短柄五加蒸腾作用及其与生理生态因子相关性的初步研究

水分是植物生长和分布的主要限制因子 ,因此对植物蒸腾作用特征及与环境因子关系的探讨一直是植物生理生态学研究的重要内容之一。短柄五加 (Ａｃａｎｔｈｏｐａｎａｘｂｒａｃｈｙｐｕｓ)是分布于我国黄土高原地区的濒危灌木树种 ,具有重要的药用价值。目前 ,已有关于短柄五加无性系种群生长和生殖生物学特征的报道 (田国伟等 ,1 998;王仲礼等 ,1 997;1 998ａ ;1 998ｂ ;1 999;岳春雷等 ,2 0 0 1 ) ,但对其生理生态学的研究尚为空白。本文通过对短柄五加在林下和开阔地两种生境下的蒸腾特征及与环境因子的相关性的比较研究 ,旨在从植物水分…     

基于Hyperion光谱信息的鲁西北盐碱地特性探析

利用Hyperion影像及盐碱地分布端元提取了鲁西北典型盐碱地光谱数据并对其特性进行了探析,以证实光谱信息对于该区盐碱地研究的可用性。利用生成的原始及包络线去除的光谱曲线,分别从土壤电导率、土壤盐分含量及一系列诊断性指标入手,借助诊断性吸收波段对本区盐碱地特性进行了分析。结果表明：该区盐碱地兼具其他地点盐碱地光谱吸收共性及自身特性,证实了基于遥感光谱信息的盐碱地特性分析是可行的,可用于区域盐碱地遥感监测。     

基于水平吸渗确定土壤水分扩散率的解析-修正法

准确测试土壤水分扩散率是研究水分在土壤中运移的关键之一.针对水平吸渗法测试土壤水分扩散率易受边界效应影响的问题,该研究构建解析-修正法,以提高测试结果的精度.假设第一类边界条件下,一维水平入渗Richards方程解的形式与其对应线性化方程的解析解相似,结合常数变易法,推导了一维水平入渗Richards方程的近似解析解....     

污染土壤的微生物修复原理与技术进展

微生物修复是土壤环境生物修复技术的重要组成部分,是最具发展和应用前景的生物学环保新技术.本文以土壤中重金属及典型有机污染物为对象,从土壤微生物与污染物质的相互作用入手,较为系统地综合评述国内外污染土壤的微生物修复原理与技术,并结合当前土壤污染的新特点,提出了需进一步认识和解决微生物修复过程中出现的新现象和新问题,以不断丰富和拓展土壤环境微生物修复范畴与内涵.     

砷污染土壤的蜈蚣草修复研究进展

本文评述了As污染土壤的蜈蚣草植物修复及其对As的解毒机制的研究进展,内容着重包括蜈蚣草对As的富集特征,As在蜈蚣草中的赋存形态、迁移及其转化,土壤以及土壤中P、Ca和K等元素对蜈蚣草吸收、转运As的影响等方面。     

土壤环境中多环芳烃的微生物降解及联合生物修复

研究土壤环境中持久性有机污染物的生物降解及其生物修复技术是当今国际环境修复科学技术前沿领域的重要课题。本文重点论述了土壤环境中持久性有机污染物多环芳烃的微生物降解机理及其在生物修复中的应用等,并结合当前研究进展,展望了基于多种修复措施相结合的多环芳烃污染土壤联合生物修复工程技术的开发与应用前景。     

不同分层土壤对锌的吸附解吸特性

为探究重金属锌在不同分层土壤中的吸附解吸特性,了解锌在分层土壤中的迁移规律,试验通过批量平衡试验,分析了锌在4个分层土壤(耕作层、犁底层、心土层、母质层)中的吸附解吸行为。结果表明:各分层土壤对锌的吸附动力学过程包括快速吸附、慢速吸附、吸附平衡3个阶段,准二级动力学方程对吸附过程的拟合效果优于准一级动力学方程,Langmuir方程能更好的拟合4种分层黑土对锌的等温吸附过程,4种土壤分层对锌的吸附能力由大到小的顺序为耕作层、犁底层、心土层、母质层,是因为随着土壤深度的增加,土壤有机质质量分数逐渐减小,4种分层土壤对锌的吸附能力逐渐降低。吸附热力学试验表明,随着温度的升高,各分层土壤对锌的吸附量均逐渐增大,ΔG<0(ΔG为吉布斯自由能的变化),ΔH>0(ΔH是标准焓变),ΔS>0(ΔS是标准熵变)说明了4个分层土壤对锌的吸附过程为自发、吸热、无序的过程。Zn的解吸量与吸附量呈正比,最大解吸量随着剖面深度的增加而减小,且均存在滞后效应。N、P质量浓度的增加,可以提高土壤固定Zn的能力,减小Zn对土壤农作物、地下水的重金属危害。     

巨菌草根际土壤微生物群落代谢功能多样性分析

【目的】研究福州平潭巨菌草根际土壤与非根际土壤微生物对不同碳源利用,明确巨菌草对根际土壤微生物功能多样性的影响,为巨菌草生态治理提供理论依据。【方法】在福州平潭基地采集巨菌草(Pennisetum giganteum)根际土和非根际土壤样品,采用Biolog-ECO 技术研究巨菌草根际土与非根际土壤微生物对不同碳源利用特性,揭示不同碳源利用的不同及影响差异的主要因素。【结果】与对照相比,巨菌草根际土壤微生物的代谢活性高于非根际土壤;多样性分析结果表明,与非根际土壤相比,巨菌草根际土壤样品的Simpson指数、Shannon指数、Brillouin多样性指数略高,差异不显著;主成分分析结果表明,对主成分一和主成分二贡献大的碳源种类分别为22 种和6种,糖类是巨菌草根际土壤微生物利用的主要碳源类型。【结论】与非根际土壤相比,巨菌草根际土壤微生物群落在碳源利用及代谢功能多样性高于非根际土壤。     

Bio-amelioration of alkali soils through agroforestry systems in central Indo-Gangetic plains of India

A long-term field study was initiated during 1995 at Central Soil Salinity Research Institute, Regional Research Station, Lucknow(26°47′58′′ N and 80°46′24′′ E) to analyze the effect of agroforestry systems on amelioration of alkali soils. Three agroforestry systems(pastoral, silvipastoral and silvicultural) were compared with the control where no agroforestry system was introduced. Tree-based silvicultural and silvipastoral systems were characterized by tree species Prosopis juliflora and Acacia nilotica along with grass species Leptochloa fusca, Panicum maximum, Trifolium alexandrium and Chloris gayana. Growth of ten-year-old Prosopis juliflora and Acacia nilotica planted in combination with grasses was significantly higher over the silviculture system with the same species. Tree biomass yields of P. juliflora(77.20 t?ha-1) and A. nilotica(63.20 t?ha-1) planted under silvipastoral system were significantly higher than the sole plantation of(64.50 t?ha-1 and 52.75 t?ha-1). Fodder yield under the pastoral system was significantly higher than the silvipastoral system during initial years but it was at par with that of silvipastoral systems after eight years of plantation. The microbial biomass carbon in the soils of silvipastoral systems was significantly higher than in soils under sole plantation of trees and control systems. The Prosopis-based silvipastoral system proved more effective in reducing soil pH, displacing Na+ from the exchange complex, increasing organic carbon and available N, P and K. Improvement in soil physical properties such as bulk density, porosity, soil moisture and infiltration rate was higher in the Prosopis-based silvipastoral system than in the silviculture system or control. On the basis of biomass production and improvement in soil health due to tree + grass systems, silvipastoral agroforestry system could be adopted for sustainable reclamation of highly alkali soils.     

Tracking the Trade in Ornamental Coral Reef Organisms: The Importance of CITES and its Limitations

The extraction of coral reef organisms for the aquarium and curio trade is reported to be contributing to coral reef degradation. The total international trade and associated impacts are unknown, because data are collected only for organisms listed on Appendix II of CITES, which include stony corals, antipatharians and giant clams. CITES data indicate that trade in live stony coral and reef substrate (live rock) increased by 15–30% each year during the 1990s, with most exports since 1992 from Indonesia and Fiji. Overall, 19% of all stony coral traded (by item) from 1985 to 1997 was live; 71kern-1pt% of this was traded between 1993 and 1997 (52% of total trade). Although tracking trade using information from the CITES Trade Database provides limited information (e.g., coral is reported to genus, and volume is reported by item or weight), the CITES mechanism promotes the development of strategies to protect resources. In response to CITES requirements, Indonesia developed a management plan for sustainable harvest of corals, but not for non-CITES listed species such as soft corals and fishes. Trade in hard and soft coral provides revenue for developing countries; however, in order to be of lasting value the industry must be developed with a conservation ethic. This requires support for international programs such as CITES, management plans for sustainable harvest, and improved enforcement.