滩涂资源的有效利用、盐生植物中能源植物的发掘和通过转基因技术提高能源植物耐盐性及改良盐生植物生产能源物质的特性等方面提出了沿海滩涂发展能源植物的资源潜力。     

Analysis on Cause of the Eutrophication of Water Body

Based on mechanism of eutrophication, the cause of eutrophic formation in water is analyzed in this paper. The analysis is made from the level of nutrients (nitrogen and phosphorus), content of iron and silicon, illumination intensity, temperature, water dynamics (stream of water and wind power) and period of renewal. The purpose of the analysis is to provide a reference to keep a balance of ecology in water, control the water pollution and prevent eutrophication of water.     

Environmental conditions during root development: Drought constraint on cassava starch quality

Cassava has the reputation of being a drought tolerant crop, however, when deprived of water, plant and root development are affected. This ultimately will translate to an altered starch synthesis expressed by variation of starch quality. The magnitude of which, is influenced by the severity of stress conditions and stage of plant maturity. During early plant development,water stress retards growth, which will only be resumed after the immature plant has received sufficient water. Despite of an increased starch yield, the effect of initial water stress on starch quality is still sustained. In mature plants, starch quality is affected by environmental conditions prior to root harvest, especially the onset of rain after a stress period as indicated by a reduced starch paste. This paper presents the argument for extending the scope of traditional breeding programs beyond selecting for plant growth under drought conditions, to strategies that place greater emphasis on stabilizing starch quality. This revised version was published online in July 2006 with corrections to the Cover Date.     

植物对氮素吸收利用的研究进展

摘要： 本文对近年来植物对氮素吸收的研究进展进行了详细的阐述,从氮素对植物生长发育的影响、植物对氮素利用的生理机制和分子机制三个方面进行了总结,旨在为植物营养育种提供一定的理论依据,从而实现提高植物氮素利用效率的目的。     

河岸带生态系统管理模型研究进展

（西南大学资源与环境学院,重庆数字农业重点实验室,重庆 400716）     

土壤植物系统硒累积迁移的影响因素及调控

硒是一种对动植物以及微生物比较重要的元素。硒元素供给不足或者过量都会引起地方病的发生,如克山病和大骨节病就有可能与缺硒有关。目前有大量学者对土壤中硒的有效性、植物对硒的吸收和植物中硒的转运以及影响因素进行了全面深入的研究。笔者从土壤硒有效性以及植物对硒吸收两方面,综述了土壤质地、pH、有机质、氧化还原特性、植物种类、施肥、成土母质以及综合污染对土壤-植物系统中硒的迁移转化的影响及其机制,阐述了目前研究中出现的问题和不足,对未来需要进一步深入的研究提出了建议和展望。     

糖调控植物根系生长发育的研究进展

根系是植物生长发育必不可缺的器官,不仅起到固定、支持植物的作用,还能从土壤中吸收植物生长发育必需的水分和无机盐。在植物根系生命活动中糖充当着营养成分和信号分子的双重作用,且与植物激素作用影响根系生长发育。近年来,国内外学者对糖调控植物根系生长发育做了大量研究,笔者综述了糖对根系生长发育的影响,介绍了糖信号转导及糖信号转导调控根系生长发育的机理,并从糖与植物激素的共同作用方面总结了糖调控根系生长发育机理的研究进展,以期为后续糖调控植物根系的相关研究提供参考。     

小东江污染段滨岸植物与生态恢复

对污染较严重的小东江茂名段的滨岸植物进行了初步调查,共录得维管束植物31科67属77种。发现外来入侵植物25种,占调查种数的32.47％,应引起注意。在5个调查地点中,彭村、乌石和旧村的植物组成较好,市总排和官渡桥的植物组成较差,滨岸植物的组成与水体污染的程度有关。竹叶草、星毛蕨、芋、大马蓼、水蔗草等适应性较强的非入侵植物对小东江生态恢复具有重要意义;另外,也推荐了其他一些抗污染力强的水生或湿生植物以供参考。     

周期性淹水对消落区水土环境的影响及控制对策

三峡库区消落区生态脆弱,在水土交互作用下消落区土壤母岩风化成土进度加快、土壤侵蚀加剧、土壤氮磷等营养物质及重金属大量溶出,其中N、P、COD和重金属是主要的溶出因子,淹没的耕地是主要的污染源。成库初期消落区生态脆弱性增强、水土流失加剧、地质灾难增加、岸边污染加重,尤其在水流缓慢的库湾将会出现局部的富营养化现象;随着消落区稳定的库岸湿地生态系统的形成,水土耦合呈现正的环境效应。为了尽快构建健康的消落区生态系统,防止三峡库区消落区水土环境的退化,必须加强和发挥政府宏观调控职能、建立消落区土地保护区域、推广复合生态技术并做好库区污染防治与修复工作。     

Water use efficiency of crops cultivated in the Mediterranean region: Review and analysis

Improvement of water use efficiency (WUE) of field crops in the Mediterranean region is an imperative imposed by the critical situation of water resources of the region, as well as by the demographical increment. This review reports the experimental data concerning WUE of 16 species cultivated in the region. The species include cereals, leguminous, horticultural and industrial crops. This review however underlines that WUE data of fruit trees are lacking, despite they represent one of the main productions of the Mediterranean agriculture.

In this region, the large range of WUE values observed, for the same species, can be ascribed mainly to: (i) fertilizers and water management (water regime, mineral supply and water quality); (ii) plant factors (species, variety and sensitivity of growth stage to the stress); and (iii) environmental factors (climate, atmospheric pollution, soil texture and climate change). The conclusion highlights the actual gap concerning WUE in the Mediterranean region. This gap will constitute a field of research designated to ameliorate WUE of agriculture in this region.     

三峡库区次级河流污染现状与对策研究

沉水植物金鱼藻和黑藻在治理三峡库区次级河流水体污染具有广阔前景,对保护三峡水库的水环境贡献很大,在库区水体中可以发挥强大的环境生态功能。本文通过分析三峡库区次级河流的环境问题,预测了金鱼藻和黑藻在库区的应用前景,即防止水体富营养化、有机物污染、重金属污染、抑制藻类生长,以及维持生物多样性、生态完整性和稳定性。     

中国蝶类多样性威胁因子分析

蝴蝶越来越受到诸多人为以及自然因素的影响,直接或间接地威胁蝴蝶繁殖、生长、羽化、交配等正常生长过程,从而对蝴蝶种群发展造成不利影响。蝴蝶的主要威胁因子有环境污染、栖息地破坏、农药喷洒、人为捕捉,这些威胁因子对蝴蝶威胁巨大,不仅降低蝴蝶种群数量,可能导致某些蝶种灭绝;蝴蝶的次要威胁因子有寄主植物破坏、放牧、旅游开发、城市化、气候变暖等人为因子,还包括低温、洪水、天敌危害、蝴蝶自身因素等自然因子,这些因子是导致自然界中蝴蝶越来越少,是蝴蝶正常生存的制约因素。     

Coupling Diffusion Simulation of Volatile Pollutant in the Water and Air

Spill of volatile poisons into natural water bodies causes water pollution and then air pollution arises from water pollution because of volatilization. In order to explain the coupling of water pollution and air pollution, the dimensionless Henry constant of volatile poisons was used to establish coupling diffusion model based on compressed VOF method and the double film theory explained for volatilization. A high resolution bounded differencing scheme for arbitrarily unstructured meshes was applied to simulate coupling diffusion of trichloroethylene and tribromoethylene. The simulation results are in good agreement with those from single phase model. The influence of environmental temperature, wind velocity and the dimensionless Henry constant on the mass transfer across gas liquid interface was analysed.