光对入侵性植物黄顶菊种子萌发及植株生长的影响

入侵性杂草黄顶菊原产南美,2003年在我国河北省衡水湖首次报道。采用室内控制试验,对光与黄顶菊种子发芽及植株生长的关系进行了研究。结果表明：黄顶菊种子属光敏型,种子需要光刺激才能发芽。但其萌发对光强要求不严,1 000 lx光照强度30 ℃培养6、12 h和24 h转入暗培养,5 d后黄顶菊种子发芽率分别为67.0%、88.0%和95.8%。黄顶菊种子出苗与光照关系密切,播种在土壤表面、0.5 cm和1 cm深土层的种子出苗率分别为96.0%、8.0%和0。随光照强度减弱,植株的生物量及繁殖力显著降低。黄顶菊在35%自然光强下生长时其生物量、结实数比自然光强下分别降低55.0%和55.6%。上述结果为预测黄顶菊的适生区域及制订有效的防除策略提供了科学依据。     

基于年龄-阶段两性生命表的不同寄主对马铃薯块茎蛾生长发育和繁殖力的影响

为生态调控马铃薯块茎蛾Phthorimaea operculella,在室内测定取食马铃薯和烟草后马铃薯块茎蛾的各生长发育指标,并利用年龄-阶段两性生命表计算取食这2种植物后马铃薯块茎蛾的存活率、繁殖力、寿命期望、繁殖值和种群参数,并分析不同寄主之间各参数的差异。结果表明,取食烟草的马铃薯块茎蛾卵发育历期、幼虫发育历期、蛹发育历期、雌成虫寿命和雄成虫寿命分别为5.0、18.6、5.7、41.2和40.9 d,均显著大于取食马铃薯的马铃薯块茎蛾(分别为4.1、16.7、3.6、37.2和36.7 d),取食马铃薯的马铃薯块茎蛾的每日单雌产卵量、内禀增长率、周限增长率和净增殖率分别为130.2粒、0.138 d-1、1.15 d-1和49.5,均显著高于取食马铃薯的马铃薯块茎蛾(分别为49.1粒、0.086 d-1、1.09 d-1和17.5);取食马铃薯的马铃薯块茎蛾幼虫、蛹、新孵化个体到雌成虫和新孵化个体到雄成虫的存活率分别为93.4%、63.0%、38.0%和45.0%,也高于取食烟草的马铃薯块茎蛾(分别为65.6%、59.0%、26.0%和28.0%);取食马铃薯的马铃薯块茎蛾其平均世代周期为28.3 d,显著短于取食烟草的马铃薯块茎蛾(33.2 d)。表明马铃薯块茎蛾取食马铃薯和烟草后均能正常生长发育和繁殖,但马铃薯更适合马铃薯块茎蛾生长。     

黄顶菊种子休眠与种子寿命研究

黄顶菊是一种新近传入我国的入侵植物。初步研究黄顶菊种子休眠和种子寿命特性发现,黄顶菊种子不具有原生休眠,但需要一定的时间完成其后熟阶段。室温储藏下4年后,黄顶菊种子仍保持很高的萌发率,说明黄顶菊种子的寿命较长,但长时间的冷冻(-18℃)和自然条件下深埋(10 cm土层)会显著缩短黄顶菊种子的寿命。     

田间黄顶菊种子成熟进度研究

河北地区8月中旬黄顶菊可产生具有萌发力的种子.9月上、中旬黄顶菊开花3～5 d即可产生具萌发力的种子.此时产生的种子成熟进度最快、所需日度最少.9月中旬至10月初,黄顶菊种子成熟度最高,萌发率达94％以上.10月黄顶菊进入末花期,开花20 d内完成种子成熟过程,但种子萌发率低于20％.9月25日前开花的黄顶菊,种子达到50％发芽率所需有效积温随开花始期递减.黄顶菊植株初花期是对其防治的最晚时期,7月底至8月初为河北地区黄顶菊最晚防治适期.     

入侵害虫草地贪夜蛾取食七种食物的种群生命表

为阐明入侵害虫草地贪夜蛾Spodoptera frugiperda对我国不同农作物的适应性,利用年龄-阶段两性种群生命表技术研究取食玉米粒以及玉米、花生、棉花、大豆、高粱和谷子叶片等7种不同食物对草地贪夜蛾生长发育与繁殖的影响。结果表明,不同食物显著影响草地贪夜蛾种群。整个成虫前期从长到短依次为取食棉花叶>取食大豆叶>取食高粱叶>取食花生叶>取食谷子叶>取食玉米叶>取食玉米粒,取食玉米粒要比取食棉花叶的时间缩短27.95 d。雌雄成虫寿命均以取食玉米粒和高粱叶的最长,以取食玉米叶的较短,且取食棉花叶的雄成虫寿命仅有3.00 d。产卵量以取食玉米粒的最多,为619.27粒,是取食其他食物的6.00倍～61.25倍。取食玉米叶的草地贪夜蛾初孵幼虫个体完成幼虫、蛹和成虫阶段的概率均较高,分别为95.38%、78.46%和78.46%,而取食棉花叶的最低,分别为37.29%、20.34%和20.34%。草地贪夜蛾取食玉米粒的净增值率、内禀增长率、周限增长率均最高,分别为105.59、0.12 d-1、1.13 d-1,平均世代周期最短,为36.91 d,而取...     

有害杂草黄顶菊在河北衡水的入侵途径调查

本文通过调查,将黄顶菊在我国的发生时间由2001年提前到1996年,分析了黄顶菊可能的传入途径：随船舶丢弃的砂子等压舱物、动物皮毛等途径入侵,随粮谷贸易传入的可能性极小.     

基于两性生命表评价取食柑橘木虱对六斑月瓢虫和龟纹瓢虫生长发育及种群的影响

为有效防控重要害虫柑橘木虱Diaphorina citri,在实验室条件下测定取食柑橘木虱后六斑月瓢虫Cheilomenes sexmaculata和龟纹瓢虫Propylea japonica各虫态的发育历期,利用构建的年龄-阶段两性生命表对取食柑橘木虱后六斑月瓢虫、龟纹瓢虫生长发育及其种群参数进行研究。结果显示,取食柑橘木虱后六斑月瓢虫羽化前的发育历期为14.80 d,显著长于取食柑橘木虱后龟纹瓢虫的14.41 d;取食柑橘木虱后六斑月瓢虫和龟纹瓢虫产卵期分别为15.88 d和10.23 d,前者显著长于后者;取食柑橘木虱后六斑月瓢虫净增殖率、内禀增长率和周限增长率分别为25.48、0.10 d-1和1.10 d-1,取食柑橘木虱后龟纹瓢虫净增殖率、内禀增长率和周限增长率分别为14.13、0.06 d-1和1.06 d-1,均低于取食柑橘木虱后六斑月瓢虫;取食柑橘木虱后六斑月瓢虫和龟纹瓢虫的平均世代周期分别为33.87 d和44.95 d,前者显著短于后者。表明取食柑橘木虱后六斑月瓢虫和龟纹瓢虫均能完成整个世代,且六斑月瓢虫种群增长优于龟纹瓢虫,可大规模繁殖六斑月瓢虫,可用于柑橘木虱...     

取食不同食物对日本通草蛉生长发育、繁殖和飞行能力的影响

本文研究了日本通草蛉Chrysoperla nipponensis幼虫取食棉铃虫Helicoverpa armigera、小地老虎Agrotisipsilon、甜菜夜蛾Spodoptera exigua、斜纹夜蛾Spodoptera litura 4种鳞翅目害虫卵和棉蚜Aphis gossypii共5种食物时的生长发育、繁殖和飞行能力。结果表明：幼虫取食棉铃虫卵时发育历期最长（12.95 d）、蛹期最短（9.69 d）,取食棉蚜时发育历期最短（10.28 d）、蛹期最长（10.39 d）;幼虫食物对蛹重、成虫羽化率、产卵前期、产卵量和寿命均无显著影响（P〉0.05）。飞行能力测试中,幼虫食物显著影响成虫的累计飞行时间和平均飞行速度,而对成虫累计飞行距离则无显著影响;幼虫取食棉铃虫卵时成虫累计飞行时间最长（13.58 h）、飞行超过10 h的个体占60%,平均飞行速度最小（0.49 km h 1）、所有个体飞行速度均小于1.0 km h 1;取食棉蚜时成虫累计飞行时间最短（9.38 h）、飞行超过10 h的个体仅占36.85%,平均飞行速度最大（0.75 km h 1）、21.05%个体飞行速度大于1.0 km h 1。结果说明,幼虫食物是影响日本通草蛉个体发育和种群动态的重要因素之一。     

地红蝽特殊取食行为及其偏好性

为探究地红蝽Pyrrhocoris tibialis St?l的特殊取食行为及其取食选择性，通过在室内外观测并全程记录地红蝽的取食行为，研究其对12种植物种子以及不同部位和不同成熟度苘麻种子的取食偏好性。结果表明，地红蝽室外取食行为包括寻水、吸水、清理、离开、搜寻、摩擦、刺探、插入、携带、攀爬、取食、静止和离开共13个过程；在室内有92%的地红蝽具先吸水后取食的行为，8%只进行吸水行为。地红蝽对苘麻种子的取食偏好性最高，选择率为41.71%，取食时长为77.30 min，刺探次数为3.44次，均显著高于其余植物种子；地红蝽对苘麻种子种皮厚度最薄（96.12μm）的左肩部位取食选择率最高，为28.93%，显著高于其他部位；对成熟度最高的深色苘麻种子取食偏好性最高，选择率为42.00%，取食时长为182.94 min，刺探次数为6.44次，高于次深色和浅色苘麻种子。表明地红蝽取食行为是吸水-携带种子攀爬-取食的特殊取食行为，且偏好取食苘麻种子并对种皮厚度最薄部位和成熟度最高苘麻种子的取食偏好性强。     

补充外源营养对斜纹夜蛾侧沟茧蜂寿命和繁殖力的影响

本文研究了外源营养对斜纹夜蛾侧沟茧蜂Microplitis prodeniae Rao and Kurian寿命和繁殖力的影响及其日取食节律。研究结果表明,取食浓度为10%的混合糖液、葡萄糖、蔗糖、蜂蜜、果糖、清水和不饲喂后,斜纹夜蛾侧沟茧蜂的雌蜂寿命分别为14.67、11.22、11.03、10.00、9.58、4.67和3.65 d、雄蜂寿命分别为13.93、10.67、10.62、9.60、9.53、3.50和2.72d;取食混合糖液、葡萄糖、蔗糖、蜂蜜、果糖和清水后,雌蜂总产卵量分别为180.45、149.80、147.30、112.35、122.45和31.05粒,取食混合糖液处理组的寿命和总产卵量均显著高于其它处理。不论补充营养还是清水,该蜂的产卵都是先升高后下降。10%的混合糖液为最佳浓度。取食频率为1d吸食1次的寿命最长。该蜂分别在8:00-9:00和15:00-16:00出现取食高峰。     

天然油菜素内酯对五种牧草种子发芽和胚根下胚轴伸长的影响

用9个不同浓度的天然油菜素内酯溶液浸种处理5种牧草种子,观测其对种子发芽和胚根下胚轴伸长的影响。结果表明,0.01 mg/L浓度处理使苜蓿种子发芽率比对照提高了32.2%,发芽天数缩短了1.4 d;0.01mg/L处理使鲁梅克斯种子发芽率增加了27.8%,0.05 mg/L处理使其发芽天数提前了0.8 d;0.03 mg/L处理使普那菊苣种子发芽率提高了28.9%,发芽天数缩短了0.3 d;0.4 mg/L处理使串叶松香草种子发芽率增加了26.7%,发芽天数提前了1.2 d;0.03 mg/L处理使小冠花种子发芽率提高了23.3%,0.05 mg/L使其发芽天数缩短了0.9 d。0.05、0.07、0.03、0.4和0.03 mg/L处理对苜蓿、鲁梅克斯、普那菊苣、串叶松香草和小冠花胚根下胚轴伸长的促进效应最为明显。     

Recovery and germination of Prosopis juliflora (Sw.) DC seeds after ingestion by goats and cattle

Prosopis juliflora is a perennial shrub introduced in the 1980s to the Baringo District in central Kenya, and became highly invasive starting around the late 1990s. This period coincides with a shift of the composition of ruminant herds from formerly cattle to goats in this area. To assess the possible role of this shift in herd structure on P. juliflora spread, we conducted feeding trials and germination tests to determine the capacity of seeds to survive the passage through the intestinal tract of goats and cattle, comparing germination with chemically scarified and untreated seeds. Recovery of seeds eight days after ingestion was lower from goats (7%) than from cattle (15%) dung. Germination dynamics were similar for seeds that had been manually extracted from pods with those recovered after intestinal passage. Chemically scarified seeds germinated fastest and reached a germination rate of 100% within five days. While no apparent scarification effect was observed, the main contribution of endozoochorous dispersal of Prosopis seeds is their release from the enclosing pod segments, their dispersal away from the mother plant and possibly the provision of nutrients by the dung for their establishment and initial growth.     

Phenology and seed production of variegated thistle, Silybum marianum (L.) Gaertn., in Australia in relation to mechanical and biological control

Production of viable seeds occurred in immature capitula of Silybum marianum following simulated slashing and mowing. In the slashing treatment, capitula with 20 cm or less of stem attached produced viable seeds if cut off when at least half the florets were open, the proportion of viable seeds ranging from 0·3% in capitula at midanthesis to 12% in those at the end of anthesis. Following mowing, viable seeds were produced in full-sized buds which were close to anthesis and in capitula at any stage of anthesis at the time of plant cutting, the proportion increasing from 0·1% in capitula at the start of anthesis to 30% in those at the end. Within a capitulum, anthesis usually lasted five days in irrigated plants. Ripe seeds were released about 17 days later. Seed production averaged 190 seeds for the primary capitulum and 114 in others. In a flowering season starting in early November and lasting about two months, individual plants had the potential to produce an average of 55 capitula, representing an output of 6350 seeds per plant, of which 94% were viable. In view of the prolonged flowering season and the large seed output of S. marianum, it is argued that the restricted period of oviposition by the weevil Rhinocyllus conicus and the low density of larvae per capitulum might limit its impact as a biological control agent for this weed in Australia.     

Fate of endosulfan in rats and toxicological considerations of apolar metabolites

[¹⁴C]Endosulfan, α or β isomers separately, was administered to rats as a single oral dose and as a dietary supplement for 14 days. No appreciable differences were observed in the fate of the two isomers. Five days after the single dose, 75% of the dose had been voided in the feces and 13% in the urine. Of the total radiocarbon consumed in the diet after 14 days, 56% had been eliminated in the feces and 8% in the urine. Bile collection studies showed that up to 47% of a single oral dose was eliminated from the liver via this route; enterohepatic circulation was not apparent. Maximum [¹⁴C]endosulfan equivalents in body tissue occurred in the kidney and liver, 3 and 1 ppm, respectively, after 14 days of feeding 5 ppm of endosulfan. Apolar metabolites in the excreta and/or tissues were a minor portion of the total residues and consisted of the sulfate, diol, α-hydroxy ether, lactone, and ether derivatives of endosulfan. The sulfate was slightly more toxic to mice than endosulfan, while the other products were less toxic. Neither endosulfan nor its metabolites were active in the Salmonella mutagenicity test. Endosulfan in the diet of rats for 28 days at 50 ppm did not induce liver oxidase enzymes, alter liver or kidney weights, or influence the rate of weight gain of the animals.     

Enhanced excretion of DDT and metabolites in rats treated with trans,trans-muconate

The interactions between trans,trans-muconate and p,p′-DDT were examined. Male Wistar rats were injected intraperitoneally with 6.67 mg kg^?1 [¹⁴C]p,p′-DDT. Two hours later the experimental animals received orally a solution of sodium muconate (75 mg kg^?1, 0.3 ml) in physiological saline, pH 7.2; control animals received an equal volume of physiological saline. Treatment was repeated every 12 hr for 10 days. Sodium muconate does not modify urinary excretion of labeled compounds, yet it reduces body burden by accelerating the excretion rate of these compounds in rat feces. This action was observed only during the first 24 hr after the animals were exposed to p,p′-DDT.     

Comparison of extraction procedures and determination of the detection threshold for Clavibacter michiganensis ssp. michiganensis in tomato seeds

Several seed extraction procedures, used for detection of Clavibacter michiganensis ssp. michiganensis ( Cmm ) in naturally infected and artificially infested tomato seed lots were evaluated. Extraction methods that included grinding the seeds were significantly better at detecting the pathogen in three different seed lots than methods that used only soaking. The detection threshold of Cmm in relation to seed sample size was determined by adding naturally infected seeds into samples of three different sizes. Cmm was detected by agar plating assay, on three media (CNS, mSCM, D₂ANX), and by direct PCR from seeds and Bio-PCR (bacteria cultured on agar media prior to PCR). In samples of 10 000 seeds containing one infected seed, Cmm could be detected only by Bio-PCR and in only one replicate out of five. In samples containing five or 10 infected seeds per 10 000 seeds, three of five and five of five replicates, respectively, were detected by the three detection methods. In samples of 5000 seeds, one infected seed could be detected in all five replicates only after adding a concentration step. A high correlation ( R ² = 0·9448) between artificially infested seeds and the disease incidence was found. Seed lots infested with less than 58 colony-forming units (CFU) per g did not cause disease under glasshouse conditions, whereas lots with about 1000 CFU g⁻¹ caused disease in 78 plants out of 2000.     

辣椒种生镰刀菌及其病理学意义的研究

 采用吸水纸检验法,对北京地区22份辣椒(Capsicum annuum)种子样品的分析结果是:木贼镰刀菌(Fusarium equiseti)、串珠镰刀菌(F. moniliforme)、尖孢镰刀菌(F.oxysporum)、半裸镰刀菌(F. semitectum)和茄病镰刀菌(F. solani)是5种常见的辣椒种生镰刀菌,其平均带菌率分别为1.0%,2.6%,0.1%,0.8%和0.2%。经发芽试验观察,在自然带菌的情况下,木贼镰刀菌,串珠镰刀菌、尖孢镰刀菌、半裸镰刀菌和茄病镰刀菌能分别使种子发芽率降低98.6%,39.8%、62.1%、2.7%和52.1%。经土壤接种法进行致病性测定,除半裸镰刀菌对植株无明显致病性反应外,其它4种镰刀菌均能不同程度地引起植株枯萎和其它病理症状。     

Assessment of the differential response of weeds to soil solarization by two methods

The efficacy of solarization in weed control under field conditions of the United Arab Emirates was evaluated by two methods: on-farm weed assessment and a seed germination test. In the on-farm weed assessment method, the weed frequency, density, and dry weight were compared in the solarized and non-solarized plots that were cultivated with cabbage. Prior to solarization, the soil was artificially infested with the seeds of 10 weeds. Generally, the densities of seven species and dry weights of five species were significantly lower in the solarized plots as compared to the control. Launea mucronata , Capsella bursa-pastoris , and Echinochloa colona were very sensitive to solarization, as they did not appear in the solarized plots. However, Portulaca oleracea and Melilotus indica were not significantly affected by soil solarization. In the second method, the germination was assessed for the seeds of four weedy species buried at three depths for different durations of solarization. The results confirmed the great sensitivity of L. mucronata and C. bursa-pastoris seeds to solarization, as all had not germinated after 15 days of solarization, even at the 15 cm depth. The seeds of E. colona , however, were less sensitive after 15 days of solarization, especially at 7.5 cm and 15 cm, respectively. The seed germination method confirmed the resistance of the P. oleracea seeds to solarization. The results emphasized the importance of the germination test to provide accurate predictions about the spatial and temporal changes of the soil seed bank in solarized farms. This would help to determine the optimal duration of solarization in each farm, depending on the kind of weeds infesting the farm.     

亚麻开花结实特性及籽粒干物质积累规律研究

选用具有一定代表性的4个油纤兼用型品种(系)和1个纤用型品种(系),从始花期开始,标记每天开的花,每5天为一期,标记三期,其余所有的花归为第四期。开花5天后采收果粒,测定不同时期、不同部位籽粒干物质积累量,利用logistic生长曲线方程对亚麻不同部位籽粒干物质积累进行了分析,结果表明:纤维型亚麻中部果实的籽粒较重,每果粒数较多,基部的次之,上部最轻;而兼用型亚麻的果粒数,粒重,结实率都由基部向上依次降低。单株产量中,均以中部籽粒所占比重最大。籽粒干物质积累量与平均积累速率,最大积累速率,快增期积累速率呈正相关。在所有的品种(系)中,快增期的增长速率显著高于渐增期和缓增期,不同部位籽粒的增重不同,兼用型亚麻基部籽粒增长速率低,持续时间长,干物质积累多,上部籽粒增长速率高,但持续时间短,籽粒轻,而纤用型的虽表现出相同趋势,但不同部位间差异较小。     

油菜田遏蓝菜发生规律与化学防除

试验明确,青海湟中地区遏蓝菜全生育期约为115d,出苗高峰期为5月上旬至中旬。种子发芽出苗最适土壤深度为1.0～3.0cm。花期约34d,果期约20d,单株结籽量平均690粒。种子有休眠习性,室外埋入土层8d萌发率为1.5％。遏蓝菜与油菜竞争危害表现在油菜全生育期,植株含氮、磷、钾量比油菜高2.3％～225.0％。遏蓝菜发生量与油菜籽产量呈极显著负相关关系,回归方程为y=203.15-0.53x。采用3种除草剂及其混剂对遏蓝菜的防除效果均在90％以上,油菜籽增产显著。