添加槐花粉对白三叶青贮发酵品质的影响

采用单因子随机设计,研究添加不同比例的槐(Sophora japonica)花粉对白三叶(Trifolium repens)青贮发酵品质的影响,以期为槐花应用于青贮饲料生产提供科学依据.分别设置白三叶单独青贮(C)、95％白三叶+5％槐花粉青贮(T1)、90％白三叶+10％槐花粉青贮(T2)、85％白三叶+15％槐花粉...     

乱采滥挖野生药用植物对甘南草原生态环境的破坏

在实地考察和调查统计基础上,从甘南野生药用植物乱采滥挖时的表现,以及采挖野生药用植物造成草原植被破坏、水源涵养功能下降、药用植物资源可持续利用破坏和阻碍地方经济发展四方面,综合分析了乱采滥挖野生药用植物对甘南草原生态环境的破坏。提出运用经济和法律等手段,对甘南野生药用植物资源应进行适时、适地、留种和保护利用的原则,以遏制乱采滥挖现象,实现甘南草原野生药用植物资源的可持续利用。     

Floodplains of a regulated southern alpine river (Brenno,Switzerland): ecological assessment and conservation options

• 1. The fifth‐order southern alpine Brenno River and its floodplains are severely impaired by embankments, water abstractions and the construction of dams for hydropower generation. The river's annual mean discharge is reduced to 27% of the natural flow and the number of small (50–100 m³ s^?1) and medium‐sized (101–150 m³ s^?1) floods is reduced significantly.
• 2. Lateral hydrological connectivity has decreased strongly as a result of the flow regulation, whereas the significance of vertical connectivity has increased. The remnants of the middle and lower floodplains still contain springbrooks, ponds, and intermittently connected channels, which are all sustained by emerging groundwater.
• 3. Aquatic floodplain habitats can be classified partially by faunal composition. The lotic/lentic gradient appears to be a dominant compound factor structuring invertebrate assemblages when considering all aquatic habitats. The exfiltration of groundwater in conjunction with a reduced lateral connectivity enables the occurrence of many stenotopic species.
• 4. A comparison of present floodplains with those shown on historical maps shows that the fluvial landscape has changed markedly. The proportions of functional floodplain units characterized by autogenic succession and trends to late successional stages (i.e. senescence) have increased.
• 5. Floodplains of the Brenno river are still considered to represent important ecological areas and they are protected by law. Whilst the legislative protection of floodplains is the basis for conservation, this does not include the restoration of driving hydrological processes. An annual release of small‐ and medium‐sized floods could generate a diversity of disturbances, thereby promoting rejuvenation and counteracting senescence.
• 6. Alternative conservation options that circumvent ongoing contracts of water use, though generally promising, are limited because of the operation of hydropower schemes. At present the exfiltrations of groundwater mitigate the impacts of flow regulation on the ecological integrity of the floodplains.

Copyright © 2002 John Wiley & Sons, Ltd.     

A preliminary study of water use strategy of desert plants in Dunhuang,China

Water is a restrictive factor for plant growth and ecosystem stability in arid and semiarid areas. The dynamics of water availability in soils and water use by plants are consequently critical to ecosystem functions, e.g. maintaining a high resistance to the changing climate. Plant water use strategies, including water-use efficiency(WUE) and the main water source that a plant species utilizes, play an important role in the evaluation of stability and sustainability of a plantation. The water use strategies of desert plants(Tamarix chinensis, Alhagi sparsifolia, Elaeagnus angustifolia, Sophora alopecuroides, Bassia dasyphylla and Nitraria sphaerocarpa) in three different habitats(saline land, sandy land and Gobi) in Dunhuang(located in the typical arid area of northwestern China) were studied. The stable isotope of oxygen was used to determine the main water source and leaf carbon isotope discrimination was used to estimate the long-term WUE of plant species in the summer of 2010. The results suggest that: 1) the studied desert plants took up soil water below the depth of 80 cm; 2) T. chinensis in the three habitats used deeper soil water and T. chinensis in the Gobi site had higher WUE than those in the saline land and the sandy land. The results indicated that desert plants in Dunhuang depended on stable water source and maintained high WUE to survive in water limited environments.     

一种水产养殖用微生物制剂的研究

利用枯草芽孢杆菌、干酪乳杆菌、沼泽红假单胞菌和啤酒酵母4种菌株配制了一种复合微生物制剂,试验结果表明,该制剂除含有丰富的营养成分外,在水产养殖中还能起到净水剂的作用,它能增加水中的溶解氧,显著降低氨氮、亚硝态氮、硫化物等不利于水产养殖的污染成分。此微生物制剂在水产养殖中将能发挥营养、保健及净化水质的功效。     

基于野外实测高光谱数据的干旱区耕作土壤含水量反演研究

利用2011年3月野外实地采集的不同含水量土壤的高光谱数据,研究了南疆地区耕作土壤草甸土含水量与高光谱反射率之间的定量关系,构建了一元线性回归与多元逐步回归的土壤含水量预测模型.结果表明,土壤含水量在380～ 1080 nm波段与反射率呈负相关关系;反射率经倒数(1/R)、对数(logR)、一阶微分(R’)变换后可提高其与含水量的相关性;以50个建模样本所建立模型的相关系数均达到极显著水平,所有模型通过对37验证样本进行预测,比较决定系数、均方根误差、相对误差后,表明多元逐步回归模型的预测能力要优于一元线性回归模型,从所有模型中优选出以698、702、703、746、747 nm波段反射率倒数(1/R)建立的多元逐步回归模型为最优模型,该模型实测值与预测值之间的R2为0.9199,RMSE为1.6026,RE为0.6517,可用于基于野外高光谱数据的土壤含水量的估测.     

湖北省钟祥市南湖水生态环境评价

位于湖北省钟祥市城关郢中镇东的南湖,面积800hm^2,集观赏和水产养殖于一体。鱼产量为700t／a。该湖紧靠城市,直接纳人了未经任何处理的大量生活和工业污水,每天流量达40000t,造成水体严重富营养化,鱼类因栖息环境恶化而大量死亡,造成很大经济损失。鉴于此,笔者对南湖水生态环境进行了调查,旨在为南湖的综合治理提供科学依据。     

三峡水库试验性蓄水后小江沿岸水质研究

根据2010年3月－12月对三峡水库小江沿岸水体的水质监测数据,分析总氮、总磷、化学需氧量和叶绿素a等水质因子的时空变化规律,以及叶绿素a与水质因子之间的相互关系,评价水体富营养化水平。结果表明：总氮、总磷、化学需氧量和叶绿素 a含量分别为1.980±0.119mg/L、0.114±0.018mg/L、9.520±1.748 mg/L和23.342±8.810 mg/L,小江沿岸水体呈现中度富营养化水平。叶绿素a与水质因子间的相关关系分析发现,叶绿素a含量与温度、pH、溶解氧、亚硝酸氮和化学需氧量显著相关,与总氮、总磷不具有显著相关性。这说明小江沿岸水体叶绿素a含量与总营养盐无关,而主要与水体所含的有机质含量有关。     

淡水养殖环境中氨氧化微生物的研究进展

随着水产养殖业的快速发展,养殖水体氮素污染日益突出,硝化微生物在水产养殖环境氮循环中具有重要作用。本文主要综述我国淡水养殖环境中硝化微生物的多样性、作用机理、厌氧氨氧化过程和机理等研究进展,并展望今后的研究工作:(1)淡水养殖水域硝化作用和氨氧化微生物的时空分布特征及影响因子;(2)淡水养殖环境氨氧化微生物及其他氮素转化关键微生物的过程与机理;(3)深入研究特定生态系统中如池塘生态系统、氮循环的各个过程,构建相关氮素转化和氮素平衡模型,为完善淡水池塘生态系统氮循环理论、水产养殖环境的氮素污染治理和生态修复提供参考。