大田常用杀虫剂对椰心叶甲及椰心叶甲啮小蜂的选择毒性

为协调椰心叶甲的化学防治与生物防治,在室内测定了丁硫克百威、氯氰菊酯、啶虫脒和椰甲清 4种杀虫剂对椰心叶甲卵、幼虫、蛹和成虫 4 个虫态及其寄生性天敌椰心叶甲啮小蜂卵、幼虫、蛹和成虫 4 个虫态的相对毒力。结果表明,椰甲清、氯氰菊酯、啶虫脒和丁硫克百威 4 种杀虫剂对椰心叶甲和椰心叶甲啮小蜂 成虫的益害毒性比分别为 3.864 6、2.388 4、0.548 5 和 0.083 1。在有效防治椰心叶甲的前提下,对天敌椰心叶甲啮小蜂的安全性依次为椰甲清 > 氯氰菊酯 > 啶虫脒 > 丁硫克百威。椰甲清和氯氰菊酯可在椰心叶甲综合治理中发挥有效的作用。     

抗啶虫脒椰心叶甲种群对椰甲截脉姬小峰和椰心叶甲啮小蜂抗药性选育的影响

筛选椰心叶甲对啶虫脒的抗药性,并以筛选后的椰心叶甲作为椰甲截脉姬小峰和椰心叶甲啮小蜂的寄主,观察这两种寄生蜂后代种群的抗性水平变化情况.结果表明,经筛选后,椰心叶甲的抗性水平增长了1.33倍,椰甲截脉姬小峰和椰心叶甲啮小蜂的抗性倍数分别增长了2.3倍和2.73倍,且椰心叶甲及其寄生蜂的后代种群抗性个体频率均显著高于初始种群.表明可利用椰心叶甲的抗药性来促进椰甲截脉姬小峰和椰心叶甲啮小蜂的抗性选育.     

不同发育阶段椰心叶甲对3种杀虫剂的敏感性

测定不同发育阶段椰心叶甲的药剂敏感性差异。结果表明,低龄幼虫和成虫对高效氯氰菊酯和阿维菌素的敏感性高于高龄幼虫、蛹和卵。幼虫和成虫对啶虫脒的敏感性高于蛹和卵。卵的药剂敏感性最低。低龄幼虫期为最佳防治适期。椰心叶甲对3种杀虫剂的敏感性大小为高效氯氰菊酯＞阿维菌素＞啶虫脒。随着幼虫的发育,其体重由小变大,对高效氯氰菊酯和啶虫脒的敏感性降低,而幼虫对阿维菌素的敏感性与体重相关不显著。     

椰甲截脉姬小蜂对寄主龄期的选择性和适合性

研究了椰甲截脉姬小蜂对寄主椰心叶甲各龄幼虫的选择性。结果表明:椰甲截脉姬小蜂可寄生椰心叶甲各龄幼虫,但偏爱寄生2,3龄幼虫,选择系数分别为0.33825和0.31348,极显著高于1,4,5龄幼虫。寄生各龄椰心叶甲幼虫的姬小蜂在羽化率、每寄主育出蜂数2指标中存在差异,寄生4龄幼虫的处理中,羽化率和每寄主育出蜂数分别为71.03%和40.87头,明显高于寄生其他龄期的幼虫,因此4龄椰心叶甲幼虫对椰甲截脉姬小蜂的生长发育最适合。     

海南省刺桐姬小蜂危害情况调查及防治药剂初筛

调查海南省18个市县刺桐姬小蜂的危害情况,发现除东方县、白沙县外,其余市县均有不同程度的危害;选用6种不同杀虫剂对刺桐姬小蜂进行室内药效试验。结果表明,作用效果：48% 毒死蜱EC＞70% 吡虫啉WP和25% 噻虫嗪WDG＞20% 啶虫脒WP＞乙酰甲胺磷EC和1.65% 阿维菌素·高效氯氰菊酯WP。     

取食不同寄主植物椰心叶甲后代对杀虫剂的敏感性差异

测定了不同寄主植物饲养的椰心叶甲种群对3种杀虫剂的敏感性变化情况。结果表明,取食不同食料的椰心叶甲后代对啶虫脒敏感性顺序为:鱼尾葵>酒瓶椰子>大王棕>椰子叶,对高效氯氰菊酯敏感性顺序为:鱼尾葵>酒瓶椰子>椰子叶>大王棕,对阿维菌素敏感性顺序为:酒瓶椰子>椰子叶>大王棕>鱼尾葵;其中对阿维菌素的敏感性差异幅度最大,为14.18倍,对高效氯氰菊酯和啶虫脒的敏感性差异幅度较小,分别为3.47倍和2.54倍。表明取食不同的寄主植物可引起椰心叶甲对杀虫剂的敏感性变化。     

营养条件和寄主密度对椰甲截脉姬小蜂子代的影响

椰甲截脉姬小蜂(Asecodes hispinarum Boucˇek)是椰心叶甲[Brontispa longissima(Gestro)]害虫的重要内寄生蜂,主要寄生害虫的4龄幼虫。为了更好地为室内繁殖寄生蜂提供理论依据,开展了营养条件和寄主密度的改变对椰甲截脉姬小蜂子代的影响。结果表明:(1)补充10%蜂蜜水作为营养的情况下,椰甲截脉姬小蜂寄生能力随寄主密度不同存在差异。每对寄生蜂在寄主数量为5时,被寄生的椰心叶甲数量最多,为2.33头。当寄主密度大于5时,椰心叶甲被寄生的数量有随寄主密度增加而降低的趋势;不补充营养时,寄生蜂的寄生能力差异不显著。(2)补充10%蜂蜜水时,寄主密度对每寄主出蜂量、椰甲截脉姬小蜂羽化率和后代性比并无显著影响。(3)不补充营养时,寄主密度对每寄主出蜂量和椰甲截脉姬小蜂后代性比均有显著影响,对椰甲截脉姬小蜂羽化率无影响,每寄主出蜂数量最多为45.67头,后代性比最高为96.66%。     

椰心叶甲两种寄生蜂过冷却点及冰点测定

椰甲截脉姬小蜂和椰扁甲啮小蜂是入侵性害虫椰心叶甲的重要天敌。为了了解这两种寄生蜂的耐寒能力,测定了椰甲截脉姬小蜂和椰扁甲啮小蜂不同发育阶段的过冷却点和冰点。从过冷却点和冰点来看,椰甲截脉姬小蜂和椰扁甲啮小蜂具有一定的耐寒能力,可在椰心叶甲发生区越冬存活。两种寄生蜂的过冷却点和冰点不同发育阶段有所不同。寄生蜂蛹的过冷却点和冰点最高。雌、雄蜂之间的过冷却点和冰点皆没有显著差异。笔者认为,椰甲截脉姬小蜂和椰扁甲啮小蜂可在中国椰心叶甲所有发生区释放应用。     

三亚市椰心叶甲寄生蜂的防效调查

先后2次对海南三亚市椰心叶甲放蜂点进行寄生蜂防治效果调查,从放蜂点分布、椰树危害程度、虫口密度和寄生蜂寄生率等4个方面评价椰心叶甲啮小蜂和椰甲截脉姬小蜂对椰心叶甲的防控效果。结果表明：三亚的椰树危害程度在逐渐减轻,轻度危害的椰树已占调查点的60％,虫口密度已明显下降。从两种寄生蜂的分布情况来看,椰心叶甲啮小蜂在三亚的分布范围在扩大,已经分布在每个调查点,椰甲截脉姬小蜂的分布范围则略有缩小。两种寄生蜂的寄生率比较来看,椰心叶甲啮小蜂较2007年高,而椰甲截脉姬小蜂在三亚的寄生率较2007年差。说明了两种寄生蜂均可以在三亚寄生生存,椰心叶甲啮小蜂在三亚的生存能力更强,对椰心叶甲的防控效果比椰甲截脉姬小蜂好。本研究对如何利用寄生蜂来控制椰心叶甲,具有重要的参考意义。     

利用寄生蜂防治椰心叶甲的概况及研究展望

按天敌引进和利用的顺序综述应用寄生蜂防治椰心叶甲的概况，包括引进天敌的种类与可行性分析、引进流程与安全性评估、椰甲截脉姬小峰和椰心叶甲啮小蜂的基础生物学与人工繁育，以及释放技术和跟踪评价技术，讨论并展望未来研究和应用椰甲截脉姬小峰和椰心叶甲啮小蜂等问题。     

Solvent transport phenomenon of cellulose microfiber (CMF) reinforced poly (ethylene-co-vinyl acetate) (EVA) composites

Composite films based on EVA with CMF were prepared and characterized for their solvent transport nature. CMF were derived from Hibiscus sabdariffa by steam explosion technique and incorporated in the EVA matrix by extrusion. Solvent transport by the composites was analyzed using hexane, heptane and octane as penetrant molecules. The solvent uptake behavior of EVA/CMF composites is explained on the basis of the penetrant size, temperature and the filler loading. The composite had improved barrier property compared with unfilled EVA. This in turn is an indication of good fiber-matrix interaction in the composite system. Diffusion parameters such as diffusion coefficient, permeation coefficient and Arrhenius activation parameters and thermodynamic parameters such as enthalpy and entropy were evaluated in detail. The mode of transport was found to be Fickian.     

Thermal degradation behaviors and fire retardant properties of poly(1,3,4-oxadiazole)s (POD) and poly(m-phenylene isophthalamide) (PMIA) fibers

Thermal degradation behaviors and fire retardant properties of poly(1,3,4-oxadiazole)s (POD) and poly(m-phenylene isophthalamide) (PMIA) fibers were investigated. The thermal gravimetric analysis (TGA) demonstrated that POD exhibited higher onset thermal degradation temperature (T_onset) than PMIA, exceeding nearly 80 °C. The thermal degradation kinetics, evaluated by the modified Coats-Redfern method, displayed that the apparent activation energy (E_a) of POD and PMIA fibers was similar when the conversion rate (α) ranges from 0.2 to 0.5, while with the α from 0.6 to 0.8, the E_a of POD was significantly lower than that of PMIA. The fire retardant performance of POD and PMIA fibers were evaluated by cone calorimeter under heat fluxes of 35, 50 and 75 kW/m², during which the temperature of the fibers were monitored by a thermocouple. Surprisingly, POD fibers showed inferior fire retardant performance in comparison with PMIA, with lower time to ignition (TTI) and higher peak heat release rate (PHRR). The origin of the different fire retardant properties of both fibers was revealed by analyzing the residual chars and gaseous products during thermal pyrolysis. The morphology confirmed that stable and compact chars can be formed in PMIA. In addition, the Fourier Transform Infrared Spectroscopy (FTIR) characterization of the residual char revealed that POD can form carbonaceous chars at the heat flux of 50 kW/m², while the heat flux of PMIA was 75 kW/m². The pyrolysis products characterized by pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) indicated that POD can be pyrolyzed completely at 600 °C, while the temperature of PMIA was 700 °C.     

Hydraulic Resistance of Sorghum (C4) and Sunflower (C3)

Summary

It is well known that C4 crops have a lower water requirement than C3 crops. Reasons for the difference are not well understood. Therefore, hydraulic resistance of sorghum [Sorghum bicolor (L.) Moench] (C4) and sunflower (Helianthus annuus L.) (C3) was determined to see if it might be one explanation for the lower water use of crops with the C4 photosynthetic pathway. Plants were grown under greenhouse conditions in pots with soil, which was well watered (soil matric potential of ～0 MPa) or allowed to dry (soil matric potential of ?0.038 MPa and ?0.065 MPa for sorghum and sunflower, respectively). Hydraulic resistance was calculated in two ways: (1) using the classic Ohm's law analogue, which assumes that the relation between flux (transpiration) and difference in water potentials of the soil and plant is linear and (2) using an equation that considers diurnal changes in leaf water content along with transpiration and difference in water potentials. Because change in leaf-water content during a day was small, hydraulic resistances calculated by the two methods resulted in similar values. Sorghum had a linear relationship between flux and difference in potentials (constant hydraulic resistance), but sunflower had a nonlinear one (variable hydraulic resistance). The hydraulic resistance of watered sunflower increased only slightly during a day and averaged about 40 MPa m² s mol^?1, which was 3.5 times less than that of watered or water-stressed sorghum (-140 MPa m² s mol^?1). The hydraulic resistance of water-stressed sunflower increased steeply during a day and by the end of the day it had a hydraulic resistance that approached that of sorghum.     

茶叶多糖铁的合成及其铁含量的测定

用热水浸泡法从粗老茶叶中提取茶叶多糖,在碱性条件下,茶叶多糖水溶液与三氯化铁反应合成茶叶多糖铁配合物(TPC),并用邻菲罗啉分光光度法和原子吸收光谱法测定TPC中铁(Ⅲ)的含量。实验结果表明:TPC是深棕红色无定型粉末,易溶于水,在pH值3~12范围内不沉淀,不水解。TPC中铁(Ⅲ)的含量:邻菲罗啉分光光度法测定结果为20.71%,原子吸收光谱法测定结果为20.13%。     

Life history of Closterotomus (Calocoris) trivialis (Costa) (Heteroptera: Miridae) in olive and citrus orchards in Crete

The population density of Closterotomus trivialis (Costa) and its damage potential were studied in citrus and olive orchards of Crete. C. trivialis was found to be most abundant in wild radish Raphanus raphanistrum L., annual mercury Mercurialis annua L., Urtica sp. and upright pellitory Parietaria officinalis L. compared to mallow Malva sylvestris L., prickly goldenfleece Uropermum picroides (L.), sowthistle Sonchus oleraceus L., citrus or olive trees. Its damage potential on the setting of olive fruit was investigated at the early inflorescence stage. When 1, 5 or 10 adults of C. trivialis were enclosed with stems at the 55th and 57th phenological growth stages, the number of fruits was significantly reduced compared to controls.The developmental biology of individuals of C. trivialis was studied on R. raphanistrum at seven constant temperatures 15, 20, 25, 30, 32.5, 35 and 37 °C, under laboratory conditions. No nymphs survived above 35 °C. The highest nymph to adult survival (89.6%) was found at 20 °C and the lowest (40.6%) at 32.5 °C. Mean developmental time as well as adult longevity decreased with increasing temperature. The developmental time from 1st nymphal instar to adult ranged from at least 9.0 at 32.5 °C to 27.8 days at 15 °C. The adults lived from 2.9 days at 32.5 °C to 45.3 days at 15 °C. It required 212.7 degree-days to complete development above a minimum threshold of 7.72 °C as estimated by linear regression and 8 °C as estimated by nonlinear model. The importance of these findings in the management of this species through the prediction of its seasonal appearance is discussed.     

Organic-inorganic hybrid of chitosan/poly (vinyl alcohol) containing yttrium(III) membrane for the removal of Cr(VI)

In this present study, an organic-inorganic hybrid membrane was prepared by embedding yttrium(III) into chitosan matrix for the removal of Cr(VI) from aqueous solutions. Several techniques, including fourier infrared spectrum (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), and transmission electron microscope (TEM) are employed to characterize the properties of the membrane. The mechanical properties of the membrane were also examined. The chitosan/poly(vinyl alcohol) containing yttrium(III) (CY) membrane was experimentally used for the removal of Cr(VI) ions from aqueous solution under the optimized conditions. The results showed that the adsorption capacity for the removal of Cr(VI) ions was enhanced when yttrium(III) was introduced. The adsorption data from the experiment were fit well by Langmuir isotherm. Based on Langmuir model, q _m was calculated to be 38.48 mg g^?1. Kinetic study results indicated that the adsorption process followed a pseudo-second-order kinetics.     

绿茶成分EGCG抗肿瘤作用研究进展

表没食子儿茶素没食子酸酯(EGCG)是绿茶的主要活性成分.近年来越来越多的科学工作者将注意力集中在儿茶素单体EGCG的抗肿瘤作用上,证实了EGCG具有广泛的生物学特性和药理效应,能够抑制多种肿瘤的形成和发生,是茶叶中抗肿瘤效应的主要活性成分,本文就近年来国内外EGCG抗肿瘤作用机制研究进行综述.     

Host suitability of three avocado cultivars (Persea americana Miller: Lauraceae) to oriental fruit fly (Bactrocera (invadens) dorsalis (Hendel) (Diptera: Tephritidae))

The oriental (invasive) fruit fly Bactrocera (invadens) dorsalis (Hendel) (Diptera: Tephritidae) has invaded Africa and is currently established in over 30 countries and has caused in massive fruit losses. Avocado (Persea americana Miller) is among the fruit with which the pest is associated. The aim of the study was to determine the host status of a ‘black-skinned’ cultivar “Hass” and two ‘green-skinned’ cultivars “Pinkerton” and “Fuerte” to B. (invadens) dorsalis. In the laboratory study conducted in Kenya in 2012 and 2013, punctured and unpunctured recently-harvested fruit were exposed to sexually-mature fruit fly in ‘no-choice’ experiments. B. (invadens) dorsalis readily developed in the punctured fruit but not in the uncompromised fruit (fruit not damaged by insects or handling). This result was confirmed in Tanzania in 2013 where flies were introduced to unpunctured fruit. In the field studies the fruit of each cultivar were caged in situ with flies for 72 h. On dissection only fruit damaged by false codling moth (Thaumatotibia leucotreta (Meyrick)) were found to harbor B. (invadens) dorsalis. In the light of these results the risk imposed for “Hass”, “Pinkerton” and “Fuerte” by B. (invadens) dorsalis is negligible under standard export conditions. The findings of this study and the implications to regional and international trade are discussed.