干旱区绿洲土壤中Cd、Pb、Zn、Ni复合污染对芹菜的影响及其富集迁移规律

通过盆栽试验和室内分析初步研究了干旱区绿洲土壤中Cd、Pb、Zn、Ni复合污染对芹菜生长的影响及重金属在芹菜体内的富集迁移规律。结果表明:随着外源重金属添加量的增加,芹菜的生长受到明显抑制。根据多元回归分析和偏相关分析,芹菜地上部和根部吸收Pb量分别与外源添加Pb、Zn、Ni量和Cd、Pb、Zn、Ni量达到极显著相关,其中土壤Zn含量的增加极显著的降低了芹菜地上部和根部对Pb的吸收。芹菜地上部及根部对Cd、Pb、Zn、Ni四种元素的富集系数大小顺序均为:Cd>Zn>Ni>Pb,且根部对四种重金属元素的富集能力显著大于地上部。Cd在芹菜中的平均迁移能力最强,Zn、Ni次之,Pb的迁移能力最弱。     

干旱区绿洲土壤外源Cd、Pb的形态分布及再分配

以干旱区绿洲土壤为研究对象,采用Tessier连续提取技术对外源Cd和Pb的形态分布与再分配进行了研究。结果表明:在盆栽试验完成后,Cd和Pb主要以碳酸盐结合态和铁锰氧化态存在。Cd的全量是影响其可交换态、碳酸盐结合态和铁锰氧化态含量的主要因素,而有机物结合态和残渣态受其它因素的影响也较大。Pb的全量是其各种形态含量的主要影响因素。随着Cd和Pb添加量的增加,其土壤总的再分配系数呈增加趋势,结合强度系数则相反,表明Cd和Pb各形态间的稳定性下降。随着时间的推移,二者各形态会继续发生变化,但这一过程缓慢。因此,土壤重金属污染具有长期性。     

绿洲油菜根际土壤中Cd,Pb赋存形态特征及其互作影响

采用盆栽试验,设计了Cd、Pb以及Cd/Pb复合胁迫三种污染情景模式种植油菜,利用Tessier连续提取法对绿洲油菜地土壤重金属元素的形态含量及比例特征进行了分析。结果表明:干旱区绿洲油菜地原状土壤中Cd和Pb分别主要以铁锰氧化物结合态及残渣态形式存在,而添加可溶性Cd和Pb后,两金属的主要赋存形态均为碳酸盐结合态。在任何浓度添加水平,可交换态Cd,Pb对外界浓度胁迫响应最大,残渣态响应最小。三种污染情景模式下油菜根际土壤中Cd,Pb形态拟合方程及生物活性系数的对比分析表明:两金属的互作对各元素活性的影响为:Pb的加入抑制Cd的土壤活性,而Cd的共存则促进Pb的土壤活性。     

干旱区绿洲土壤Cd-Zn复合污染下重金属形态及其生物有效性的研究

通过模拟基于Cd-Zn复合污染下干旱区绿洲土壤的胡萝卜盆栽试验,用Tessier连续提取法对胡萝卜土壤中Cd、Zn的形态分布进行分析,同时就生物利用性形态的变化研究了Cd、Zn的生物有效性。结果表明:1)原状土壤中Cd和Zn主要以残渣态存在,随着复合胁迫浓度的增加,Cd的主要赋存形态逐步转变为碳酸盐结合态和可交换态,Zn主要赋存形态逐步转变为以铁锰氧化态和残渣态,但有效态和潜在有效态的比例大大增加。2)胡萝卜对Cd、Zn的富集作用均为地上部分大于地下部分,对Cd的富集能力远远大于Zn。3)胡萝卜吸收的Cd和Zn不仅包括可交换态和碳酸盐结合态,还包括了在一定条件下释放出来的铁锰氧化态和有机结合态。     

金昌城郊耕作土壤重金属Cu、Zn、Ni的分布规律

以干旱区绿洲金昌城郊耕作土壤为供试土壤,采用全量分析法和Tessier五步连续提取法研究了六个典型土壤剖面重金属Cu、Zn和Ni的总量以及形态纵向分布规律。结果表明:重金属Cu和Ni表聚现象明显,表层至下,其浓度先减少后稳定,两种元素在剖面中的迁移距离相近,基本在45cm附近;Cu和Ni化学行为相似,反映了Cu和Ni来源相同;Zn的总量分布没有明显的规律性。在土壤剖面中,Cu、Ni有形态变化层位,0-45cm有机态Cu>残渣态Cu>铁-锰氧化态Cu,碳酸盐态Cu>可交换态Cu;Ni的铁-锰氧化态>有机态,残渣态,碳酸盐态>可交换态;45cm后Cu、Ni主要以残渣态存在;Zn在所有土层中均以残渣态为主要赋存形态。研究土壤Cu、Ni的总量及形态分布主要受人为活动影响,Zn主要受成土母岩影响。     

干旱区绿洲土壤镉-锌-铅复合污染物在芹菜中的富集迁移规律

以干旱区绿洲土壤为供试土壤,采用盆栽实验研究了镉-锌-铅复合污染物在土壤/芹菜系统中的迁移富集特征.结果表明:随着外源添加重金属量的增大,芹菜根和叶中重金属含量也增大;芹菜根对Cd、Pb、Zn吸收量与土壤中Cd、Pb、Zn含量、外源添加Cd、Pb、Zn量之间都达到极显著正相关,芹菜叶对Cd 、Zn的吸收量与土壤中Cd、Zn含量、外源添加Cd、Zn量之间都达到极显著正相关;多元线形回归分析可知,芹菜根吸收Cd、Pb、Zn并没有受到共存元素的影响;重金属元素从土壤中分别向芹菜根/叶的富集能力顺序都为Cd＞Zn＞Pb,重金属元素在芹菜体内的迁移能力顺序为Zn＞Cd＞Pb.     

干旱区绿洲土壤Cd、Zn、Ni复合污染对芹菜生长及重金属积累的影响

以干旱区绿洲土为供试土壤,用芹菜(Apium graveolens)做指示植物,通过模拟盆栽试验,研究了土壤Cd、Zn、Ni复合污染对芹菜生长及重金属吸收积累的影响.结果表明:(1)低浓度的Cd、Zn、Ni重金属复合处理在一定程度上可促进芹菜根、茎叶的生长,重金属复合作用增强时,即Cd、Zn、Ni浓度增大时,毒害作用逐...     

干旱区绿洲土壤中Ni在芹菜中的富集迁移

以干旱区绿洲土壤为供试土壤,采用盆栽试验研究外源Ni污染对芹菜生长的影响及在芹菜中的富集迁移。结果表明：外源Ni的添加在低质量分数下能够促进芹菜的生长,达到一定临界值后,则出现明显的毒害作用;随着土壤中Ni的添加质量分数的增加,芹菜体内的Ni含量也随之增加。统计分析表明对芹菜根部和地上部吸收累积Ni贡献最大的均为铁锰氧...     

新乡小冀工业区周边土壤重金属污染评价与形态分析

通过实地调查和实验分析,对小冀工业区周边土壤中六种重金属(Cd、Cr、Cu、Ni、Pb和Zn)进行了总量测定。参照GB15618-1995二级标准,采用单因子指数法和内梅罗综合污染指数法对土壤质量进行了现状评价,并采用Tessier五步连续萃取法对超标重金属Cd、Ni和Zn进行了形态分析及生物活性分析。结果表明:1)Cr、Cu和Pb含量均未超过国标二级标准,Cd、Ni和Zn三种重金属含量均超标,工业区综合污染非常严重,主要污染元素是Cd;2)Cd、Ni和Zn在土壤中的形态分布差异性较大,Cd主要以铁锰氧化物结合态存在,Ni和Zn主要以残渣态和铁锰氧化物结合态存在;3)金属生物活性系数大小顺序为Cd>Zn>Ni,迁移系数的大小顺序是Cd>Zn>Ni,其中Cd的生态风险很大。     

宝鸡某冶炼厂周边土壤铅镉总量及形态空间分布特征

采用克里金插值法对宝鸡某冶炼厂周边农田土壤中铅镉含量及形态空间分布特征进行了研究,并分析了土壤中铅镉总量及各形态含量与小麦中铅镉含量的相关性,目的在于为冶炼厂周边土壤重金属污染的表征提供依据。结果表明,土壤中Pb形态的高低顺序为：残渣态>有机硫结合态>铁锰氧化态>可交换态,Cd形态为：可交换态>残渣态>有机硫结合态>铁锰氧化态。土壤中Pb总量及Pb、Cd铁锰氧化态在距离冶炼厂500 m处含量均显著高于1 500 m和2 500 m处,后两者之间无差异;而Cd总量及Pb、Cd可交换态、有机硫结合态和残渣态在三个采样距离并没有表现出显著性差异。克里金插值分析表明,除Pb可交换态外,Pb和Cd其余形态在一定程度上均显示出与风向的一致性。相关分析表明,土壤中Pb、Cd可交换态、铁锰氧化态与小麦Pb和Cd含量均有显著的相关性,表明冶炼厂周边旱地土壤中,Pb、Cd可交换态和铁锰氧化态都可能作为土壤重金属污染空间分布和有效性表征的指标。     

Pests,Predators, and Parasites

Abstract

The development of resistance to insecticides and the hazards inherent in their use present ever-increasing problems in insect control today. The difficulties and dangers have given impetus to research on other means of combating pests. Australia has always been prominent in the field of biological control, and the CSIRO Division of Entomology is an important centre, keenly seeking controls for both insects and weeds. Progress in the search for and establishment of parasites of Sirex, the pine pest, was described in Rural Research 64. This article reviews six other projects of particular interest, namely those involving potato moth, buffalo fly, white wax scale, green vegetable bug, lantana, and skeleton-weed.     

Mercury, arsenic, and cadmium in fish, water, and sediment of American Falls Reservoir, Idaho, 1974.

Mercury and cadmium were found in fish, water, and sediment of American Falls Reservoir (AFR), Idaho. Mercury and cadmium levels in some fish exceeded human health standards set by the Food and Drug Administration, U.S. Department of Health, Education and Welfare, and the World Health Organization. Analyses performed on the flesh of rainbow trout showed mercury residues of up to 1.20 mg/kg, which were higher than residues previously reported in trout collected in 1970 and 1971 from AFR. Cadmium residue levels were as high as 0.80 mg/kg. Although arsenic was found in reservoir sediment at levels of 1.36-2.40 mg/kg, it was not detected in fish.     

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.     

Species, Cultivars, Rootstocks and Environment

World apricot production by no means meets the total need of the international market (fresh and processed fruits) and is far below the potential in view of the existing favourable geographic, climatic and agrotechnical conditions. The cause for this insufficient world production of apricots, particularly in certain countries which have favourable conditions for apricot culture and its expansion, should be investigated using scientific and technical concepts concerning the apricot decline syndrome (apoplexy, sudden wilting, withering of apricots). After the mutual assistance of research workers from different disciplines in investigating this complex disease, the economic security of apricot growing can be improved and apricot decline reduced to an acceptable level. Special attention must be paid to selecting appropriate cultivars, rootstocks or interstocks, locations and cultivation techniques.     

Insecticidal activity of N,N-diethyl-, N,N-dipropyl-, N,n-di-isopropyl-, and n,n-di-isobutylalkanamides against mosquito larvae

N,N-Diethyl-, N,N-dipropyl-, N,N-di-isopropyl, and N,N-di-isobutylalkanamides in which the acyl moiety ranged from C₈ to C₂₁ were synthesised, and their larvicidal activity was determined against the first-instar larvae of the southern house mosquito Culex quinquefasciatus Say. The four homologous series of amides generally showed an increase in their larvicidal activity as the carbon number in the acyl moiety of the amides increased, until the activity reached a maximum. Subsequently, an increment of carbon number resulted in declining activity in the higher homologues, until the activity disappeared. N,N-Diethyltetradecanamide, N,N-dipropylundecanamide, N,N-di-isopropylundecanamide, and N,N-di-isobutlynonanamide or -dodecanamide were the most active compounds in their respective homologous series of amides; however, they were less active than their analogous N,N-dimethylalkanamides previously studied.     

Dieldrin residues in soybeans in Illinois, 1965, 1966, 1967, 1971, and 1974

The Illinois soybean crop was monitored in 1965, 1966, 1967, 1971, and 1974 for dieldrin residues resulting from aldrin applied to corn in the years before soybean cultivation. Residue levels of dieldrin in soybeans increased between 1965 and 1974. The percent of fields which had soybeans with a dieldrin level above 0.03 ppm increased between 1965 and 1974. Dieldrin residue levels in soybeans grown in Illinois are expected to decline now that the use of aldrin has diminished and will soon cease. No significant correlation was evident between the dieldrin levels in soybeans and the area of the State where they had grown, the date of planting, or the variety.     

施肥对小麦、玉米和大豆连作土壤微生物群落功能多样性的影响

为了明确长期施肥和不施肥条件下作物连作对土壤微生物群落功能多样性的影响,以典型黑土为研究对象,选取长期定位实验站长期施肥和不施肥条件下的小麦、玉米和大豆连作处理,通过稀释平板法和Biolog Eco微平板法,测定土壤细菌、真菌、放线菌数量、碳源代谢活性等指标,为建立合理的农田管理措施提供数据支撑和理论依据。结果表明:长期施肥条件下大豆、小麦和玉米连作土壤细菌、真菌和放线菌数量均高于不施肥处理,且均以大豆连作处理细菌和真菌数量最高。不施肥条件下小麦和玉米连作土壤细菌总数较大豆连作处理分别下降了24.8%和31.0%,真菌总数分别下降了64.0%和51.2%;施肥条件下小麦和玉米连作土壤细菌总数则较大豆连作处理分别下降了29.0%和45.5%,真菌总数分别下降了26.7%和31.5%。Biolog结果表明,不施肥条件下小麦连作处理的平均颜色变化率(AWCD)高于玉米和大豆连作处理,施肥条件下则是大豆连作处理的AWCD值高于小麦和玉米连作处理。不施肥条件下大豆、玉米和小麦连作处理利用最多的碳源是碳水化合物类,施肥后不同连作处理利用最多的是碳水化合物类和多聚物类。大豆和小麦连作不施肥条件下土壤微生物利用率最高的碳源均是α-D-乳糖,施肥条件下利用率最高的碳源均是D,L-α-甘油,而不论施肥与否,玉米连作条件下土壤微生物利用率最高的碳源均是D-半乳糖醛酸;葡萄糖-1-磷酸盐和γ-羟基丁酸是农田黑土微生物群落特异利用的关键碳源。主成分分析得出,施肥对土壤微生物碳源代谢能力的影响大于作物的影响。     

四种常用三唑类杀菌剂在香蕉上残留行为及使用评价研究

采用田间试验研究了戊唑醇、氟环唑、苯醚甲环唑、丙环唑等4种常用三唑类杀菌剂在香蕉上的残留行为, 并比较了戊唑醇在套袋与不套袋情况下的最终残留量。研究结果表明：香蕉上戊唑醇、氟环唑、苯醚甲环唑、丙环唑的降解半衰期分别为10.8~14.1、8.1~9.5、7.9~12.9、9.4~15.6 d。在试验剂量条件下, 末次施药后42 d时, 戊唑醇(不套袋)、戊唑醇(套袋)、氟环唑、苯醚甲环唑、丙环唑在蕉肉中的残留量分别为：0.01~0.04、<0.01、0.01~0.08、≤0.01 mg/kg和0.02~0.07 mg/kg; 在全蕉上的残留量分别为0.05~0.47、<0.01、0.10~0.36、0.03~0.19 mg/kg 和0.05~0.32 mg/kg。香蕉果肉占全果的比例约为55%~75 %, 全果的残留量约为果肉2~19倍, 表明香蕉中戊唑醇、氟环唑、苯醚甲环唑、丙环唑主要残存在果皮上。戊唑醇防治香蕉叶斑病, 在套袋情况下可以显著地减少其在收获期香蕉上的残留。