粘虫受中红侧沟茧蜂寄生后的生理变化

粘虫（Ｐｓｅｕｄａｌｅｔｉａ ｓｅｐａｒａｔａ）被中红侧沟茧蜂（Ｍｉｃｒｏｐｌｉｔｉｓ ｍｅｄｉａｔｏｒ）寄生以后生理生化上发生了一系列变化。通过被寄生粘虫的生长（体重）、发育（龄期）、血淋巴总蛋白含量和酚氧化酶活性等生理生化指标动态的研究,试图探讨中红侧沟茧蜂对寄主粘虫的生理调节方式和途径,进一步探讨寄生蜂同寄主相互协调、相互影响的关系。图６参２０     

The ability of conditioned Microplitis croceipes (Hymenoptera: Braconidae) to distinguish between odors of aflatoxigenic and non-aflatoxigenic fungal strains

Summary. The parasitic wasp Microplitis croceipes (Cresson) (Hymenoptera: Braconidae) learns to associate odors with food resources and subsequently exhibits a characteristic food-seeking behavior when encountering the learned odor. Wasps so conditioned, learned and subsequently demonstrated an ability to distinguish among aflatoxigenic and non-aflatoxigenic Aspergillus flavus and A. parasiticus strains. The effects of fungal species, strain, age (5, 10-12, 20, and 30 d) and growth media (potato dextrose agar, peanut agar and corn agar) on the learning and recognition responses of the conditioned wasps were examined. The level of differentiation between fungal strains by conditioned wasps was lowest when working with 5-d-old fungal cultures but increased with age and generally peaked with 20-d-old fungi. Wasps responded generally stronger to the fungal strain conditioned to independent of growth media. This ability of parasitic wasps to learn and distinguish fungal odors can open new avenues in insect learning.     

Responses of Some Terrestrial Invertebrates to Catchment Treatments Applied at Loch Fleet

The impact of liming and heather-burning on the beetle and spider faunas of open and afforested moorland was studied by use of pitfall traps. of the 168 species identified, the catch of only one species, the ground beetle Trechus obtusus Erichson, increased in a way that could be related to intervention treatments. No species obviously declined as a result of the intervention treatments.     

Utilizing transparent and conductive SnO2 as electron mediator to enhance the photocatalytic performance of Z-scheme Si-SnO2-TiOx

• A novel Z-scheme Si-SnO₂-TiO_x with SnO₂ as electron mediator is first constructed. • Transparent and conductive SnO₂ can pass light through and promote charge transport. • V_O from SnO₂ and TiO_x improve photoelectrochemical performances. • Efficient photocatalytic degradations originate from the Z scheme construction. Z-scheme photocatalysts, with strong redox ability, have a great potential for pollutants degradation. However, it is challenging to construct efficient Z-scheme photocatalysts because of their poor interfacial charge separation. Herein, by employing transparent and conductive SnO₂ as electron mediator to pass light through and promote interfacial charge transportation, a novel Z-scheme photocatalyst Si-SnO₂-TiO_{x (1<x<2)} was constructed. The Z-scheme photocatalyst displayed an order of magnitude higher photocurrent density and a 4-fold increase in open-circuit potential compared to those of Si. Moreover, the onset potential shifted negatively for approximately 2.2 V. Benefiting from these advantages, this Z-scheme Si-SnO₂-TiO_x exhibited efficient photocatalytic performance toward phenol degradation and mineralization. 75% of the phenol was degraded without bias potential and 70% of the TOC was removed during phenol degradation. Other typical pollutants such as bisphenol A and atrazine could also be degraded without bias potential. Introducing a transparent and conductive electron mediator to construct Z-scheme photocatalyst gives a new sight to the improvement of photocatalytic performance in Z scheme.     

无锡市经济社会转型及其乡村生态环境响应

应用弹性理论和灰色关联分析方法构建乡村生态环境与经济社会转型的响应模型,分析无锡市乡村生态环境对经济社会转型的响应过程及其耦合关系.结果表明,1978-2010年无锡乡村生态环境对经济社会转型表现为负向响应特征,响应强度曲线呈现出先增强后减弱的“倒抛物线”变化趋势;经济非农化是影响乡村生态环境的首要因素,1990年代中期以来的社会城市化以及2002年以来的经济外向化对乡村生态环境的影响不断加大;同时,乡村生态环境对经济社会转型也存在反馈约束作用,生态用地减少和环境质量下降是制约经济社会发展的显著因素.     

柿树被日本龟蜡蚧危害后挥发物的变化及其对红点唇瓢虫的引诱作用

研究了柿树(DiospyroskakiL.f.)受日本龟蜡蚧(CeroplastesjaponicusGreen)危害后,体内释放出的挥发性物质对天敌昆虫红点唇瓢虫(ChilocoruskuwanaeSilvestri)的招引作用.Y形嗅觉仪测定结果表明,瓢虫趋向受害枝叶的百分率为74.17%,明显大于趋向未受害枝叶的20.00%,t检验证明,二者间差异极显著;而受害轻微枝叶挥发物对红点唇瓢虫的诱导作用与未受害枝叶的诱导效果相比没有显著差异;说明日本龟蜡蚧对柿树的危害可诱导树体挥发性物质发生改变,增加了对红点唇瓢虫的引诱作用.经气相色谱/质谱联用仪(GC/MS)分析发现,柿树未受害枝叶挥发物共有29种组分,烃类物质的相对含量占92.98%;受害枝叶释放出的挥发物组分有32种,烃类物质的相对含量增加到97.15%,另外减少了3种醇类化合物和2种烷烃类化合物,同时合成了8种新的组分,包括4种烃类、3种萜类和1种酮类.这些新合成的化合物极有可能在不同程度上参与了对瓢虫的招引作用.本文揭示了柿树受日本龟蜡蚧危害后,诱导其挥发出对天敌昆虫有引诱作用的化学信息素,为进一步试验确定有效成分和人工筛选模拟引诱剂,开辟生物防治新途径提供了基础依据.图1表2参16     

藿香蓟(Ageratum conyzoides)对土壤铅胁迫的生理响应

为了解日益增加的城市土壤铅(Pb)胁迫对城市园林地被植物的影响,采用盆栽实验研究土壤Pb胁迫对藿香蓟(Ageratum conyzoides)叶片生理特性的影响.结果显示,Pb胁迫处理降低了藿香蓟叶片的叶绿素总量及叶绿素a和b含量,质膜透性增大,丙二醛(MDA)含量上升.随着Pb浓度增加,同一时期内藿香蓟叶片SOD、POD和CAT酶活性均上升,但土壤Pb浓度超过750 mg kg-1或1 000 mg kg-1后保护酶活性开始逐渐下降.随着胁迫处理时间的延长,SOD活性在d 20、d 40和d 60时都高于胁迫处理d 7时的活性,POD活性是在d 20时急剧下降,CAT活性则在胁迫处理d 60时急剧下降.研究表明,藿香蓟能在一定程度上适应土壤Pb胁迫,但Pb胁迫浓度超过750 mg kg-1后将影响其生理代谢过程.图4参20     

高山植物对全球气候变暖的响应研究进展

高山地区被认为是对全球气候变化最敏感的区域之一,气候变暖导致高山生境内生物与非生物环境因子发生不同程度的改变,从而引起高山植物从不同层面作出不同的变化或响应.综述了高山及亚高山高海拔生境内,植物从宏观生态系统层面到微观个体生理层面对全球气候变化进行响应的研究进展.植物由个体自身的生理及形态上产生不同响应,逐步经过"瀑布式上升效应(Cascade effects)",最后引起整个高山生态系统的转变.受局地差异性及物种差异性影响,生物多样性在不同高山地区呈现出或是增加或是减少的趋势;林线及植被向高纬度、高海拔地区扩张;植物间相互关系由协作转向中性乃至竞争;植物物候、繁殖、生物量生产、光合作用、年轮生长、营养结构等方面均呈现出不同的响应模式.这些从微观到宏观的不同响应模式,最终将引起高山生态系统在结构、功能上的改变,进而在很大范围上威胁到高山植物的生存与发展.最后提出该领域未来的研究重点.参147     

藻细胞膜电信号对重金属的快速反应研究

为探讨藻细胞膜电信号对重金属离子的响应特征,运用细胞外表面技术和电化学方法研究了淡水藻——大型轮藻(Nitellaflexilis)藻细胞膜电位和膜电阻对汞、镉、铅的快速反应.结果表明,细胞膜电位和膜电阻对汞、镉响应灵敏且快速,30min内即对1μmol·L-1Hg2+、Cd2+表现出超极化和膜电阻增大反应,而5、10μmol·L-1Hg2+、Cd2+则在15min内引起细胞去极化、膜电阻减小,且剂量效应显著.细胞膜电信号对Pb2+的响应浓度为100μmol·L-1,30min内细胞先去极化后超极化,膜电阻持续增大.重金属作用前后相比,高浓度Hg2+、Cd2+(5、10μmol·L-1)导致藻细胞不可逆损伤,而其低浓度所致的损伤可恢复.Pb2+致藻细胞不可逆损伤的最低浓度为500μmol·L-1.对比膜电信号对3种离子的响应特点,发现藻细胞膜电位和膜电阻对Hg2+和Cd2+的响应灵敏度大于Pb2+.     

2种茶树对铜胁迫的响应及其组织铜化学形态变化的比较研究

为了分析不同茶树对Cu胁迫的生理响应及其组织中不同化学形态Cu的累积特性,本研究采用水培法,探讨铁观音、肉桂2种茶树在不同浓度Cu胁迫下,茶树根系活力、叶绿素含量、茶树组织Cu含量及不同化学形态Cu含量的变化,以期为重金属对茶树毒害机理和茶树对重金属的自我防御研究提供理论依据。结果表明,随着Cu胁迫浓度的增加,茶树根系活力及叶片叶绿素含量呈现下降趋势,而与对照相比,铁观音下降的幅度远高于肉桂。不同茶树品种在相同浓度Cu胁迫下,其根、茎、叶组织的Cu含量差异不显著,而不同组织中则表现为根叶茎。不同化学形态Cu含量分析结果表明,随着Cu胁迫浓度的升高,2种茶树根部可交换态Cu、碳酸盐结合态Cu、有机结合态Cu含量百分比呈现下降趋势,而铁锰氧化态Cu和残留态Cu呈现上升趋势;茎部可交换态Cu、有机结合态Cu含量百分比呈现下降趋势,碳酸盐结合态Cu、铁锰氧化态Cu和残留态Cu呈现上升趋势;叶部可交换态Cu、碳酸盐结合态Cu、有机结合态Cu含量、铁锰氧化态Cu含量的百分比均呈现上升趋势,而残留态Cu呈现下降趋势。进一步分析发现,Cu胁迫下,铁观音茶树根、叶部主要以采取提高有机结合态Cu的形式来降低Cu离子毒害,而肉桂则以提高铁锰氧化态Cu形式降低Cu离子毒害,叶部则以提高铁锰氧化态Cu和残留态Cu的形式降低Cu离子毒害。可见,不同的茶树在Cu胁迫下所表现解毒模式存在着一定的差异。     

岩溶山区不同土地利用方式下土壤质量指标响应

探讨了岩溶山区不同土地利用方式与土壤质量指标之间的响应关系.对重庆市北碚岩溶山区土壤肥力指标进行主因子分析的结果表明,原有22个土壤质量指标可归为4 类,分别以有机质,有效含水量,通气孔隙度,细菌、真菌数量百分比为代表,这4类因子基本反映了土壤质量随土地利用变化的综合变化状况.通径分析表明,不同土地利用方式下土壤持水性能主要与有机质、＞0.25 mm水稳性团聚体有关,二者的效应均大于黏粒.在土地利用方式变化过程中,土壤质量变化体现在有机质含量、土壤供持水能力、土壤结构状况和土壤微生物特性的变化上.