温度对加州新小绥螨以截形叶螨为猎物的发育及繁殖的影响

在15～35℃、RH80%～85%条件下,研究了加州新小绥螨Neoseiulus (Amblyseius) californicus (Mcgregor)以截形叶螨Tetranychus truncatus Ehara为猎物时,不同螨态的发育和实验种群生命表。结果表明,加州新小绥螨在此温度范围内能完成世代发育,世代发育历期随着温度升高而逐渐缩短。该螨能适应35℃的高温条件,雌性的发育历期最短仅为6.14d。平均产卵期和平均寿命均随着温度的上升逐渐缩短。20℃～25℃时,该螨的平均产卵量最大,达53.73粒/雌。净增殖率在20℃时最高(48.2525),且雌雄性比最大。15℃时内禀增长率和周限增长率均最低,分别为0.0638和1.0659,种群倍增时间最长(10.8669d),35℃时内禀增长率和周限增长率均最高,分别为0.1954和1.2158,种群倍增时间最短(3.5477d)。     

斯氏新小绥螨以神泽氏叶螨为猎物的发育与实验种群生命表研究

本研究进行了斯氏新小绥螨Neoseiulus swirskii （Athias-Henriot）以神泽氏叶螨Tetranychus kanzawai（Kishida）为猎物时,在15℃、18℃、20℃、25℃、30℃和35℃下的发育历期和实验种群生命表的研究,结果表明15℃时斯氏新小绥螨不能完成发育,18℃时仅少量个体能完成发育.在18～35℃之间,雌螨的发育历期为7.15～18.70 d,雄螨的发育历期为4.00～16.20 d.在20℃～35℃之间,斯氏新小绥螨的雌雄性比（♀∶♂）随着温度的升高而变小,20℃时性比最大（1.77）,25℃时净增殖率（R0）最大（36.497）,35℃时世代生长周期最短（15.433）,30℃时内禀增长率（rm）和周限增长率（λ）均最大,分别为0.197和1.218,种群倍增时间（t）最短（3.513）;随着温度的增加,斯氏新小绥螨的平均寿命逐渐变短,20℃时最长（73.40±1.26 d）,35℃时最短（25.10±1.20d）;25℃时每雌平均产卵量最高（60.44±1.51粒/雌）,35℃时日平均产卵量最高（2.06±0.09粒/雌/d）.     

温度和光照对朱砂叶螨实验种群的综合效应

长短光照对朱砂叶螨(蜱螨目:叶螨科)的影响有着显著差异。在接近滞育温度(15℃)的20℃时,短光照明显加速叶螨发育,提高种群内禀增长率r_m值;在适温以上则延缓叶螨发育,r_m值相应降低。种群生殖的最适温度长光熙时是25℃,短光照时是30℃。长光照35℃时发育速率最大,r_m(0.3425)最高,种群加倍所需日数最短(1.91天)。各项种群生命参数与温度间的数学关系可分为4类:(1)逻辑斯谛关系:发育时间、5％死亡时间和世代平均时间的倒数值,产卵率(粒/天/♀);(2)直线关系:雌螨寿命,产卵期,r_m和周限增长率(λ);(3)抛物线关系:产卵量(粒/♀),净生殖率(R_0);(4)双曲线关系:种群加倍所需日数。     

胡瓜新小绥螨和尼氏真绥螨生物学特性比较研究

胡瓜新小绥螨Neoseiulus cucumeris和尼氏真绥螨Euseius nicholsi是重要的捕食性天敌,其中前者为引进种类,后者为本地种类。本文在室内25℃条件下,以粉螨为食料饲养胡瓜新小绥螨,以二斑叶螨为食料饲养尼氏真绥螨,组建生殖率表,结果表明：胡瓜新小绥螨的产卵量（平均36.35±5.56粒/雌）、內禀增长率（rm=0.0942）、周限增长率（λ=1.0988）均高于尼氏真绥螨的平均产卵量29.78±3.11粒/雌、内禀增长率rm=0.0827、周限增长率λ=1.0863,且种群倍增时间（t=7.35 d）也较尼氏真绥螨（t=8.38 d）短。通过各参数的比较,在恒温25℃条件下,胡瓜新小绥螨具有较大的生殖潜力。在以桔全爪螨为食料,进行混合饲养时,两种捕食螨的种群增长均受到抑制,而尼氏真绥螨受到的抑制更明显。说明胡瓜新小绥螨竞争力强于尼氏真绥螨。     

胡瓜钝绥螨捕食茶橙瘿螨的实验种群生命表及捕食作用初探

本在25℃条件下初步研究了胡瓜钝绥螨捕食茶橙瘿螨的实验种群生命表、各螨态取食量及猎物－－卵转化率。25℃时胡瓜钝绥螨的净增殖率R0＝21．7862,世代平均周期T＝16．1822,内禀增长率rm＝0．1904,周限增长率λ＝1．2097,种群倍增所需时间t＝3．6405。日平均产卵量2．19粒／天,总产卵量36－48粒／雌,平均38．97粒／雌。胡瓜钝绥螨雌螨－生取食量1978．49头。雄螨取食量879．56头。猎物：卵转化率为79．78头茶橙瘿螨：2．19粒胡瓜钝绥螨卵。     

温度对微小花蝽生长发育和繁殖的影响

【目的】明确温度对微小花蝽Orius minutus生长发育和繁殖的影响。【方法】本研究以腐食酪螨Tyrophagus putresceniae为猎物,分别在5个恒温(15,20,25,30和35℃)条件下室内饲养,调查了温度对微小花蝽各虫态发育历期、存活率、成虫繁殖力以及种群参数的影响。【结果】在15~35℃范围内,各虫态平均发育历期均随温度升高而缩短,15℃下完成一个世代发育需要52.45 d,而35℃下仅需14.85 d。直线回归分析表明,微小花蝽世代发育起点温度为8.89℃,有效积温为359.20日·度。世代存活率和单雌平均产卵量均在25℃时最高,分别为17.07%和41.00粒。种群趋势指数在15℃和35℃下小于1,种群呈负增长;20~30℃下大于1,且25℃时最高,为3.92。净增殖率、内禀增长率和周限增长率均在25℃时最高,分别为3.32,0.04和1.04;种群世代周期以15℃时最长,为57.76 d,35℃时最短,为17.50 d。【结论】取食腐食酪螨的微小花蝽发育适宜温度范围为25~35℃,存活、繁殖和种群增长的最适温度均为25℃。这些结果为利用腐食酪螨人工饲养微小花蝽提供了基础参考数据。     

南非盲走螨实验种群的发育历期及生命表

在27℃条件下,以粗脚粉螨Acarus siro L.为饲料饲养观察南非盲走螨Typhlodromus(Anthoseius) transvaalensis(Nesbitt)的生长发育和繁殖情况,组建实验种群生命表。结果表明,南非盲走螨行孤雌生殖,卵、幼螨、前若螨、后若螨、成螨产卵前期各阶段发育历期分别为2.00,0.72,1.96,1.53,1.77d,完成1个世代发育需7.98d,雌成螨平均寿命14.82d、平均产卵量25.75粒,各种群生命参数分别为:净增殖率R0=25.01,世代平均周期T=13.71,内禀增长率rm=0.23,周限增长率λ=1.26,种群倍增所需日数t=2.95。采用小空间湿度控制法,测定不同湿度对南非盲走螨卵的孵化和成螨产卵的影响。结果表明,卵发育和孵化的最适湿度为75.0%~85.0%,96.0%的相对高湿度对成螨的产卵和存活均有不利影响。以橘全爪螨Panonychus citri McGregor不同螨态为猎物时,南非盲走螨对橘全爪螨幼螨的捕食量最大,日平均捕食量为5.40头,而对橘全爪螨雌成螨则几乎不取食。     

朱砂叶螨实验种群的孤雌生殖效应

在温度28±1℃,相对湿度65±5％的条件下,室内以蚕豆叶饲养朱砂叶螨。连续观察3个世代,世代平均历期25.12 d,其中卵平均历期4.34 d,幼螨平均历期2.01 d,若螨平均历期4.66 d,雌螨平均产卵历期14.16 d;组建朱砂叶螨实验种群连续3个世代的生命表。实验结果表明:孤雌生殖对朱砂叶螨实验种群具有强烈的影响作用,表现在缩短了雌螨的产卵历期,使雌螨的产卵高峰期提前,提高了种群的死亡率,降低了种群的净繁殖率、内禀增长率以及周限增长率。同时发现朱砂叶螨实验种群对世代历期、单雌卵量、性比具有极强的保持能力,孤雌生殖对这些指标的影响不能遗传给下一代。     

温湿度对神泽氏叶螨发育历期和产卵量的影响

将神泽氏叶螨Tetranychus kanzawai Kishida分别置于15℃,RH80%;20℃,RH75%;25℃,RH70%;30℃,RH65%;35℃,RH60%的恒温恒湿箱内单个饲养,观察其个体发育、孵化率、存活率和产卵量,结果为：35℃,RH60%条件下,雌、雄一代发育历期最短,为(6.23±0.44)山成螨最高日产卵量13.95±3.72)粒;平均日产卵量7.18±1.56)粒; 从成螨开始产卵至死亡50%产卵期最短,为(9.65±1.53)山卵孵化率72.4%;幼螨存活率84.6%。15℃,RH80%条件下,雌、雄一代发育历期最长,为(27.49±2.23)山成螨最高日产卵量(5±1.21)粒;平均日产卵量(2.04±0.55)粒;从成螨开始产卵至死亡50%产卵期最长,为(28.4±4.06)d：卵孵化率85.6%;幼螨存活率97.0%。15℃,RH80%处理成螨寿命为(35±8.85)d,比20℃,75%处理成螨寿命长(13.9±6.4)d。试验结果表明,不同的温湿度对神泽氏叶螨生长发育有一定的影响,35℃发育速率最快,15℃发育速率最慢,20～30℃为最适发育温度。     

温度对拟小食螨瓢虫发育和繁殖的影响

拟小食螨瓢虫是热带地区香蕉、番木瓜、橡胶和木薯等作物上有害叶螨的重要天敌。在室内条件下,以皮氏叶螨Tetranychus piercei为食物,观察了不同温度(16℃,20℃,24℃,28℃,32℃)对拟小食螨瓢虫生长发育及繁殖的影响。结果表明:拟小食螨瓢虫卵、幼虫和蛹的历期在32℃下最短,分别为2.38,4.26和3.04 d;16℃时最长,分别为12.48,25.10和16.12 d,雌成虫寿命在16℃时长达142.53 d,而在32℃时为95.46 d。世代发育起点温度和有效积温分别为13.29℃和227.63日度。成虫产卵量在28℃最高,达595.49粒/雌,在16℃最低,为125.05粒/雌。内禀增长率(rm)在32℃达到最大(0.2063),而在16℃时最小(0.0342)。结果表明拟小食螨瓢虫有较好的高温耐受性,研究结果可为该瓢虫人工繁育的温度条件提供依据。     

Collagen-like triple helix formation of synthetic (Pro-Pro-Gly)10 analogues: (4(S)-hydroxyprolyl-4(R)-hydroxyprolyl-Gly)10, (4(R)-hydroxyprolyl-4(R)-hydroxyprolyl-Gly)10 and (4(S)-fluoroprolyl-4(R)-fluoroprolyl-Gly)10.

For the rational design of a stable collagen triple helix according to the conventional rule that the pyrrolidine puckerings of Pro, 4-hydroxyproline (Hyp) and 4-fluoroproline (fPro) should be down at the X-position and up at the Y-position in the X-Y-Gly repeated sequence for enhancing the triple helix propensities of collagen model peptides, a series of peptides were prepared in which X- and Y-positions were altogether occupied by Hyp(R), Hyp(S), fPro(R) or fPro(S). Contrary to our presumption that inducing the X-Y residues to adopt a down-up conformation would result in an increase in the thermal stability of peptides, the triple helices of (Hyp(S)-Hyp(R)-Gly)(10) and (fPro(S)-fPro(R)-Gly)(10) were less stable than those of (Pro-Hyp(R)-Gly)(10) and (Pro-fPro(R)-Gly)(10), respectively. As reported by B?chinger's and Zagari's groups, (Hyp(R)-Hyp(R)-Gly)(10) which could have an up-up conformation unfavorable for the triple helix, formed a triple helix that has a high thermal stability close to that of (Pro-Hyp(R)-Gly)(10). These results clearly show that the empirical rule based on the conformational preference of pyrrolidine ring at each of X and Y residues should not be regarded as still valid, at least for predicting the stability of collagen models in which both X and Y residues have electronegative groups at the 4-position.     

Synthesis and luminescence properties of a blue-emitting Sr(3.5) Y(6.5) O(2) (PO(4) )(1.5) (SiO(4) )(4.5) :Eu(2+) phosphor

A novel blue‐emitting Sr_3.5Y_6.5O₂(PO₄)_1.5(SiO₄)_4.5:Eu²⁺ phosphor was synthesized via a solid‐state reaction. Powder X‐ray diffraction (XRD) analysis demonstrated that the Sr_3.5Y_6.5O₂(PO₄)_1.5(SiO₄)_4.5 host had a hexagonal crystal structure in the space group P6₃/m and unit cell parameters a = 9.418 Å, c = 6.900 Å. The as‐prepared phosphor showed a blue emission and all the main emission peaks were located at around 466 nm for different excitation wavelengths of 297, 333 and 391 nm. The temperature dependence of the photoluminescence property was investigated in the range 20–250 °C, and the emission intensity decreased to 71% of the initial value at room temperature on increasing the temperature to 150 °C. According to the classical theory of fluorescent thermal quenching, the activation energy (ΔE) for the thermal quenching luminescence of the as‐prepared Sr_3.45Y_6.5O₂(PO₄)_1.5(SiO₄)_4.5:0.05Eu²⁺ phosphor was determined to be 0.20 eV. Copyright © 2011 John Wiley & Sons, Ltd.     

Role of tfdC(I)D(I)E(I)F(I) and tfdD(II)C(II)E(II)F(II) gene modules in catabolism of 3-chlorobenzoate by Ralstonia eutropha JMP134(pJP4)

The enzymes chlorocatechol-1,2-dioxygenase, chloromuconate cycloisomerase, dienelactone hydrolase, and maleylacetate reductase allow Ralstonia eutropha JMP134(pJP4) to degrade chlorocatechols formed during growth in 2,4-dichlorophenoxyacetate or 3-chlorobenzoate (3-CB). There are two gene modules located in plasmid pJP4, tfdC(I)D(I)E(I)F(I) (module I) and tfdD(II)C(II)E(II)F(II) (module II), putatively encoding these enzymes. To assess the role of both tfd modules in the degradation of chloroaromatics, each module was cloned into the medium-copy-number plasmid vector pBBR1MCS-2 under the control of the tfdR regulatory gene. These constructs were introduced into R. eutropha JMP222 (a JMP134 derivative lacking pJP4) and Pseudomonas putida KT2442, two strains able to transform 3-CB into chlorocatechols. Specific activities in cell extracts of chlorocatechol-1,2-dioxygenase (tfdC), chloromuconate cycloisomerase (tfdD), and dienelactone hydrolase (tfdE) were 2 to 50 times higher for microorganisms containing module I compared to those containing module II. In contrast, a significantly (50-fold) higher activity of maleylacetate reductase (tfdF) was observed in cell extracts of microorganisms containing module II compared to module I. The R. eutropha JMP222 derivative containing tfdR-tfdC(I)D(I)E(I)F(I) grew four times faster in liquid cultures with 3-CB as a sole carbon and energy source than in cultures containing tfdR-tfdD(II)C(II)E(II)F(II). In the case of P. putida KT2442, only the derivative containing module I was able to grow in liquid cultures of 3-CB. These results indicate that efficient degradation of 3-CB by R. eutropha JMP134(pJP4) requires the two tfd modules such that TfdCDE is likely supplied primarily by module I, while TfdF is likely supplied by module II.     

The helix-coil transitions of poly (dA)-poly (dT) and poly (dA-dT)-poly (dA-dT)

Helix–coil transition curves are calculated for poly (dA) poly(dT) and poly (dA-dT) poly (dA-dT) using the integral equation approach of Goel and Montroll.⁵ The transitions are described by the loop entropy model with the exponent of the loop entropy factor, k, remaining an arbitrary constant. The theoretical calculations are compared with experimental transition curves of the two polymers. Results indicate that the stacking energies for these two polymers differ by about 1 kcal/mole of base pairs. Also, a fit between theory and experiment was not possible for k > 1.70.     

Induction of in vitro flowering in Dendrobium Madame Thong-In (Orchidaceae) seedlings is associated with increase in endogenous N(6)-(Delta (2)-isopentenyl)-adenine (iP) and N (6)-(Delta (2)-isopentenyl)-adenosine (iPA) levels

We analysed the endogenous cytokinin levels of Dendrobium Madame Thong-In seedlings grown in vitro during vegetative and flowering-inductive periods. HPLC was used to fractionate the extracts and radioimmunoassay (RIA) was used for assay of zeatin (Z), dihydrozeatin (DZ), N(6)-(Delta(2)-isopentenyl)-adenine (iP) and their derivatives. Coconut water used in experiments was found to contain high level (>136 pmol ml(-1)) of zeatin riboside (ZR). Protocorms and seedlings cultured in medium with coconut water were found to contain 0.5-3.9 pmol g(-1) FW of the cytokinins analysed. Seedlings (1.0-1.5 cm) cultured in flowering-inductive liquid medium containing 6-benzyladenine (BA, 4.4 muM) and coconut water (CW, 15%) contained up to 200 and 133 pmol g(-1) FW of iP and iPA, respectively. These levels were significantly higher than all other cytokinins analysed in seedlings of the same stage and were about 80- to 150-folds higher than seedlings cultured in non-inductive medium. During the transitional (vegetative to reproductive) stage, the endogenous levels of iP (178 pmol g(-1) FW) and iPA (63 pmol g(-1) FW) were also significantly higher than cytokinins in the zeatine (Z) and dihydrozeatin (DZ) families in the same seedlings. Seedlings that grew on inductive medium but remained vegetative contained lower levels of iPA. The importance of the profiles of iP and its derivatives in induction of in vitro flowering of D. Madame Thong-In is discussed.     

Biology of Bactrocera (Zeugodacus) tau (Walker) (Diptera: Tephritidae)

The biology of the fruit fly Bactrocera tau, an important horticultural pest, was studied under laboratory conditions at 25°C and 60–70% relative humidity on Cucurbita maxima. The duration of mating averaged 408.03 ± 235.93 min. After mating, the female fly had a preoviposition period of 11.7 ± 4.49 days. The oviposition rate was 9.9 ± 8.50 eggs and fecundity was 464.6 ± 67.98 eggs/female. Eggs were elliptical, smooth and shiny white, turning darker as hatching approached, and measured 1.30 ± 0.07 mm × 0.24 ± 0.04 mm. The chorion has polygonal microsculpturing and is species-specific with polygonal walls. The egg period lasts for 1.3 ± 0.41 days. The duration of the larval period is 1.2 ± 0.42, 1.7 ± 0.48 and 4.0 ± 0.94 days for first, second and third instars, respectively. Pupation occurs in the sand or soil and pupal periods are 7.0 ± 0.47 days. The life cycle from egg to adult was completed in 14.2 ± 1.69 days; the longevity of mated females and males was 130.33 ± 14.18 and 104.66 ± 31.21 days, respectively. At least two to three generations were observed from June 2008 to June 2009.     

Spectroscopic investigations of Er(3+) :CdO-Bi(2) O(3) -B(2) O(3) glasses

This article reports on the optical properties of Er³⁺ ions doped CdO–Bi₂O₃–B₂O₃ (CdBiB) glasses. The materials were characterized by optical absorption and emission spectra. By using Judd–Ofelt theory, the intensity parameters Ω_λ (λ = 2, 4, 6) and also oscillatory strengths were calculated from the absorption spectra. The results were used to compute the radiative properties of Er³⁺:CdBiB glasses. The concentration quenching and energy transfer from Yb³⁺–Er³⁺ were explained. The stimulated emission cross‐section, full width at half maximum (FWHM) and FWHM × values are also calculated for all the Er³⁺:CdBiB glasses. Copyright © 2011 John Wiley & Sons, Ltd.     

Cationic (tripyrrinato)palladium(II) complexes

The formation of cationic palladium(II)complexes [TrpyPd^II]⁺X⁻ by salt metathesis of the respective trifluoroacetates with different salts of weakly coordinating anions X⁻ was investigated. With non-hydrolizable counterions, cationic mono- and dinuclear complexes are observed depending on the nature of the anion X⁻ and the solvent. The mononuclear cations, which are only formed with X = BAr^F, most probably carry a weakly bound molecule of dichloromethane at the fourth coordination site of Pd^II. When treated with diazoalkanes, only these are sufficiently reactive to form carbene complexes. Four- and five coordinate Lewis base adducts [TrpyPd^IIL]⁺ with L = CH₃NC, tBuNH₂, PMe₃, PEt₃ and PiPr₃ and [TrpyPd^IIL₂]⁺ with L = PMe₃ were prepared from the mononuclear cations [TrpyPd^II]⁺BAr^F−. From structural studies it becomes apparent, that the formation of stable five coordinate Pd^II species is restricted to medium size ligands and depends on the delicate balance between the steric influence of L and the strain, which is induced on the TrpyPd^II unit.