历史时期(着重近4kaB.P.以来)南疆地区气候环境与人地关系演化的初步研究

南疆地区近四千年来气候与环境演化的研究表明 ,本地区气候环境的干旱状况持续未变 ,但期间仍有若干次相对凉湿与暖干旱时期的波动 ,且揭示出 3 .0 ka B.P.、2 .0 ka B.P.、1.5 ka B.P.、1.0 ka B.P.、0 .2 ka B.P.五个气候突变转干时间界线。本研究揭示了近四千年来本地区持续干旱化的特征 ,并有后期加剧的趋势 ,并指出历史时期南疆地区若干人文事件的发生如近两千年以来丝绸之路的兴衰、南疆古城镇的废弃等与气候环境演化之间存在着良好的准对应关系 ,表明气候环境的自然演化是影响人地关系类型与内容的重要因素之一。     

17种蔬菜中铅铬镉元素含量分析研究

采用先进的分析技术——原子吸收光谱法测定了陕西省大中城市郊区的17种蔬菜 ,15 2个样品中的铅、铬、镉含量。并用翔实的测试数据分析了蔬菜中的铅、铬、镉含量及分布特征。结果表明 :铅是我省蔬菜中的主要污染元素 ,所检测的 17种蔬菜中 ,有 9.9%蔬菜样品的铅含量超出了国家卫生标准的允许量 ;铬和镉只发现在个别蔬菜上有污染 ,超标率分别为 1.3 %和 2 .0 %。西安市是我省蔬菜重金属污染较严重的地区 ,超标率为 10 .7% ,汉中市和咸阳市只发现在个别蔬菜上有重金属污染 ,超标率分别为 5 .0 %和 3 .9% ,宝鸡、渭南和铜川三市蔬菜无一超标 ,合格率为 10 0 %。从而探明了我省蔬菜中重金属的污染状况 ,分析了重金属污染的来源并提出了相应的防治对策     

柴达木盆地锂资源开发

随着科学技术的发展,锂及其化合物的用途越来越广,世界各地锂产品的需要量逐年增加,价格越来越高。青海柴达木盆地有着丰富的盐湖锂矿资源,大力开发锂及其化合物产品,对于振兴青海经济将会起巨大推动作用。本文从锂的应用、柴达木盆地及世界锂盐资源、市场需求、提锂工艺及盆地盐湖锂盐资源开发的可行性进行探讨。     

苏云金杆菌D—1(血清型H3ab)新菌株的研究

D—1菌株系从自然死亡的灯蛾虫尸分离的一株苏云金杆菌新菌株。经菌种鉴定与Bt.var.kurstaki相同,属血清Ⅲ型。其培养特性表现为:对培养基成分和培养温度适应范围较小,在温度28-30℃,培养基含固量为4.1-6.7％,C/N为5.7-6.2时发酵正常。32℃以上和浓培养基则影响其正常繁殖。这与HD-1菌株相吻合。对菜青虫、棉铃虫、玉米螟和松毛虫等4种昆虫毒力测定结果表明,D—1菌兼有H_5型青虫菌81—6和H_3型HD-1的杀虫特性。它对菜青虫和松毛虫的毒力与81—6相接近而高出HD—12.7—5.1倍。对棉铃虫和玉米螟的毒力则明显高于81—6也比HD—1强。     

中国西北荒漠植物区系信息系统

在对中国西北荒漠植物区系的 ６８ 个科、３６１ 个属、１０７９ 个种植物的分布区类型、性状、生境、产地等进行系统调查及研究的基础上,建立中国西北荒漠植物区系信息系统。本文介绍了该信息系统的结构及其功能,对该系统的使用范围及使用方法作了详细的说明     

匀鞭蚜小蜂成蜂扫描电镜观察

1990年因广东省松突圆蚧危害严重,故特从日本冲绳岛及面垣岛引进天敌日本异花角蚜小蜂以繁殖防治,同时,笔者在日本的松突圆蚧Hemiberlesia Pitysophila Takagi中发现另一种寄生蜂匀鞭蚜小蜂Encarsia sp.其生活史及防治情况将另文介绍.本文介绍电镜下该蜂的形态.     

塔里木沙漠公路防沙体系建设几个问题的探讨

沙害主要取决于两个系统因素的共同作用 :动力系统—风力和响应系统—下垫面状况。塔里木沙漠公路沿线风沙地貌形态类型复杂多样 ,沙源充足 ;起沙风频数高 ,作用时间长 ,防沙难度极大。已建成的高立式芦苇阻沙栅栏和 1 m× 1 m半隐蔽芦苇草方格固沙沙障结合的“阻固”体系 ,有效控制了沙害 ,但也存在一定问题。定位观测表明 ,沿线起沙风和输沙方向集中于 NE、ENE、E三个方向 ,占 46%～ 68% ,从理论上说 ,应加大风侧 (路东侧 )防护力度 ,而实际上固沙带内部强烈的风蚀与沙埋过程 ,使其有效年限与设置宽度关系不明显 ,宜采取窄宽度勤维修原则 ,上风侧宽度控制在 3 0 m～ 40 m,每 3～ 4年更新一次并及时维修。下风侧可不设置高立式沙障 ,固沙带宽度控制在 1 0 m～ 1 5 m为宜 ;高立式沙障与半隐蔽方格沙障前沿之间空留宽度控制在 8H以内较为适宜。依沙害程度 ,以单一原状芦苇固定沙障、复膜沙袋阻沙体活动沙障及固定沙障与活动沙障有机结合加强前沿阻沙力度 ;不同沙害部位设置不同规格不同高度的半隐蔽方格沙障、固化路肩边坡创造输沙断面等技术 ,形成立体防护体系 ,足以控制沙害。     

寄生玉米的6种腐霉及其致病性研究

 从国内12省、自治区、直辖市玉米植株上分离出腐霉菌菌株,依据形态特征、培养性状、生长抑制温度,以及产生的有性与无性器官,鉴别出6个腐霉种:棘腐霉(Pythium acanthicum Drechsler),瓜果腐霉(P.aphanidermatum(Edson)Fitzpatrick),强雄腐霉(P. arrhenomanes Drechsler),禾生腐霉(P.graminicola Subramaniam),肿囊腐霉(P.inflatum Matthews),寡雄腐霉(P.oligandrum Drechsler),其中肿囊腐霉出现频率高,分布广泛。回接玉米表明,腐霉能够侵染玉米并引起病害,肿囊腐霉、禾生腐霉、强雄腐霉、棘腐霉是玉米青枯病的重要致病菌;瓜果腐霉能够引起玉米中部茎节腐烂;寡雄腐霉虽寄生玉米,但对玉米成株无致病力。     

Transfer of chlorinated hydrocarbon insecticides and polychlorinated biphenyls from particles to membranes studied by quenching of fluorescence

Hydrophobic chlorinated hydrocarbons are adsorbed onto particles in the environment. Thus, uptake of chlorinated hydrocarbons into organisms is likely to be from the particle-adsorbed state. We investigated the transfer of chlorinated hydrocarbons from particles to phospholipid membranes, quantified by quenching of the fluorescence of a carbazole-labeled phospholipid which was used to label the membranes. The chlorinated hydrocarbons studied included DDT, DDE, methoxychlor, lindane, stirofos, and several polychlorinated biphenyls. The particles studied were porous glass, kaolinite, cellulose, and silica. Transfer of chlorinated hydrocarbons from particles to vesicles was independent of the chlorinated hydrocarbon concentration. The transfer rate did not depend on binding of lipids to particles, and was independent of the lipid composition of the vesicles. Membrane uptake of chlorinated hydrocarbons from the particle-adsorbed state was more rapid than uptake from the microcrystalline state, and uptake was faster when the chlorinated hydrocarbons were dispersed over larger particle surface areas. The transfer rates of chlorinated hydrocarbons correlated with their aqueous solubilities. In total, these results indicate that chlorinated hydrocarbons are transferred through the aqueous phase. We judge the rate-limiting step in membrane uptake to be the rate of solubilization of the chlorinated hydrocarbons from the particles into the bulk aqueous phase. Adsorption of chlorinated hydrocarbons onto particles may enhance the transfer rate by dispersing the chlorinated hydrocarbons and making them more available for solubilization in the bulk aqueous phase. The data are correlated with a model that assumes diffusion across an unstirred aqueous layer which interfaces with the bulk aqueous phase and the particle.     

内蒙古草原退化群落恢复演替的研究 Ⅳ.恢复演替过程中植物种群动态的分析

本文根据 1 983-1 993年退化草原群落恢复演替过程中主要植物种群地上现存量与密度的变化 ,将这些种群区分成 6种类型 :优势增长型—羊草 (Leymuschinensis) ;缓慢增长型—大针茅 (Stipa grandis) ;典型衰退型—糙隐子草 (Cleis-togenes squarrosa)和变蒿 (Artemisia commutata) ;迟滞衰退型—冷蒿 (Artemisiafrigida) ;中间过渡型—米氏冰草 (Agropyron michnoi)、双齿葱 (Allium bidenta-tum)和洽草 (Koeleria cristata) ;演替中立型—小叶锦鸡儿 (Caragana microphyl-la)。并依据各种群的拓殖 ,生物产量和根系分布等生物学特性分析了各种群在恢复演替中的作用。根据种群根系分布范围与种群密度变化的关联 ,本文提出“恢复演替的作用域扩展”概念。在过度放牧导致草原退化演替中 ,表现出群落地上部分矮化和地下部分的浅层化 ,恢复演替则表现其逆过程。当恢复演替开始后 ,浅层土壤中最先出现拥挤 ,浅根性植物种群趋于衰退 ,也促使一些种群向土壤深层发展。表现出种群更替的作用空间扩展的趋势。其中衰退种群植株死亡后的资源空间可使拓殖能力强的种群或原种群增长。于是资源与种群增长构成一个反馈调节环。反馈调节使群落演替自组织过程表现出方向性。在恢复演替过程中各种群的数量指标均表现出波动性     

菜豆种子普通细菌性疫病菌检测

 由Xanthomonas axonopodis pv. phaseoli和Xanthomonas fuscans subsp. fuscans引起的菜豆普通细菌性疫病是严重影响菜豆生产的限制因子之一,可造成严重的产量和品种损失。染菌种子是病原菌传播的主要途径。本研究对5个菜豆主要产区的60份菜豆种子样品进行普通细菌性疫病菌检测。在MT选择性培养基上有36份种子样品浸提液检测到目标病原菌, 种子样品带菌量为2.49×10²~5.20×10⁷ CFU/粒。选择36个分离物接种感病品种“英国红”植株,所有分离物均引起接种植株发病。特异PCR检测结果表明,有20个分离物为X. fuscans subsp. fuscans,16个分离物为X. axonopodis pv. phaseoli。试验结果表明,我国一些菜豆主产区商业种植和研究用种子多数污染普通细菌性疫病菌,建议建立无菌种子生产区和加强种子管理,以有效控制病害发生。     

西北干旱区土壤的生态特征与变化

本文利用详实的资料,分析了干旱区主要土壤类型、分布及其生态意义,土壤的理化性状、养分特征以及在盐碱化、沙化和灌耕条件下的变化,并论证了这种变化在生态功能上的影响。其结果表明：①干旱土壤分布具明显空间垂直地带性及径向分布规律。极端干旱条件下的暖温带棕漠土的生态功能最差,其他土壤的生态功能排序依次为灰棕漠土＜ 灰漠土＜ 灰钙土（棕钙土）＜ 灌耕土＜ 草甸土类;②土壤生态性能在灌耕,风沙及盐碱化条件下发生显著变化,耕灌条件下使高生态性能的土壤逐渐退化而低生态性能土壤有所改善;盐碱化和风沙化的结果使土壤贫瘠化和粗质化,生态性能严重退化;干旱区平原土壤的生态特征与变化规律决定了其具有潜在荒漠化倾向。对干旱区土壤和生态特性及其变化的认识,是干旱区水土资源合理利用与生态保护的基础     

黄瓜感染枯萎病后病理组织学的研究

 用病毒RNA (TMV RNA),寄主mRNA (烟草mRNA)及植物核糖体,建立了离体核酸核糖体反应体系及分析监测方法。测定了TMV RNA,mRNA与核糖体结合的饱含量及竞争系数。将此体系用于筛选植物病毒病选择性治疗药剂,并用原生质体,整株植物进行生测,检测离体筛选结果,测定了分子结构不同的抗病毒药物的选择性常数,分析了离体试验,原生质体试验及整株试验中的药物筛选阈值。     

A total-continuous portal vein fistula in gastrointestinal and toxicology research

A method for the total collection of portal vein blood over extended periods has been developed. The method has been applied in gastrointestinal toxicology research involving rats. The method facilitated quantitative recovery of portal vein blood for 120 min for measurement and identification of absorbed radiolabeled components derived from a toxic lipphilic pesticide placed in the lumen of the small intestine. The method can be applied to any substance—nutrient, anutrient, xenobiotic chemical, or endocrine factor—absorbed into the portal vein from the gastrointestinal tract. The method (a) provides for collection of compounds absorbed from the gastrointestinal tract before distribution to nondigestive tissues (i.e., liver), (b) allows measurement of the compounds absorbed without the need to monitor flow rate, and (c) facilitates accumulation of sufficient material from the total portal circulation for analyses when submicrogram quantities are absorbed. The latter two features are important but impossible to attain with small samples of portal blood and are crucial in research with minute quantities of substrate. These features become requirements in metabolism and toxicology research. The method involves replacement of the portal blood with a suspension of perfluorohydrocarbons to substitute for the major functions of natural blood. The total-continuous portal vein fistula makes it possible to investigate metabolic and transport phenomena in live animals which previously could be explored only by in vitro methods. The method may be applied to conscious animals with further refinements.     

Similarity between Copper Resistance Genes from Pseudomonas syringae pv. actinidiae and P. syringae pv. tomato

Twenty-eight strains of Pseudomonas syringae pv. actinidiae isolated in 1984, 1987 and 1988 from kiwifruit orchards in Japan were tested for their resistance to copper sulfate. All strains isolated in 1984 were copper sensitive with a minimum inhibitory concentration (MIC) of cupric sulfate of 0.75 mM. However, some strains isolated in 1987 and 1988 were resistant, with the MIC ranging from 2.25 to 3.0 mM. All copper-resistant strains contained at least one of two plasmids, pPaCul (about 70.5 kb) or pPaCu2 (about 280 kb), or both. In a copper-resistant strain Pa429, the location of the copper-resistance gene(s) was examined by insertional inactivation with Tn5. The MIC of copper sulfate in the copper-sensitive mutant obtained by Tn5 tagging decreased from 2.75 to 0.75 mM. The 14.5 kb BamHI fragment, designated pPaCuB14, containing the same locus mutagenized with Tn5 was cloned from pPaCu1. However, pPaCuB14 did not confer copper resistance in the transformant of copper-sensitive strain Pa21R, suggesting that this clone did not contain a full set of copper-resistance gene(s). Then a cosmid library of pPaCu1 was constructed and six cosmid clones hybridized with pPaCuB14 were selected. One of the six cosmids, designated pPaCuC1, conferred a near wild-type level of copper resistance in the transformant of the copper-sensitive strain. pPaCuC1 had a homologous region that hybridized with all of the PCR-amplifled fragments of copA, copB, copR, and copS genes of P. syringae pv. tomato. DNA sequence analysis of the homologous region revealed the existence of four open reading frames (ORF A, B, R and S) oriented in the same direction. The predicted amino acid sequences of ORF A, B, R and S had 80, 70, 97 and 95% identity with CopA, B, R and S of P. syringae pv. tomato, respectively. Received 5 July 2001/ Accepted in revised form 27 September 2001     

短毛柽柳(Tamarix karelinii Bge)的分类学地位探讨

短毛柽柳的分类学地位一直是柽柳属中争论的焦点之一。由于所持划分依据不同 ,认为短毛柽柳为刚毛柽柳杂种、变种或一独立的种。本文系统回顾了短毛柽柳的研究历史 ,对前人所做的有关刚毛柽柳和短毛柽柳形态学、解剖学、孢粉学、植物化学及分子生物学的研究结果进行了分析 ,并查阅了大量的标本 ,认为短毛柽柳是刚毛柽柳的一个变种 ,是从刚毛柽柳进化到另一个极端种的中间过渡阶段 ,同意Baum的意见 ,将其学名恢复为Tamarixhispidavarkarelinii (Bge)Baum .。     

Intestinal uptake,metabolism, and transport of naphthol: In vitro capacity,requirements, and inhibition

The metabolism and transport of [¹⁴C]-naphthol were investigated in sacs of rat small intestine to better understand metabolism of the pesticide carbaryl (which contains naphthol) in the intestine. The capacity to synthesize polar ¹⁴C-labeled metabolites was approximately saturated at 50 μM naphthol. The metabolic capacity of the cranial small intestine was about two times the capacity of the caudal. Anaerobic incubation severely suppressed naphthol metabolism. Sodiumfree medium suppressed metabolism only slightly but altered transport of water and of the polar ¹⁴C-labeled metabolites to serosal and mucosal fluids; the effect on metabolite transport cannot be explained by the effects of sodium on water movements, however. Calcium-free medium did not affect metabolism or metabolite transport; 2,4-dinitrophenol, and possibly phlorizin, but not ouabain, suppressed naphthol metabolism in specific regions of the intestine. Each of the three inhibitors altered metabolite transport. It is concluded that the capacity to conjugate naphthol in the small intestine is greater in the cranial than caudal regions; the quantity of naphthol taken up from the medium is proportional to the rate of formation of the polar metabolite, naphthyl glucuronide; addition of 2,4-dinitrophenol, phlorizin, or ouabain, or deletion of sodium, perturbed the transport of the polar metabolite, but the perturbance could not be explained by the effect on rate or direction of fluid transfer and indicated an effect on cellular permeability or on transport mechanisms; the effect of the three inhibitors and possibly of elevated naphthol concentrations (to 520 μM) in the medium on metabolite transport may be by a sodium interaction; the latter suggests that naphthol may be toxic to the intestine at concentrations approaching 100 to 1000 μM.     

割草对典型草原植物营养元素贮量及分配的影响 Ⅱ.地上生物量的营养元素贮量及分配

本文研究了内蒙古典型草原地区割草地 ９ 种营养元素的贮量及分配。研究结果表明：刈割对羊草、洽草、其它草种和群落的营养元素贮量产生了一定影响,其贮量有随刈割时间而逐渐增加的趋势。一年内,营养元素的高值期在 ８ 月 ３０日前后。割草区的贮量一般低于对照区,羊草的留茬部分低于割取部分的贮量,洽草则相反。在生物量高峰期 ８ 月 ３０ 日前后,其割草区群落的营养元素贮量为： Ｎ ３． ３５５７ｇ．ｍ － ２, Ｐ ０． １７４７ｇ． ｍ － ２, Ｋ ２．６２０３ｇ． ｍ － ２, Ｃａ １． ０７９５ｇ． ｍ － ２, Ｍ ｇ ０．１２７８ｇ．ｍ － ２, Ｆｅ ０． ０３２４ｇ．ｍ － ２, Ｃｕ １６６９． ６６μｇ． ｍ － ２, Ｍｎ １０３４３． ８４μｇ． ｍ － ２, Ｚｎ３３０３．５１μｇ．ｍ － ２。除 Ｍｎ 外,其它元素都是对照区高于割草区。上述 ９ 种营养元素贮量在割取部分中亦随刈割时间而逐渐增加,高峰期也在 ８ 月 ３０ 日前后,但留茬部分相反。割草区营养元素的贮量多数低于对照区,割取部分多数高于留茬部分。在生物量高峰期 ８ 月 ３０ 日前后,割草区群落的营养元素贮量分配在割取部分的为： Ｎ ６０．８４％ , Ｐ ４９．０６％ , Ｋ ５３．３４％ , Ｃａ ５９     

我国昆虫寄生线虫研究进展

在生物进化史上,线虫和昆虫在古生代(距今5-6亿年)就先后出现,在漫长的演化过程中,二者中有一部份发生了寄生与被寄生的关系。据聂克尔(Nickle,1974)记述,从欧洲莱茵河始新世(距今3700-6000万年)的煤炭和波罗的海琥珀中,发现两种寄生于昆虫的线虫(Heydonius antiquus和H.matutinus)化石,证明线虫寄生于昆虫已有很长历史。彭世奖考据(1983)江苏《高邮州志》记载:“庆元一年(1196年)飞蝗抱草死,每一蝗有一蛆,食其脑”,据认为是索科线虫害生所致。说明我国至少在十二世纪就有线虫寄生于昆虫的记录。而国外最早在十八世纪,Gould(1747)首次发表黄土蚁(Lasius flavus)被线虫寄生的情况。     

麦类作物对禾谷胞囊线虫的抗病性

于１９９５－１９９７年从广州南海市采集荸荠枯萎标本,经分离,纯化,鉴定和致病性测定,证实其病原为尖孢镰刀菌的荸荠专化型。寄主范围测定结果表明,被接种的１６种植物中仅有荸荠发病。该病菌分生孢子萌发的温度范围为８－３６℃。最适温度２８－３０℃。菌丝生长的温度范围为８－３４℃,最适温度２６－２８℃。