丁布的分离、纯化和结构鉴定及其对麦长管蚜

从玉米苗中分离、纯化得到丁布，利用纸层析，紫外分光光度扫描和核磁共振^1H NMR等技术对其作结构鉴定。结果与文献报道基本一致，且纯度在96.7%以上，以纯化的丁布为标样，用HPLC方法分析了不同抗性级别的小麦品种中丁布的含量。结果表明：品种之间丁布的含量差异显著，丁布的浓度与小麦的抗蚜级别呈显著负相关，与麦长管蚜的内禀增长率rm亦呈显著负相关，借助麦长管蚜全纯人工饲料研究表明，丁布对麦长管蚜有明显的拒食性作用。图3表2参13。     

莲缢管蚜对水葫芦生长的抑制作用

采用室外试验方法研究了不同密度和不同生育期的莲缢管蚜(Rhopalosiphumnymphaeae)对水葫芦(Eichhorniacrassipes)生长的影响.结果表明,莲缢管蚜成虫对水葫芦生长具有明显的抑制作用,表现在水葫芦植株鲜重减轻,总叶片数和新芽数减少,叶片枯萎数增加.低密度莲缢管蚜对水葫芦根和叶片生长的抑制作用不明显,但当莲缢管蚜密度大于20头·株-1时抑制效果显著,且随着作用时间的推移抑制作用更为明显.莲缢管蚜虽然对水葫芦生长具有一定的抑制作用,但由于其食性广泛,很可能会危及其他相邻水生植物,因此作为水葫芦天敌控制水葫芦生长的可行性还有待深入研究.     

污水灌溉区土壤肥力及酶活性特征研究

通过野外调查和采样分析,研究了石家庄栾城县不同污水灌溉时间（0-52a）和不同层位（0-100cm）耕地土壤肥力及酶活性的分布特征。研究结果表明：与清灌对照点相比,污水灌溉区表层（0-20cm）土壤有机质含量、全氮含量、全磷含量、蔗糖酶活性、脲酶活性和磷酸酶活性、亚表层（20-40cm）蔗糖酶活性、磷酸酶活性和下层（40-60cm）蔗糖酶活性均相对较高,而下层有机质含量、全氮含量和底层（60-100cm）全氮含量均相对较低。4层土壤阳离子交换量和过氧化氢酶活性较对照点均无明显的变化规律。表层土壤全氮含量、蔗糖酶活性和磷酸酶活性、亚表层有机质含量、蔗糖酶活性和磷酸酶活性、下层蔗糖酶活性与污灌时间之间均存在显著相关性沪〈0．05）。上述特征反映了土壤肥力及酶活性对污灌的响应具有明显的层位效应和非同步性,而这些响应是由于污水中的营养物质输入土壤后引发微生物活性提高的“激发效应”所致。     

上海大气PM_(2.5)中水溶性氨基酸的浓度及组成特征

氨基酸是大气颗粒物中一类重要的极性有机物,一定程度上可以反映生物气溶胶的贡献,也是大气氮沉降的重要部分,目前人们对大气细颗粒物中氨基酸的浓度和组成了解还很少。为了解上海大气细颗粒物中水溶性氨基酸的分布特征,利用大流量采样器采集了不同季节的PM_(2.5)样品,采用邻苯二甲醛/N-乙酰-L-半胱氨酸柱前衍生高效液相色谱法,分析了水溶性氨基酸(游离态及结合态)的浓度和组成。上海PM_(2.5)中游离态氨基酸(FAA)的浓度为0.058—0.690 nmol·m~(-3),平均为0.287nmol·m~(-3),冬、春季浓度稍高,但季节变化不显著。结合态氨基酸(CAA)的浓度为0.200—10.911 nmol·m~(-3),平均1.731 nmol·m~(-3),春季最高,秋季次之,冬季最低。FAA浓度与SO42-、NH_4~+、水溶性有机氮等主要水溶性组分间均存在显著相关性,细颗粒物的吸附及大气扩散条件可能是影响FAA浓度的重要因素,而CAA浓度与其他水溶性组分间不存在显著相关性。游离态氨基酸的组成以甘氨酸为主(51.9%),丙氨酸次之(12.9%),丝氨酸(7.1%)、天冬氨酸(5.5%)、谷氨酸(5.1%)、酪氨酸(4.9%)和苯丙氨酸(4.8%)也有一定含量,而亮氨酸、异亮氨酸和缬氨酸的含量很低;结合态氨基酸的组成与游离态氨基酸有明显差别,单体分布更均匀,甘氨酸的含量最高(29.3%),丝氨酸(12.5%)、谷氨酸(12.2%)、丙氨酸(10.8%)和苯丙氨酸(9.7%)是主要的单体化合物,大气光化学转化可能是造成上海PM_(2.5)中游离态氨基酸和结合态氨基酸组成差异的重要原因。主成分分析结果表明,化石燃料燃烧、生物质燃烧并非上海PM_(2.5)中氨基酸的主要来源。该研究结果能为大气细颗粒物环境影响研究提供基础数据。     

苯并(a)芘对大弹涂鱼(Boleophthalmus pectinirostris)卵巢还原型谷胱甘肽含量的影响

分析了大弹涂鱼肌肉、鳃、肝脏、内脏 (不含肝脏 )以及卵巢等的GSH含量 ;并以GSH含量最高的卵巢为研究对象 ,在实验条件下 ,经 0 (CK) ,0 .0 5 ,0 .2和 0 .5mg/L等不同浓度的BaP暴露 7d ,分析其卵巢GSH含量变化的时间 -效应和剂量 -效应特征 ,结果显示 :0 .5mg/L浓度组的大弹涂鱼卵巢GSH含量迅速升高 ,暴露 12h即显著高于CK(P≤ 0 .0 5 ) ,但随暴露时间的延长 ,其GSH含量显著降低 ,7d的样品显著低于CK(P≤ 0 .0 5 ) ;在暴露 3d ,GSH水平与BaP浓度的剂量 -效应关系表现为正相关 ,而在 7d ,则呈负相关 ,这可能表明大弹涂鱼卵巢对BaP暴露由适应性反应到产生毒性效应的过程 .以上研究结果表明 ,卵巢GSH可对BaP暴露作出快速灵敏的反应 ,GSH水平有可能作为具氧化 -还原循环活性的污染物暴露的一种敏感的生物标记 .图 2表 2参 9     

内蒙阿拉善地区植物与土壤元素背景值特征及其相互关系

内蒙阿拉善地区植物、土壤的元素背景特征及其相互关系的研究结果表明：５３种植物的９种元素（Ｚｎ、Ｃｕ、Ｎｉ、Ｐｂ、Ｃｄ、Ｃｏ、Ｃｒ、Ｖ、Ｍｎ）背景含量有很大差异．不同生活型植物背景值也各异，总的规律为：Ｍｎ＞Ｚｎ＞Ｖ＞Ｃｕ＞Ｎｉ＞Ｃｒ＞Ｐｂ＞Ｃｏ＞Ｃｄ；同种植物的元素含量在不同群落中有明显差别，但都在同一个数量级．土壤９种元素的背景含量均以Ｍｎ含量最高，其次为Ｚｎ和Ｖ，Ｃｄ的含量最低；不同上类各剖面各种元素的垂直分布规律为底层或表层的元素含量高于中间各层．土壤元素背景值都高于植物背景值，前者一般为后者的２～２０倍．植物对元素的吸收系数以Ｃｄ最大，Ｃｒ最小．土壤元素含量与有机质含量的相关性因土类不同而异：沙土的有机质含量最低，只有Ｚｎ含量与有机质相关性显著；而盐土的有机质含量最高，有Ｃｏ、Ｃｄ、Ｍｎ、Ｎｉ、Ｃｒ、Ｚｎ６种元素含量与之显著相关．     

冬季降雪过程对城市大气气态汞污染的影响

2009年降雪和非降雪期间对北京西北城区的气态总汞浓度进行了连续采样,比较了降雪期间、非降雪期间的气态总汞浓度日变化过程;降雪期间气态总汞浓度的降低和恢复过程。结果表明,降雪和非降雪期间大气气态总汞浓度的日均值有显著差异,降雪期间气态总汞的平均浓度为5．64ng·m^-3,非降雪期间的平均浓度为7．43ng·m^-3,前者约为后者的70％。降雪后约7h气态总汞浓度恢复到降雪前水平。研究中分析了气象因素（气压、风速、阵风速度、气温和相对湿度）对于气态总汞浓度的影响,结果表明：降雪期间主要受到风速（r=-0．527）和阵风速度（r=-0．574）的影响;非降雪期间主要受到风速（r=-0．691）,阵风速度（r=-0．726）和相对湿度（r=0．692）的影响,并且相对湿度的影响与风速的影响相近。降雪和非降雪期间气态总汞的日变化有所差异：非降雪期间气态总汞浓度在午夜和清晨较高,日变化趋势与相对湿度一致;降雪期间气态总汞的日变化没有明显规律。     

农业有机废弃物蚯蚓堆制因素优化及堆制产物主要性状变化特征

采用模拟培养法,对农业有机废弃物的蚯蚓堆制条件进行因素优化,并以优化后条件组合作为培养条件,进一步研究了蚯蚓堆制物性状的变化.结果表明,随蚯蚓处理时间增加,堆制物pH和C/N比值均显著降低,电导率却显著增加;速效N、P含量均在处理45天时达到最高,速效K含量在处理30天时达到最高;在堆制前期,蔗糖酶、脲酶及过氧化氢酶活性均增强,而磷酸酶活性则呈下降趋势.在蚯蚓堆制60天时,与猪粪+稻草混合堆制物[m(猪粪):m(稻草)=7:3,温度15℃,湿度75%,接种密度10尾·盆-1]的特性相比,猪粪+木屑混合堆制物[m(猪粪):m(木屑)=7:3,温度20℃,湿度75%,接种密度15尾·盆-1]的pH、电导率及速效K含量相对较低,而蔗糖酶、磷酸酶活性均相对较高.相对而言,利用蚯蚓对猪粪和木屑进行混合堆制可同时达到安全和资源化利用的目的.     

耐盐(CaCl2)皂素废水降解菌的分离及特性

从湖北省某皂素生产废水池底污泥中分离出2株耐高盐（CaCl2）皂素废水降解菌，编号分别为B723—1和B723—3，并进行菌株的鉴定和生长特性以及不同盐度迫胁下胞内游离氨基酸、蛋白质、膜的相对透性的研究，结果发现：（1）菌株B723—1与扩展短杆菌的同源性为98．0％～99．0％，B723—3与松鼠葡萄球菌的同源性为98．0％～99．0％：（2）两菌株均能在0．0％～9．0％CaCl2范围内生长良好；（3）菌株B723—1和B723—3的适宜生长温度分别是20～35oC和25～37oC，两者均在pH7．0～10．0生长；（4）当耐盐菌株受到1．8％、3．6％、5．4％和9．0％CaCl2盐迫45min时，其胞内会迅速积累大量氨基酸来平衡外界的高盐渗透压，且其胞内蛋白质含量均高于对照组（未受盐迫），而其膜的相对通透性低于非耐盐菌株．图4表1参11.     

太湖水-沉积物界面磷、pH及碱性磷酸酶的时空特征及相关性

于2011年3、6和9月通过对太湖不同营养化湖区的5个标准采样位点进行采样分析,探讨了界面沉积物间隙水和上覆水中磷含量、pH及碱性磷酸酶活性的时空分布特征及相关性。结果表明,上覆水及沉积物间隙水中的总磷（TP）、可溶性正磷酸盐（SAP）、pH及碱性磷酸酶（ALP）活性均表现出明显的空间异质性和季节变化趋势。间隙水总磷（PW-TP）、间隙水可溶性正磷酸盐（PW-SAP）高于上覆水,分别最高高出0．082、0．042mg·L-1;上覆水pH值高于间隙水pH值,最高高出O．35个单位;间隙水中碱性磷酸酶（PW-ALP）活性高于上覆水中碱性磷酸酶（W-ALP）活性,最高高出13．244μg·mL·h-1。TP、SAP、pH及ALP活性在3、6、9月份中均以16#样品最高,其中6月份16#样品PW-TP、PW-SAP、上覆水pH及PW-ALP活性分别O．527、0．132、7．46和61．090μg·mL·h-1。参数相关性分析结果表明,W-TP与W-SAP、W-pH显著相关。W-SAP与PW-TP、PW-SAP、W-ALP、PW-ALP均显著相关。PW-TP与PW-pH显著相关性,与PW-ALP活性存在一定的相关性,但不显著。PW-SAP与PW-ALP显著相关。     

Development and characterization of complex particles for delivery of amino acids to early marine fish larvae

Complex particles (CP), zein microbound particles and lipid-spray beads (LSB) were prepared and their performances were compared for delivering glycine and a mixture of free amino acids (FAA; alanine, glycine, leucine, serine and tyrosine) to early fish larvae. Measures of performances of microparticles included inclusion, encapsulation, retention and delivery efficiencies in addition to T50 (time to 50% retention) values. CP were prepared containing LSB and a defined dietary mixture that were bound together with zein. CP had significantly higher retention and delivery efficiencies for FAA compared to those of zein microbound particles. Free LSB had higher retention efficiencies for particulate glycine compared with CP, possibly due to differences in suspension characteristics. Free LSB clumped and floated when suspended in water, negatively affecting their acceptability by fish larvae; therefore, LSB should be incorporated into CP for more effective delivery of amino acids. There was a significant inverse correlation between retention efficiencies and solubilities of FAA encapsulated in CP. After 1 h of aqueous suspension, highest retention (44%) and delivery efficiencies (20.3 mg tyrosine g^–1 particle) were achieved with tyrosine. T50 values indicated 50% of the initial tyrosine in CP was still available after 36.7 min of suspension in water. Furthermore, CP can deliver FAA to marine fish larvae based on the results of feeding studies in which CP were digested by 3-day-old clownfish larvae; therefore, this particle type could be a valuable tool in studies of larval fish nutrition.Communicated by R.J. Thompson, St. Johns     

Analyzing maps of dispersal around a single focus

The spatial pattern of organisms may be used to characterize their dispersal, quantify spread or estimate the point of introduction of an alien species. Their distribution may be represented by maps of individuals, or by counts or by presence/absence at known positions within a sampled area. The problems and relative merits of these different forms of data for spatial inference are discussed. Three datasets concerning dispersal from a single focus are analyzed: counts of aphids, Rhopalosiphum padi and Sitobion avenae, on barley plants, Hordeum vulgare, grown in experi- mental trays; mapped locations of couch grass, Elymus repens, tillers within plots of a field experiment; locations of sightings of the lupin aphid, Macrosiphum albifrons, as it invaded Great Britain between 1981 and 1984. A method for generating maps from counts is proposed to overcome problems caused by recording imprecision. Several statistics are used to quantify dispersal and spatial pattern in the experimental data and together provide a clear picture of the spatial pattern observed; they enabled several effects of the experimental treatments to be identified. The value of the statistics are compared. Estimates of the source of the lupin aphid invasion are obtained using the backtracking methods of Perry (1995b) and do not contradict previous suggestions.     

Larval behavior of predacious sister-species: orientation,molting site,and survival in Chrysopa

Field and laboratory studies compared two features of larval behavior in a pair of predacious sisterspecies of green lacewings: one (Chrysopa slossonae) a specialist on a single species of colonial aphids (the woolly alder aphid) that occur on branches and trunks of alder trees, the other (C. quadripunctata) a general aphid feeder whose primary prey is dispersed on foliage of diverse types of trees. First, a few hours after hatching, larvae of the two species develop significantly different phototactic responses; the differences correspond well with the spatial distributions of their prey. Most C. slossonae exhibited negative phototaxis, a response that helps move hatchlings inward on alder trees toward the woolly alder aphid colonies, whereas most C. quadripunctata hatchlings showed positive orientation to light, a response that tends to keep them in tree canopies with their prey. Second, in greenhouse experiments, a significantly greater proportion of C. slossonae larvae (second instars) molted within woolly alder aphid colonies and remained with the aphids than did C. quadripunctata larvae. These differences indicate that the specialist larvae have evolved a high degree of behavioral fidelity to their prey. However, larvae (second instars) of the two species that were released near ant-tended woolly alder aphid colonies in the field had similar recovery (= survival) rates. Consequently, natural selection may not act on behavioral traits that influence larval fidelity to prey during the late second and early third instars.     

Tracing individual movements of aphids reveals preferential routes of population transfers in agroecosystems.

Agricultural pests are not restricted to crops, but often simultaneously or successively use different cultivated and uncultivated hosts. Nevertheless, the source-sink role of cultivated and uncultivated habitats in the life cycle of crop pests remains poorly understood. This is largely due to the difficulty of tracking displacements of small organisms in agricultural landscapes. We used stable-isotope ratios in order to infer the natal host plant of individuals of the English grain aphid Sitobion avenae colonizing wheat fields in autumn. We showed that among the numerous plant sources of S. avenae, maize, which has been intensively grown in western France since the 1960s, provided most aphids that attack wheat fields early in autumn. This study illustrates how insect pests respond to land-use changes within a relatively short period of time, rapidly acquiring a new host that in turn affected their population biology considerably by playing a pivotal role on their annual life cycle.     

Amino acid uptake and respiration by marine heterotrophs

The concentration and turnover of dissolved free amino acids were measured in samples from 25 and 100 m on three occasions at a station 6 miles off the California (USA) coast. Individual amino acid concentrations varied from undetectable (<0.05 g/l) to 3 g/l, the total amino acid concentration from 1.8 to 8.5 g/l. The greater concentration of total amino acids was always found at 25 m. The predominant amino acids were serine, lysine, aspartate, glutamate and alanine; reliable analyses could not be made for glycine because of a high blank. For the 10 individual amino acids studied, the rate of heterotrophic turnover ranged from undetectable to 1.2 g/l day^-1; serine, aspartate, alanine and glutamate showed the highest rates. In samples from 25 m, the rates were 15 to 20 times higher than those taken from 100 m. The total calculated flux of the amino acids studied varied from 0.015 to 3.2 g/l day^-1 and amounted to 1–10% of photosynthetic carbon dioxide fixation.     

Chemical defence in chewing and sucking insect herbivores: Plant-derived cardenolides in the monarch butterfly and oleander aphid

Summary Cardenolide sequestration by a hemimetabolous aphid and a holometabolous butterfly from the neotropical milkweed,Asclepias curassavica L., is compared. The oleander aphid,Aphis nerii B. de F., sequestered a similarly narrow range of cardenolide concentrations to the monarch butterfly,Danaus plexippus (L.), from the wide range of concentrations available in leaves of A.curassavica. However, A.nerii sequestered significantly less cardenolide (269 µg/0.1 g) thanD. plexippus (528 µg/0.1 g). The honeydew excreted by A.nerii was comprised of 46% cardenolide. The complete polarity range of 25 cardenolides detected by thin layer chromatography in A.curassavica was represented in the 17 whole aphid cardenolides and the 20 aphid honeydew cardenolides detected. D.plexippus sequestered a narrower polarity range of 11 cardenolides, having eliminated low polarity cardenolide genins and glycosides. It is suggested that these chemical differences may be related to interactions among the broad feeding tactics of sucking or chewing milkweed leaves, life history constraints of holometabolyversus hemimetaboly, the distribution of milkweed food resources in space and time, and the dynamics of natural enemies.     

Nutritional quality of phloem sap in relation to host plant-alternation in the bird cherry-oat aphid

Summary. Host alternation in aphids has been attributed to complementary growth of host plants, or more specifically to seasonal changes in the nitrogen quality of the phloem sap. In this report, seasonal fluctuation of free amino acids in phloem of the winter and summer host plants (Prunus padus, bird cherry and Hordeum vulgare, barley) of Rhopalosiphum padi (the bird cherry-oat aphid) were investigated in the context of aphid growth and behaviour. Phloem was collected from the cut stylets of aphids taken from plants that were grown outdoors. The total concentration of amino acids in P. padus phloem increased between bud break and late flush (spring), decreased in mature leaves (summer), and increased again in early senescent leaves (autumn). In H. vulgare, however, amino acid concentration fluctuated less from seedlings to flowering. Spring aphids from P. padus grew rapidly on this host from bud break to late flush, but died on mature and early senescent leaves. Summer aphids from H. vulgare grew as fast on this host as spring aphids did on flush leaves of P. padus. Sexual females grew more slowly than other generations and nearly as well on mature as on early senescent P. padus leaves. As judged by aphid growth and phloem nitrogen quality, P. padus during spring equals the summer host H. vulgare. However, the lower growth rates of R. padi on mature and senescent leaves of P. padus appear only loosely correlated with phloem amino acid concentrations. Therefore, factors influencing aphid nutrition, or ecology, other than seasonal changes in phloem sap amino acid concentration may explain the existence of host alternation in R. padi.     

天龙山珍稀植物丽豆(Calophaca sinica)分布区植物群落物种多样性与土壤因子的关系

采用样方法对太原天龙山珍稀濒危植物丽豆(Calophaca sinica)野生种群的生境和群落特征进行调查,应用TWINSPAN分类分析群落多样性.据TWINSPAN分类,将丽豆分布区的植物群落划分为14个群丛类型,丽豆在群落中具有明显的生态优势,并对群落的结构起一定决定作用.研究结果表明,丽豆分布区植物群落的物种多样性指数变化受自然环境、群落特征和人为干扰的综合影响,光照充足、人为干扰小的群丛类型的物种多样性较为丰富,在以丽豆为建群种或优势种的群丛中多样性指数较高,均匀度指数也较大.在丽豆分布区的9个土壤因子之间有6对因子存在显著和极显著的相关性;多样性指数与土壤因子回归分析表明,锌(Zn)与8个群落物种多样性指数之间有显著或极显著的相关性,钾(K)、磷(P)与6个多样性指数之间显著相关,其他土壤因子与多样性指数的相关性均不显著.     

中国两性生殖卤虫形态特征的数值分类研究

对中国两性生殖卤虫１２个品系的１０个品系形态特征进行了聚类分析和主成分分析，并与Ａ．ｕｒｍｉａｎａ进行了比较研究．研究结果表明，Ａ．ｕｒｍｉａｎａ和中国两性生殖卤虫各品系明显可分为２个类群，证明中国各两性生殖卤虫品系均属于Ａ．ｓｉｎｉｃａ．而Ａ．ｓｉｎｉｃａ不属于Ａ．ｕｒｍｉａｎａ．在中国两性生殖卤虫各品系中ＮＬ、ＨＪＱ、ＳＢ可分为另一类群，显示可能存在种下分类阶元．本文所选取的形态特征是稳定的，可做为卤虫品系形态特征数值分类的重要依据．     

Kinetics of osmoregulation in the crab Carcinus maenas

When shore crabs Carcinus maenas are transferred from 11 to 38 S at 11°C, new constant levels of hemolymph freezing points and of concentrations of Na, K, Ca, and Mg in the hemolymph are accomplished within 24h. From a decrease in serum protein and in serum free amino acids and an increase in the relative amounts of individual essential free amino acids in the body fluids of whole crabs, a participation of proteolytic activities and a transport of amino acids from hemolymph to cell is deduced; the stationary concentration of total intracellular free amino acids increases up to a nearly two-fold value, compared with the concentration in crabs remaining in diluted sea water. Also, the low molecular neutral sugars increase in whole crabs after high salinity stress, reaching values of more than two-fold initial concentrations within a period of 10 days. This increase is fully accounted for by a 6.7-fold increase in trehalose levels. The processes of increasing the concentrations of low molecular organic material seem to be slower than those of establishing new osmotic pressures in the hemolymph. The oxygen consumption decreases by 30 to 45% to new constant values within 8 to 12 h after the salinity change from 11 to 38, reflecting similar kinetics as the establishment of new osmotic pressures in the hemolymph.