臭氧处理下转基因棉花凋落物分解对土壤跳虫的影响

【目的】转基因棉花已经在我国大量种植,未来气候变化下转基因作物分解与养分循环及作物产量密切相关,但是这种交互作用对凋落物分解及土壤动物的影响并不知道。【方法】本文通过野外凋落物分解实验,研究了臭氧升高和转基因品种处理下棉花凋落物分解对跳虫的影响。【结果】结果发现,无论是3次调查的总体分析还是在不同棉花生长期,不同棉花品种和臭氧浓度通过棉花凋落物对跳虫多度、类群丰富度和群落多样性指数均没有显著影响。但是有一些类群如棘跳和长跳在转基因棉花凋落物中显著减少,说明转基因棉花凋落物对跳虫某些类群存在一定影响,可能与转基因棉花凋落物中的高纤维素和木质素有关,因为这些可以影响跳虫的食物质量。【结论】转基因品种和臭氧升高对跳虫总体并未产生显著影响,但是对一些敏感类群产生了显著影响,未来还需要对这些敏感类群进行长期的监测以保证土壤生态系统中多样性和功能的安全性。     

城市化和绿地类型对土壤跳虫群落及功能性状的影响

随着城市规模不断扩大和城市植被管理实践的日益推进,我国城市化进程正在飞速发展。城市化进程的加快及其导致的植被改变强烈影响土壤生物多样性。作为城市绿地生态系统中的优势类群和环境变化的指示生物,土壤跳虫的群落结构和功能性状变化反映了环境变化对土壤生态功能的影响。以跳虫为研究对象,按照城市化梯度,分别在公园绿地、道路两侧绿化带、居民区绿地和工业园绿地四种绿地类型中采集样品,并选择森林样地作为对照,探讨了城市化和绿地类型对跳虫群落及其功能性状的影响。结果表明：(1)不同绿地类型中跳虫群落组成和结构存在显著差异,其中森林中等节跳科的丰度最高,而其它绿地中为长角跳科;城市化和绿地类型显著影响了跳虫的物种多样性,其中城市公园中跳虫的Shannon指数比城郊公园显著降低,而城市居民区中的Shannon指数显著高于城郊居民区;在城市生境中,居民区和绿化带中跳虫的Pielou均匀度指数显著大于公园,而在城郊中,公园中的物种丰富度和Shannon指数均显著大于森林。(2)相比城市化,绿地类型对跳虫功能性状的影响更强烈,比如公园、绿化带和居民区等人为扰动较强的绿地筛选出了弹器发达、相对腿长较长和体色较深的表土...     

转基因水稻Bt汕优63种植两年对土壤线虫群落的影响

通过连续2年的大田试验,对转基因水稻Bt汕优63(BtSY63)及其亲本汕优63(SY63)种植下大田土壤线虫数量、营养类群组成、生态指标和群落组成进行对比分析.结果表明:BtSY63和SY63种植下土壤线虫数量均随种植时间发生明显波动,但两者间无显著差异;与SY63相比,BtSY63种植下捕杂食线虫百分比和Shannon多样性指数出现了短暂的增加,但仅在个别时间差异显著;非度量多变量排序(nMDS)分析表明,BtSY63和SY63种植下土壤线虫群落组成无显著差异.可见,大田BtSY63种植2年对土壤线虫群落的影响不显著.     

转基因玉米对田间节肢动物群落多样性的影响

通过对转基因耐除草剂(EPSPS)抗虫(Cry1Ab)玉米转化体‘DBN9936’、受体玉米‘DBN318’、常规玉米‘先玉335’和喷施除草剂的转化体‘DBN9936’玉米田中节肢动物种类及数量的调查, 评价转基因玉米对田间节肢动物群落多样性的影响。2015年和2017年我们采用直接观察法、陷阱调查法和剖秆法对田间节肢动物进行调查, 采用聚类分析、物种累积曲线等方法对数据进行分析, 并比较了4个处理玉米田节肢动物群落的Margalef丰富度指数、Shannon-Wiener多样性指数、Simpson多样性指数、Pielou均匀度指数、优势集中性指数和群落相似性指数的差异及其随时间变化的规律。调查期间共记录节肢动物20目80科; 转化体玉米‘DBN9936’ (2015: 10.3 ± 2.6头, 2017: 3.3 ± 1.7头)和喷施除草剂的转化体玉米‘DBN9936’ (2015: 6.0 ± 1.5头, 2017: 17.0 ± 0.6头)上鳞翅目昆虫的数量明显低于受体‘DBN318’ (2015: 20.0 ± 3.2头, 2017: 24.0 ± 6.0头)和‘先玉335’ (2015: 21.0 ± 8.9头, 2017: 26.7 ± 2.0头); 物种累积曲线呈典型的抛物线, 各类玉米田间总体物种丰富度差异较小; 玉米生育期节肢动物调查结果累计数量的功能团组成及其丰富度、多样性、均匀度、优势集中性间均无明显的差异, 各类指数随时间变化的动态趋于一致, 群落间相似性程度较高。转基因玉米‘DBN9936’对鳞翅目害虫有明显的抗性, 对非靶标节肢动物无显著的影响, 对田间节肢动物的群落多样性、均匀度、丰富度、优势集中性等没有明显的影响。     

乌鲁木齐地区不同生境下土壤跳虫群落结构及多样性研究

为了解乌鲁木齐地区不同生境土壤跳虫群落结构及其多样性,研究土壤跳虫群落结构特征,了解不同生境差异对土壤跳虫群落结构的影响,分别在2008年4月、7月、9月和11月中旬对该区自然榆林、防护林、植物园、草地、居民点、废弃地及菜地等7种典型生境土壤跳虫群落特征进行了调查。共采集跳虫3728只,隶属于4目13科27属,其中伪亚跳属Pseudachorutes、球角跳属Hypogastrura、棘跳属Onychiurus、等节跳属Isotoma为优势类群,分别占总数的13.25%、12.31%、11.40%、10.03%,共占总数的47.00%。跳虫属Podura、长跳属Entomobrya、原等跳属Proisotoma、土跳属Tullbergia、驼跳属Cyphoderus、裸长角跳属Sinella、钩圆跳属Bourletiella、德跳属Desoria、小等节跳属Isotomiella、疣跳属Neanura、类符跳属Folsomina、符跳属Folsomia、刺驼跳属Cyphoderopsis及缺弹跳属Anuropho-rus等14属为常见类群,共占总数的47.65%,其余9属均为稀有类群,共占总数的5.35%。不同生境土壤跳虫的个体数和类群数差异较大(P<0.05),其中个体数顺序为自然榆林>防护林>草地>植物园>居民点>废弃地>菜地。跳虫个体密度和类群数在不同季节间差异明显(P<0.05),其中个体数顺序为9月>7月>4月>11月,Shan-non-Wiener多样性指数(H)在不同生境间均有显著差异(P<0.05),其顺序为植物园>防护林>自然榆林>草地>居民点>废弃地>菜地。Simpson优势度指数(C)为菜地>居民点>废弃地>草地>自然榆林>植物园>防护林。各生境间土壤跳虫群落的相似性较差,仅少数生境间相似性达到相似水平。研究表明不同生境植被类型是影响该区跳虫群落结构和多样性的主要因素。     

贵州省典型汞铊矿区周边农田土壤跳虫群落特征

大量的采矿活动导致矿区周边土壤重金属污染, 严重危害土壤生物安全。汞、铊等重金属元素毒性强, 相关污染的土壤生态风险鲜有研究。跳虫作为土壤环境变化指示生物, 能很好地反映土壤质量的健康状况。本研究以贵州省某汞铊矿区周边的农田土壤为研究对象, 按离矿区距离和作物类型设置4个采样区, 每个采样区种植2种作物, 每种作物农田设置3个样方。研究土壤跳虫群落结构和多样性及其影响因子。结果表明, 调查区内跳虫平均密度为12,000 ind./m²; 采样区距离矿区越近, 土壤重金属污染程度越大, 综合污染指数越高, 跳虫种数、密度、多样性和丰富度指数均呈先增加再降低的趋势; 环境因子分析表明重金属显著影响跳虫群落结构: Folsomides americanus、Isotomiella minor和Protaphorura encarpatus数量与汞、铊和砷含量呈负相关。高有机质含量能缓解重金属对土壤跳虫的影响, 但作物类型(玉米与薏仁)对土壤跳虫群落结构的影响无显著差异。本研究结果表明土壤有机质或能反向调节重金属污染对土壤跳虫群落的影响。     

长白山地典型农田生态系统土壤跳虫群落结构及其生态分布特征

为了解长白山地不同地貌类型典型农田生态系统土壤跳虫群落结构及其分布,探讨不同地貌类型对土壤跳虫群落结构和分布及其季节动态的影响,于2015年春季(5月)、夏季(7月)、秋季(9月)分别对长白山地玄武岩台地、花岗岩低山、花岗岩丘陵三种地貌类型玉米田土壤跳虫进行了研究。研究表明,3个生境共获土壤跳虫881头,隶属10科16属22种。其中,玄武岩台地土壤跳虫个体密度是1 760头/m~2,17种;花岗岩低山个体密度是2 206.67头/m~2,13种;花岗岩丘陵个体密度是1 906.67头/m~2,18种。地貌及取样时间的差异对土壤跳虫个体密度、物种数、多样性指数均有一定的影响。花岗岩低山与花岗岩丘陵的个体密度和物种数大小为秋季春季夏季,而玄武岩台地的个体密度和物种数表现出随季节变化呈递增的趋势(P0.05)。不同地貌土壤跳虫多样性均在秋季达到最大,夏季玄武岩台地多样性指数显著高于花岗岩低山和花岗岩丘陵,秋季,玄武岩台地丰富度指数和均匀度指数显著高于花岗岩低山,玄武岩台地优势度指数显著低于花岗岩低山(P0.05)。不同土壤环境因子对跳虫的影响不同,土壤温湿度、有机质、全氮、速效氮和全磷与土壤跳虫的群落结构、生态分布有明显的相关性。综上可知,长白山地农田生态系统土壤跳虫群落结构和生态分布因地貌类型不同而存在差异,季节变化也对其影响明显。     

种植黄连和重楼对小型土壤节肢动物群落的影响

为了掌握中药材种植对土壤动物群落的影响,于2020年7月对成都市彭州境内种植期为3年和5年的黄连和重楼样地的小型土壤节肢动物进行了调查.共分离到小型土壤节肢动物526只,隶属于4纲17目69科98类或属,优势类群为等节跳属、平懒甲螨属、符跳属和副跳属.小型土壤节肢动物群落组成结构在不同中药材样地间差异明显,影响群落组成...     

转植酸酶基因玉米种植对土壤线虫群落的影响

土壤是生态系统中物质循环和能量转化的重要场所,转基因作物外源基因对土壤非靶标生物的影响已经引起人们的广泛关注.我国转植酸酶基因玉米(即自交系BVLA430101)于2009年9月27日获得了生物安全证书,该转植酸酶基因玉米可提高饲料利用效率,减少动物粪便造成的环境污染.本文以转植酸酶基因玉米(简称转基因玉米)和常规对照亲本玉米(简称对照玉米)为试验材料,通过大田试验研究了转基因玉米和对照玉米种植对土壤线虫群落组成与生态指标的影响.结果表明： 转基因玉米和对照玉米大田土壤分别分离出29个属和26个属的线虫.与对照玉米相比,转基因玉米种植田食细菌线虫相对多度与数量、捕/杂食线虫数量和土壤线虫总数,以及群落多样性指数等都有升高的趋势,而植食线虫相对多度与线虫总成熟度指数呈降低趋势.重复测量方差分析表明,整个生长季节内转基因玉米与对照玉米田间不同营养类群土壤线虫相对多度与数量及生态指标均无显著差异;而T检验分析表明,玉米乳熟期转基因玉米田食细菌线虫、捕/杂食线虫数量和土壤线虫总数显著高于对照玉米田,这可能与乳熟期转基因玉米田土壤总氮含量显著升高有关.     

重金属铜对3种跳虫的影响

为选择适于国内土壤环境健康测试的跳虫物种,采用重金属食物投入法,比较分析了重金属铜对3种跳虫的影响,结果表明：3种跳虫中似少刺齿姚（Homidia similis）敏感性最强;小原等节姚（Proisotoma minuta）耐受性最强;紫女兆（Ceratophysella duplicispinosa）的敏感性和耐受性均位于二者之间。低浓度的铜能促进3种跳虫的生长和繁殖。与以往相关研究结果比较显示。小原等节虫兆较以前认为的最具耐受性物种——环带长角长姓（Orchesella cincta）有更好的耐受性．为研究跳虫耐受机制的一种好材料。而刺齿姚类则可能是土壤环境健康状况的敏感指示生物。     

Cry1F protein not detected in soil after three years of transgenic Bt corn (1507 corn) use

To evaluate the potential of Bacillus thuringiensis (Bt) Cry1F protein accumulation in soil, transgenic corn containing event DAS-01507-1 encoding the cry1F gene was grown in three field sites for 3 consecutive yr, and the corn plants were incorporated into the soil through postseason tillage or no tillage each year. Soil samples were collected from these fields, and the level of Cry1F protein in these samples was determined using an enzyme-linked immunosorbent assay (ELISA) with a synthetic invertebrate gut fluid as an extraction buffer. The ELISA was validated in soil matrices over the concentration range of 18-180 ng/g dry weight, with a limit of detection of 4.5 ng/g dry weight. The assay was shown to have good accuracy and precision. No detectable Cry1F protein was found in any of the soil samples collected from the Cry1F corn fields. Soil also was bioassayed, and no biological activity was observed against Heliothis virescens neonates. These results indicate that the level of Cry1F protein accumulated in soil after 3-yr continuous planting of transgenic Cry1F corn is negligible.     

Effect of Cry3Bb1-expressing transgenic corn on plant-to-plant movement by western corn rootworm larvae (Coleoptera: Chrysomelidae)

Dispersal of larvae of the western corn rootworm, Diabrotica virgifera virgifera LeConte, in specific combinations of transgenic corn expressing the Cry3Bb1 protein and nontransgenic, isoline corn was evaluated in a 2-yr field study. In total, 1,500 viable western corn rootworm eggs were infested in each subplot. Each year, plant damage and larval recovery were evaluated among four pedigree combinations (straight transgenic; straight nontransgenic corn; nontransgenic corn with a transgenic central, infested plant; and transgenic corn with a nontransgenic central, infested plant) on six sample dates between egg hatch and pupation. For each subplot, the infested plant, three successive plants down the row (P1, P2, and P3), the closest plant in the adjacent row of the plot, and a control plant were sampled. The number of western corn rootworm larvae recovered from transgenic rootworm-resistant plants adjacent to infested nontransgenic plants was low and not statistically significant in either 2001 or 2002. In 2001, significantly fewer larvae were recovered from transgenic rootworm-resistant plants than from nontransgenic plants when both were adjacent to infested, nontransgenic plants. In 2002, significantly more neonate western corn rootworm larvae were recovered from nontransgenic plants adjacent to infested, transgenic rootworm-resistant plants than nontransgenic plants adjacent to infested, nontransgenic plants on the second sample date. Together, these data imply that both neonate and later instar western corn rootworm larvae prefer nontransgenic roots to transgenic rootworm-resistant roots when a choice is possible. However, when damage to the infested, nontransgenic plant was high, western corn rootworm larvae apparently moved to neighboring transgenic rootworm-resistant plants and caused statistically significant, although only marginally economic, damage on the last sample date in 2001. Implications of these data toward resistance management plan are discussed.     

Effect of insulin and cortisol on oxidation of (1-14C)glucose, (6-14C)glucose, (1-14C)palmitate and (1-14C)leucine in the tissues of swine during the neonatal period

The intensity of [1-14C]glucose, [6-14C]glucose, [1-14C]palmitate and [1-14C]leucine oxidation and the effect of insulin and hydrocortisone on this process were studied in the brain, duodenum mucosa, liver and skeletal muscle of 1- and 5-day old piglets in vitro. Most of the studied substrates are oxidized in the tissues of 5-day piglets more intensively. Insulin stimulates oxidation of [1-14C]glucose, [6-14C]glucose and [1-14C]leucine in the brain and duodenum mucosa in 1- and 5-day old piglets, while in the liver and skeletal muscle--only in 5-day old piglets. Hydrocortisone administration enhances oxidation of [1-14C]leucine in most of the studied tissues in 1-day piglets and oxidation of [1-14C]glucose and [6-14C]glucose--in 5-day piglets. Both hormones produce no essential influence on the intensity of [1-14C]palmitate oxidation in the studied tissues of piglets or somewhat weaken it.     

Effect of extended diapause on evolution of resistance to transgenic Bacillus thuringiensis corn by northern corn rootworm (Coleoptera: Chrysomelidae)

We develop a population genetics model for the northern corn rootworm, Diabrotica barberi Smith & Lawrence, to examine the effect of extended diapause on the evolution of resistance to transgenic Bacillus thuringiensis (Bt) corn, Zea mays L. We model conditions found in the center of the extended diapause problem along the Minnesota-South Dakota-Iowa borders. The proportion of resistance alleles in eggs oviposited after 15 simulated years is used to measure the evolution of resistance. Sensitivity analysis indicates that although population genetics parameters (fecundity, initial egg density, density-dependent larval survival, random mating, insecticide mortality, and gene expression) affect the evolution of resistance, product characteristics (e.g., Bt toxin dose) and farmer management practices (e.g., insecticide use on refuge corn and rotation pattern) generally have a larger impact on the development of resistance. Exceptions to this generalization exist: 1) if the resistance allele is dominant, resistance evolves quickly; 2) the level of random mating is an important determinant of how quickly resistance evolves for a theoretical high dose product; and 3) small differences in insecticide mortality imply large differences in resistance for medium- and low-dose products with high levels of Bt corn adoption and a predominance of 1- and 2-yr corn rotations. When extended diapause spreads into a new area, it typically reduces resistance to Bt corn, assuming Bt corn is used only on continuous corn. In the study region where extended diapause already exists, increasing extended diapause (increasing hatch rates after two or three winters while holding total hatch constant), tends to increase resistance because the resistance increasing effect of the hatch rate after two winters dominates the resistance decreasing effect of the hatch rate after three winters. However, this is not always the case, because combinations of rotation pattern, toxin dose, and soil insecticide use exist for which the net effect of extended diapause decreases resistance. Results are interpreted as a combination of two offsetting effects. First, extended diapause injects older alleles with lower resistance allele frequencies into the breeding population, which slows resistance. Second, extended diapause speeds the population's recovery from perturbations (reduces the undercompensating density dependence of population dynamics), which accelerates resistance.     

玉米秸秆还田培肥土壤的效果

辽北地区玉米根茬还田、秸秆直接还田或间接还田的3年微区培肥试验研究结果表明,无机肥的增产效果特别明显,而施有机物料,更主要的作用是改善土壤的物理、化学性质、培肥地力,与无肥对照相比,有机无机肥料配合施用可使土壤有机质提高3．06％－27．78％,各有机物料对土壤有机质提高的顺序依次为100％秸秆＞50％秸秆＞土粪＞牛粪＞33％秸秆＞根茬。在含C量相等的条件下,秸秆对土壤有机质的保持和提高好于土粪,土粪好于牛粪。同时,与单施化肥比,有机无机肥料配合施用可使土壤易氧化有机质增加10．91％－20．67％,使浸提腐殖酸提高1．43％－14．28％,使结合态腐殖酸的松／紧比值提高0．07－0．19,HA／FA比值提高0．07－0．24,并且能改善土壤的N、P、K营养状况、土壤水分和土壤孔隙状况,这标志着土壤有机质活性的提高和土壤肥力状况的改善。因此,应该大力提倡玉米秸秆秋季直接还田,其最佳施入量应为当年生产量的30％－50％。     

转cry1C基因抗虫稻谷对黄粉虫生长发育的影响

【目的】研究转cry1C基因抗虫水稻(T1C-19)稻谷对黄粉虫生长发育的影响,为转Bt基因水稻的推广和应用提供理论支持。【方法】在试验室条件下,分别用100%T1C-19稻谷、100%明恢63(MH63)稻谷、62%T1C-19稻谷、62%MH63稻谷和正常饲料饲喂黄粉虫幼虫直至其化蛹,比较各处理组体重、存活率、幼虫历期、化蛹率和羽化率等检测指标。【结果】正常饲料组、62%T1C-19稻谷组和62%MH63稻谷组的黄粉虫幼虫体重几乎都显著高于100%T1C-19稻谷组和100%MH63稻谷组,但T1C-19和MH63组间差异不显著;此外,5组间的存活率、幼虫历期、化蛹率及羽化率差异均不显著。【结论】黄粉虫可通过取食转cry1C基因稻谷暴露于Cry1C蛋白中,但黄粉虫的生长发育没有受到明显的负面影响;转cry1C基因稻谷可作为饲料原料用于黄粉虫养殖。     

Effect of arbuscular mycorrhizal fungi on phytoextraction by corn (Zea mays) of lead-contaminated soil

The role of arbuscular mycorrhizal fungi (AMF) in lead (Pb) uptake by corn (Zea mays) grown in soil supplemented with Pb was examined. Plants were subjected to four Pb levels: 0 (control); 10 (low); 100 (medium); and 500 mg L(-1) (high). At each Pb level, plants were grown in soil without and with fungicide (benomyl) (20 mg kg(-1)) to suppress AMF activity. Benomyl significantly reduced AMF colonization at high. medium, and zero Pb exposures. Benomyl application resulted in significantly lower concentrations of phosphorus in leaves at low and medium Pb exposures. The benomyl-treated plants had higher Pb and manganese concentrations in leaves than plants not treated with benomyl. In addition, benomyl-treated plants had generally lower concentrations of zinc and copper in leaves than plants not treated with benomyl. These results suggest that the role of AMF in heavy metal uptake is metal specific. Based on this work, the use of benomyl on soils contaminated with Pb can be recommended in phytoextraction.