海西东部及环青海湖地区40多年的气候变化研究

利用1961～2004年地面观测资料,分析了海西东部及环青海湖地区年、季气候变化的特征和规律。结果表明,海西东部及环青海湖40多年来年季平均气温平均增温幅度为0．3～0．6℃,平均最低和最高气温多数季节增温具有非对称性。并且20世纪90年代四季增暖最为明显。夏季和冬季降水略有增加,而过渡季节降水变化基本呈减少趋势。年均和秋、冬、春、夏四季的气温变化倾向率均为正值．分别为0．48、0．57、0．692、0．337、0．373℃／10a。冬、夏季降水变化的倾向率为0．442、4．672mm／10a;而秋、春季了水变化的倾向率为-2．304、-0．022mm／10a。冬季降水量和累计积雪量的缓慢增加容易导致该地区地表积雪的积累,极易形成雪灾或低温冻害。春季气温升高、降水减少。干旱发生的频次将增加;秋、冬季气温上升幅度比较大．将有利于病虫害的越冬、繁殖,加重病虫害对农牧业生产的危害程度。     

黄浦江上游近自然混交林和人工纯林水源涵养功能评价

以上海黄浦江上游水源涵养林为研究对象,选择近自然混交林、香樟(Cinnamomum camphora)人工纯林和无患子(Sapindus mukorossi)人工纯林,对比了地上部分、枯落物层、土壤层三个垂直层次的持水量,综合评价了其水源涵养功能。结果表明:地上部分持水量近自然混交林与香樟纯林持平,大于无患子纯林,分别为16.36t/hm2,16.85t/hm2,12.54t/hm2;枯落物层最大持水量依次为近自然混交林(0.37t/hm2)无患子纯林(0.004t/hm2)香樟纯林(0.003t/hm2);土壤层最大持水量近自然混交林(2 657.02t/hm2)无患子纯林(2 526.81t/hm2)香樟纯林(2 474.80t/hm2)。土壤层对森林涵养水源功能的贡献最大,但同时离不开地上部分及枯落物层三者间的相互依存和影响。综合评价得到不同类型林分的总持水量为近自然混交林(2 673.73t/hm2)无患子纯林(2 539.35t/hm2)香樟纯林(2 491.65t/hm2)。由此可见,林分复杂、树种多样、林下植被丰富的近自然混交林涵养水源的能力最强,优于单一的无患子纯林,而香樟纯林最差。     

Chemical speciation of copper and manganese in solution of a copper-contaminated soil and young grapevine growth with amendment application

Copper(Cu)-based fungicide application to control foliar diseases in grapevine(Vitis vinifera L.) can increase soil Cu availability. Brazilian soils have high natural Cu and manganese(Mn) concentrations, increasing the potential for toxicity to grapevine plants. Application of amendment substances can reduce the concentrations of toxic chemical species of Cu and Mn in soil solution, especially for the soils grown with young plants. We evaluated the chemical speciation of Cu and Mn in soil soluti...     

浙江天童冬青属植物的种群结构及更新类型

为加强冬青属Ilex植物资源的保护和利用,采用标准样方法调查分析了浙江宁波天童4种冬青种群结构及更新类型。结果表明:1所调查群落共出现木本植物61种,除草本层外,林木层由下至上可分为灌木层和乔木层,其中在乔木层之上存在分别由小果冬青Ilex micrococca,马尾松Pinus massoniana,天童锐角槭Acer acutum构成的不连续的超高层。2所调查冬青属植物的年龄结构可分为4种类型:增长型(皱柄冬青Ilex kengii),稳定型(铁冬青Ilex rotunda),成熟型(冬青Ilex chinensis)和衰退型(小果冬青Ilex micrococca)。3冬青属植物总体生长良好,但有些种如小果冬青属于衰退型,无幼苗,无萌枝,种子更新困难,冬青幼苗难以通过环境筛导致幼树严重匮乏,需要采取适当人工育种以及栽培技术来加以繁殖保护,并对优良种质加以选育和利用。     

经营强度对毛竹林植物多样性的影响

对由天然针阔混交林或天然阔叶林经过人为改造和抚育转变成的4类毛竹林(即成林原因相同的4种林型—强度干扰下的毛竹纯林,较强干扰下的竹杉混交林,较弱干扰下的竹阔混交林,弱度干扰下的竹杉阔混交林)的层次结构、物种组成、物种丰富度、α多样性及群落相似性经营强度对毛竹林植物多样性的影响进行了对比分析。结果表明:这4种人工毛竹林随着经营强度的加大,层次结构逐渐简单化,乔木层、灌木层和草本层的物种丰富度迅速下降,且物种组成发生显著变化。乔木层、灌木层和草本层的生物多样性总体也呈下降趋势,但灌木层和草本层的生物多样性竹阔混交林类型反倒略高于经营强度最弱的竹杉阔混交林类型。而且不同经营强度下所形成的这4种类型毛竹林的群落相似性也随着经营强度的增加而降低,其中毛竹纯林与其他3类的相似性最低。     

响应面法对金银花中绿原酸提取工艺的优化

为优化金银花中绿原酸提取率的最佳工艺条件,在单因素试验的基础上,应用Box-Behnken中心组合设计研究了乙醇质量分数、水浴时间、微波温度3个独立因子对金银花中绿原酸提取率的影响,再利用响应面分析法优化提取工艺条件。结果表明:绿原酸微波辅助提取最佳工艺条件为微波功率400W,微波温度58℃处理70 s,料液比1∶25,乙醇质量分数72%,60℃水浴加热51 min。经实际提取验证,绿原酸提取率为4.643 mg/g。     

Joint Acaricidal Action of Diafenthiuron and Fenbutatin-oxide Against Tetranychus cinnabarinus （Boisduval） （Acari： Tetranychidae）

[Objective]This study was conducted to obtain a new high-efficiency acaricide mixture.[Method]The synergism acaricidal of diafenthiuron and fenbutatin-oxide against carmine spider mite was investigated,and the optimal ratio of both acaricides were determined by means of co-toxicity factors and co-toxicity coefficients（CTC）.[Result]At 24 h post-treatment,the LC50values of diafenthiuron and fenbutatin-oxide against T.cinnabarinus female adults were 154.67 and 93.26 mg/L,respectively,and the synergistic mass ratios of diafenthiuron and fenbutatin-oxide ranged from 1：0.06 to 1：0.87,and the optimal diafenthiuron-to-fenbutatin-oxide ratio was 1：0.39 with the LC50and CTC of 67.87 mg/L and 188.93（CTC significantly above 100 strongly indicated synergism）,respectively,and the toxicity relative to diafenthiuron and fenbutatin-oxide was 2.28 and 1.37 times,respectively.[Conclusion]The joint acaricidal action of diafenthiuron and fenbutatin-oxide strongly indicates synergism.These findings proved scientific theoretical basis for mixing diafenthiuron and fenbutatin-oxide to control spider mites and developing a new synergisic acaricide.     

Novel Colloidal Interactions in Anisotropic Fluids

Small water droplets dispersed in a nematic liquid crystal exhibit a novel class of colloidal interactions, arising from the orientational elastic energy of the anisotropic host fluid. These interactions include a short-range repulsion and a long-range dipolar attraction, and they lead to the formation of anisotropic chainlike structures by the colloidal particles. The repulsive interaction can lead to novel mechanisms for colloid stabilization.