南荻对土壤铅污染的耐性与吸收积累研究

通过土壤盆栽试验,研究了不同浓度梯度pb2＋胁迫下南获整个生长发育周期的生长、土壤理化性状的变化以及不同生长阶段的根系固定重金属含量变化的过程,结果表明：（1）种植南获植物的土壤pH值随着月份的变化呈减小趋势;（2）种植南获的土壤中铅随植物的生长逐渐减少;（3）南获对重金属铅的积累顺序为：根〉叶〉茎,对土壤中重金属的修复机理主要是通过根系固定作用。     

Effects of simulated acid rain on root growth of Cunninghamia lanceolata and Schima superba saplings planted in acidified soil

Results from pot culture (with one-year old Cunninghamia lanceolata and Schima superba) are described. It was found that the biomass production and elongation of C. lanceolata was seriously inhibited at pH 2.0 rain, but for S. superba, was not affected markedly. When pH values of experimental rain were higher than 2.0, the root growth of both species was not adversely affected. Aluminium had already accumulated to some degrees in the roots of both trees, and started to affect the root growth of C. lanceolata at pH 2.0 rain. The soil chemistry was also examined. Increased acidity of experimental rain increased the leaching of Ca and Mg. The Al/Ca mol ratio increased from 0.3 to 0.9 in top soil, and in rhizosphere to 1.5 when the pH values of simulated acid rain were 4.5 to 2.0. In this experiment, NO₃- fertilization effect was discovered.     

不同有机质含量的土壤中DDT对小麦根系的生物有效性

对不同有机质含量的土壤中，分别选用水、正己烷、正己烷／丙酮混合溶剂作为DDT的提取剂，用这3种提取剂逐级连续提取，研究了这3级提取剂所提取的DDT量的差别及其与小麦根吸收的关系。结果表明，有机氯的水提取量随土壤D0c的增加而上升，正己烷提取量随土壤TOC的增加而下降，正己烷／丙酮提取量随土壤TOC的增加而上升。根吸收与水提取量没有确定的关系，但与正己烷提取量具正相关关系，与正己烷／丙酮提取量有负相关关系。     

蚕豆根尖细胞微核法监测连云港市近海海水污染的研究

研究了用蚕虫根尖细胞微核技术监测海水污染的可行性，报告了用此法监测连云港市近海海水污染的实验结果。在与同期化学监测结果对比的基础上，提出了划分布污染等级的初步标准，对应用该法的意义进行了讨论。     

Rutabaga roots, a rich source of oviposition stimulants for the cabbage root fly

Summary. Two recently identified compounds ("CIFs"), present on the leaf surface of Brassica oleracea (cabbage), are the strongest oviposition stimulants known for the cabbage root fly, Delia radicum. Cabbage leaves contain these compounds in extremely low concentrations, and the amount of CIFs obtained from purifying leaf extracts was so small that it limited further research. We were able to purify far more of these two compounds from the roots of Brassica napus var. napobrassica (rutabaga). Apart from being a richer source of CIFs, rutabaga roots are considerably easier to collect and process than leaves. In addition, we isolated and identified a new CIF compound from the roots that is also very active in stimulating oviposition in the cabbage root fly. Received 26 May 2000; accepted 26 July 2000     

植物根系对土壤抗侵蚀能力的影响

以决定土壤抗侵蚀能力的土壤内在性质为表征指标，以长江中上游几种常见的水土保持林为对象，就植物根系对土壤抗侵蚀能力的影响机制和影响程度进行了研究．结果表明：植物根系能够提高土壤的抗侵蚀能力，且主要通过d≤1mm的须根发挥作用；其可能的机制是：活根提供分泌物，死根提供有机质，作为土壤团粒的胶结剂，配合须根的穿插挤压和缠绕，使土壤中直径d＞7mm、d＝7～5mm和d＝5～3mm3个大粒级水稳性团聚体数量增加，同时既增加了土壤的总孔隙度，又提高了土壤抗冲击分散能力和结构、孔隙的稳定性，从而提高了土壤饱和渗透系数．与无林裸地相比较，林地中表征土壤抗侵蚀能力的土壤各理化性质改善值（Y），与土壤中d≤1mm须根量（Rw）之间服从Y＝a＋bRw的线性关系．本文建立了相应的回归模型，并比较了不同林型根系的作用效果．     

蚕豆根尖微核技术监测环境致突变物的研究

本文应用蚕豆根尖微核技术对环境致突变物ＮａＮ３，ＨｇＣｌ２，Ｋ２Ｃｒ２Ｏ７进行诱变性研究，结果表明：ＮａＮ３，ＨｇＣｌ２，Ｋ２Ｃｒ２Ｏ７能明显诱发蚕豆根尖细胞微核率的增高，在一定范围内具有明显的线性剂量效应关系。说明该技术是监测环境致突变物的一种有效手段。     

Effects of two root-secreted phenolic compounds from a subalpine coniferous species on soil enzyme activity and microbial biomass

In order to evaluate the ecological consequences and potential mechanisms of specific C compounds on soil microbial processes under climate warming, we injected solutions of two modelled root exudates, 2,6-di-tert-butyl-4-methylphenol (BHT) and 1,2-benzenedicarboxylic acid, dibutyl ester (DBP), respectively, into soil at two concentrations (20 and 1000?µg?g^?1 soil). For all treatments, soils amended with the two phenolic compounds were incubated at two temperatures (20°C and 30°C) for 30 days. The responses of soil enzyme activity and microbial property to modelled root exudates to some extent depended on temperature regime, exudation component, and addition concentration. For example, the addition of BHT tended to decrease the soil enzyme activities. However, DBP addition generally increased the two metabolic enzyme activities at 30°C, and tended to decrease the two enzyme activities at 20°C, but a significant reduction was observed only at a high concentration at 20°C. The microbial biomass and enzyme activity were generally lower at 30°C compared to those at 20°C, when averaged across all treatment combinations. Taken together, our results indicated that the amounts and quality of liable root-derived C can differentially affect microbial processes, and various environmental changes will greatly complicate root–microbe–soil interactions in forests.     

三工河流域梭梭群落细根生长动态及周转

细根对植物群落功能的发挥和土壤碳库及全球碳循环具有重要意义.采用土柱法和分解袋法,于2010年5-10月整个生长季内,对三工河流域梭梭(Haloxylon ammodendron)群落的细根生物量以及分解和周转规律进行研究.结果表明,梭梭群落细根生物量呈现明显的季节变化,5-8月逐渐增加,8月达到最大,9-10月逐渐下降.细根生物量月平均值为183.76 g·m-2.活细根和死细根生物量分别占细根总生物量的72.59％和27.41％.梭梭群落细根生物量表现出明显的垂直变化,随土壤深度的增加而呈现先增加后逐渐降低的趋势,其中51.36％的活细根和51.81％的死细根生物量分布在＞10～30 cm土层.梭梭群落细根年分解率为58.76％,达到50％和95％分解率所需时间为279和1 302 d.梭梭群落细根净生产力为110.73 g·m-2·a-1,年周转速率为1.25次.     

薏米人工湿地根系分解及其铬元素的释放和化学形态变化

利用湿生植物薏米构建垂直流人工湿地,研究了不同浓度Cr6+(0、20、40 mg·L-1)处理对湿地植物薏米根系分解及铬元素含量和形态分布的影响,以期为研究根系中Cr的累积、形态转变及人工湿地高效处理含铬废水技术提供理论支持.结果表明:薏米根系前30 d分解快速,之后分解缓慢;20、40 mg·L-1Cr6+处理与对照相比,根系的分解速率分别降低了40.63%、55.56%.分解前期(0~45 d)根残体对Cr具有较强的吸附能力,分解后期(45~60 d)根残体吸附能力减弱,根残体的Cr含量为先升高后降低,分解60 d后根残体释放出Cr.分解过程中重金属活性较强的乙醇提取态(F1)和去离子水结合态(F2)的含量均显著降低;在分解60 d后,Cr6+胁迫下根残留体内Cr以醋酸提取态(F4)含量最高,其他形态次之;不处理Cr6+根残体内Cr以残渣态(F6)为主要优势,百分比高达76.76%.本研究表明,分解过程中根内Cr含量呈先增高后降低的趋势,Cr6+胁迫下降低了根系分解率,但没有提高Cr的生物活性.