鞭角华扁叶蜂自然种群生命表

鞭角华扁叶蜂Chinolydaflagellicornis（F．Smith）是危害柏木的主要害虫,近年来在长江沿岸柏木防护林区发生严重,造成灾害。为了解该虫的种群动态规律及影响虫口数量变动的致死原因,并为该虫的预测预报提供资料,笔者于1995～1996年在忠县、云阳两县对鞭角华扁叶蜂自然种群进行了观察,现将结果整理于后。1生命表的研制过程1．1生命表观察虫期的划分[1]：根据鞭角华扁鞭角华扁叶蜂平均生命表叶蜂的发育进度和生活习性,将整个世代划分为卵期,1、2、3、4～6龄幼虫期,预蛹期,蛹期和成虫期共8个发育阶段。l．2观察方法。于1995—1996…     

鞭角华扁叶蜂虫卵数模型研究

该研究在野外获得了鞭角华扁叶蜂虫卵数与生境因子海拔、胸径、树高、海拔、冠幅坡向的数据;内业利用Matlab7软件分别建立了鞭角华扁叶蜂虫卵数的全变量模型、逐步回归模型和主成分模型,三模型的复相关系数R~2分别为0.9204,0.91841和0.9289,均方误差RMSE分别为322.4069,331.7300和310.9550,从两个系数看,得出一致结论以主成分法拟合最佳.逐步回归模型只采用了两个因子即树高和冠幅,主成分法采用了前三个主成分量,其信息量达93.6359%,可代表原特征变量的大部分信息.     

鞭角华扁叶蜂幼虫期的呼吸代谢

报道了鞭角华扁叶蜂Chinolyda flagellicornis幼虫不同发育时期的耗氧量.试验表明,鞭角华扁叶蜂的耗氧量随着幼虫的生长发育而增加,在同一龄期内,耗氧量与虫体鲜重呈2次曲线相关;在不同的龄期之间,耗氧量则与虫体鲜重的0.8299次方成正比.在同一龄期内,幼虫的代谢速率呈抛物线状;在整个幼虫期随着龄期的增加而呈下降趋势.     

鞭角华扁叶峰幼虫期的呼吸代谢

报道了鞭角华扁叶蜂Chinolyda flagellicornis幼虫不同发育时期的耗氧量,试验表明,鞭角华扁叶蜂的耗氧量随着幼虫的生长发育而增加,在同一龄期内,耗氧量与虫体鲜重呈2次曲线相关;在不同的龄期之间,耗氧量则与虫体鲜重的0.8299次方成正比,在同一龄期内,幼虫的代谢速率呈抛物线状;在整个幼虫期随着龄期的增加而呈下降趋势。     

鞭角华扁叶蜂蜕皮甾类激素滴度的变化

用放射免疫分析法测定了鞭角华扁叶蜂Chinolyda flagellicornis末龄幼虫及滞育预蛹血淋巴中蜕皮甾类激素滴度。结果表明,末龄幼虫血淋巴中蜕皮甾类激素滴度在第2和4天各有一高峰;滞育预蛹血淋巴中保持一定滴度的蜕皮甾类激素,并随发育时期的不同有所波动;预蛹化蛹前一周血淋巴中蜕皮甾类激素滴度存在两个与变态相对应的峰值。表明鞭角华扁叶蜂的滞育与蜕皮甾类激素相关。     

茅莓叶挥发油化学成分的研究

利用气相色谱-质谱联用技术对中药茅莓叶的挥发油化学成分进行了研究,共鉴定出20种成分,其中主要成分为棕榈酸,反油酸,癸醛,壬醛,顺式-9-烯,十六酸,顺式-3-癸烯醇,硬脂酸,月桂酸,6,10,14-三甲基-2-十五酮,十七醇,羊腊酸。棕榈酸的含量最高,占挥发油成分总量的32.67%。     

冷蒿挥发性有机化合物主要成分分析及其地上部分结构研究

冷蒿(Artemisia frigida)挥发性有机化合物(volatile organic compounds, VOCs)具有特殊气味, 在植物受损伤时, 此气味会更加浓烈。该文通过对未损伤与损伤冷蒿VOCs成分分析、地上部分结构观察, 初步揭示了冷蒿VOCs释放与结构之间的关系。结果表明, 未损伤冷蒿VOCs主要含有22种化合物, 其主要成分是莰烯(14.27%)、(E)-乙酸-3-己烯酯(10.85%)、对-伞花烃(9.05%)、桉树脑(39.80%)、α-萜品醇(10.04%)、β-萜品醇(2.48%)、樟脑(5.66%)和(R)-(-)-对薄荷-1-烯-4-醇(3.84%)。损伤较未损伤冷蒿VOCs增加了12种物质, 其中相对含量大于1%的化合物分别为顺-3-己烯醛(1.15%)、2-己烯醛(1.34%)、顺-牻牛儿醇(2.66%)、冰片(4.47%)、(1R,4R)(+)-对-薄荷-2,8-二烯(9.15%)、乙酸冰片酯(1.37%)和4(14), 11-桉叶双烯(1.30%)。冷蒿叶片中栅栏组织发达, 叶柄内具有2-3处栅栏组织, 并且栅栏组织中都具有发达的气室, 同时气室与气孔相连。因此, 损伤较未损伤冷蒿VOCs种类和浓度增多的原因可能为: 冷蒿VOCs合成后大量储存于气室中, 当叶片损伤时, VOCs大量释放出来, 同时合成释放一些新的VOCs, 致使损伤冷蒿VOCs种类和浓度增加。     

鞭角华扁叶蜂幼虫的营养成分分析

采用现代分析技术手段对鞭角华扁叶蜂Chinolydaflagellicornis(F.Smith)幼虫的主要营养成分进行分析,结果表明其鲜虫浆的蛋白质、氨基酸、粗脂肪、糖类及灰分含量分别为17.1%,13.5%,6.7%,1.0%和1.5%,胆固醇含量为0.3mg/g;含有7种人体必需氨基酸,其必需氨基酸占总氨基酸含量的43.0%,必需氨基酸与非必需氨基酸含量的比值为75.3%,第一限制性氨基酸为含硫氨基酸,即蛋氨酸和胱氨酸;同时,其不饱和脂肪酸与必需脂肪酸分别占总脂肪的61.3%和24.3%,特别是油酸和亚麻酸含量较高,分别达37.0%和18.4%;此外,还含有K,Ca,Mg,Fe,Zn,Cu,Mn等多种矿物质和微量元素。最后在分析其营养价值的基础上,对鞭角华扁叶蜂幼虫的开发利用价值进行了评价。     

SDE-GC-MS法分析三种虫生真菌菌丝中挥发性成分

采用同时蒸馏萃取-气相色谱质谱联用（SDE-GC-MS）的方法分析了蝉拟青霉、拟细羽束梗孢、根足被毛孢菌丝的挥发性成分,从中分别鉴定出44、28和19种化合物,它们主要为萜类化合物、芳香族化合物、醇类、烷烃类、酯类和醛类。成分比较发现,3种虫生真菌挥发性物质中有3种主要共有成分,分别为丁羟基甲苯、1-辛烯-3-醇、苯乙醛。除共有成分外,它们各自都有大量特有成分,其中蝉拟青霉主要有5-甲基-2-呋喃-乙酸酯、反式-2,4-癸二烯醛、长叶烯等;拟细羽束梗孢主要有5-羟基-2-癸烯酸-δ-内酯、2,4-二甲基-恶唑、苯酚、β-榄香烯等;根足被毛孢主要有3,4,5-三甲基-苯甲醛、1,3-二甲基-3,4,5,6-四氢化-2(1H)嘧啶、顺式-2-羟基-1-（羟甲基）-9-十八碳一烯酸乙酯。     

广聚萤叶甲取食对豚草挥发物组分的影响

植物在遭受植食性昆虫为害后,会系统性地释放虫害诱导挥发物(HIPVs).为探明广聚萤叶甲取食对豚草挥发物组分的影响,本研究采用动态顶空吸附法和气相色谱-质谱联用仪(GC-MS),收集并分析了豚草在受机械损伤和受广聚萤叶甲取食损伤前后挥发物组分及相对含量的变化.结果表明,豚草健康植株与损伤植株的挥发物组分和相对含量具有明显的差异.与健康植株相比,受机械损伤后的豚草挥发物中新出现了乙酸芳樟酯、桉树醇、十二醛、γ-木罗烯、植物醇、β-波旁烯,这些化合物在受损后立即释放,表明它们是组成型豚草挥发性有机化合物(VOCs);受取食损伤后,挥发物中大根香叶烯D的相对含量显著增加,表明大根香叶烯D为诱发型VOCs;而较于健康植株和机械损伤植株,取食损伤后的豚草VOCs中增加了桧烯、辛醛、β-罗勒烯、香茅醇,表明这些化合物为HIPVs.此外,机械损伤与取食损伤对豚草VOCs组分的影响有所不同.受机械损伤后,挥发物的种类减少后(损伤后第3天)很快又恢复到健康水平,而受取食损伤后,VOCs的种类逐渐减少(损伤后3d内).受损后不同时期挥发物的种类和相对含量亦有显著差异.受损后的早期(1 d),释放的多为一些豚草绿叶性物质,而在后期有一些诱导物释放.本研究结果为利用豚草VOCs和HIPVs组分提高广聚萤叶甲对豚草的防控效果奠定了重要基础.     

嘉陵江流域南充金城山森林群落结构特征分析

在采用样方法野外调查的基础上,进行组平均聚类,运用“空间序列代替时间序列”的方法,对嘉陵江流域南充金城山国家森林公园的森林群落特征进行了研究。将其划分为8个群落类型,并分别论述了各群落的结构特征,绘制了种群的年龄结构和存活曲线图。由种群的大小级结构动态和种群的存活曲线分析了各优势种群的结构格局,发现柏木林、杉木麻栎林种群为下降种群,马尾松林、马尾松川灰木林、川灰木山胡椒林种群为稳定种群,柏木白栎林、马尾松柏木林、麻栎白栎林种群为增长种群。生境条件和人为干扰是影响种群年龄结构和动态的重要因素。因此,对金城山国家森林公园的森林群落要加强保护、减少人为干扰和加强抚育管理。     

Evaluation of the composition and fumigant toxicity against Plodia interpunctella of essential oils from Ajania potaninii and Ajania fruticulosa

Indian meal moth, Plodia interpunctella (Lepidoptera: Pyralidae), is a worldwide omnivorous pest. It is the primary insect pest in many economically important stored crops. The insecticidal activity of essential oils (EOs) extracted from Ajania potaninii and Ajania fruticulosa were evaluated against Plodia interpunctella. EOs obtained by hydro-distillation were analyzed by GC–MS. Fumigant toxicity testing indicated that both EOs and their main components were toxic to P. interpunctella adults. 1,8-Cineole exhibited the strongest activity, having an LC₅₀ of 0.86 mg/L air and being twice as active as camphor. Myrtenol was also strongly toxic to P. interpunctella adults (LC₅₀ 0.99 mg/L air), while camphor, verbenol, borneol, and the two complete EOs exhibited lower toxicity. None of the EOs or main components exhibited significant toxicity against the larvae of P. interpunctella. This study provides evidence of the individual active substances accounting for the insecticidal activity of EOs from A. potaninii and A. fruticulosa. These EOs have potential as biological insecticides for controlling insect pest damage in stored crops.     

Priming of Production in Maize of Volatile Organic Defence Compounds by the Natural Plant Activator cis-Jasmone

cis-Jasmone (CJ) is a natural plant product that activates defence against herbivores in model and crop plants. In this study, we investigated whether CJ could prime defence in maize, Zea mays, against the leafhopper, Cicadulina storeyi, responsible for the transmission of maize streak virus (MSV). Priming occurs when a pre-treatment, in this case CJ, increases the potency and speed of a defence response upon subsequent attack on the plant. Here, we tested insect responses to plant volatile organic compounds (VOCs) using a Y-tube olfactometer bioassay. Our initial experiments showed that, in this system, there was no significant response of the herbivore to CJ itself and no difference in response to VOCs collected from unexposed plants compared to CJ exposed plants, both without insects. VOCs were then collected from C. storeyi-infested maize seedlings with and without CJ pre-treatment. The bioassay revealed a significant preference by this pest for VOCs from infested seedlings without the CJ pre-treatment. A timed series of VOC collections and bioassays showed that the effect was strongest in the first 22 h of insect infestation, i.e. before the insects had themselves induced a change in VOC emission. Chemical analysis showed that treatment of maize seedlings with CJ, followed by exposure to C. storeyi, led to a significant increase in emission of the defensive sesquiterpenes (E)-(1R,9S)-caryophyllene, (E)-α-bergamotene, (E)-β-farnesene and (E)-4,8-dimethyl-1,3,7-nonatriene, known to act as herbivore repellents. The chemical analysis explains the behavioural effects observed in the olfactometer, as the CJ treatment caused plants to emit a blend of VOCs comprising more of the repellent components in the first 22 h of insect infestation than control plants. The speed and potency of VOC emission was increased by the CJ pre-treatment. This is the first indication that CJ can prime plants for enhanced production of defensive VOCs antagonist towards herbivores.     

Volatile organic compounds released by maize following herbivory or insect extract application and communication between plants

To protect themselves from herbivory, plants have evolved an arsenal of physical and chemical defences and release a variety of volatile organic compounds (VOCs). By releasing these VOCs, a signalling plant can both reduce herbivory, sometimes by more than 90%, and also warn neighbouring plants about an attack. The aim of this study was to assess the influence of herbivory and insect extract application on VOC release by damaged/treated and nearby undamaged/untreated maize plants. We confirmed that European corn borer (Ostrinia nubilalis) larvae attack or larvae extract application induced maize VOC release. Greater amounts of (Z)‐3‐hexenal, (E)‐2‐hexenal, (Z)‐3‐hexen‐1‐ol, (E)‐2‐hexen‐1‐ol, β‐myrcene, (Z)‐3‐hexen‐1‐yl acetate, 1‐hexyl acetate, (Z)‐ocimene, linalool, benzyl acetate, methyl salicylate, indole, methyl anthranilate, geranyl acetate, β‐caryophyllene, (E)‐β‐farnesene and (Z)‐3‐hexenal, (Z)‐3‐hexen‐1‐ol, (Z)‐3‐hexen‐1‐yl acetate, (Z)‐ocimene, linalool, indole, methyl anthranilate, geranyl acetate, β‐caryophyllene and (E)‐β‐farnesene were released as a result of biotic stress after insect attack or insect extract application. The amounts of each VOC released were qualitatively and quantitatively distinct and dependent on time after biotic stress exposure. However, for all biotic stresses, significantly lower VOC induction was measured when leaves were damaged/treated for three days, as compared to seven days. Our work also demonstrated that undamaged/untreated neighbouring plants also release significant amounts of VOCs. This suggests that VOC emission by a damaged/treated plant stimulates VOC induction in nearby undamaged/untreated plants. However, the concentrations of all VOCs released by neighbouring undamaged/untreated maize plants were lower than those from damaged/treated plants and were negatively correlated with distance from a damaged/treated plant. Still, significant VOC induction occurred in undamaged/untreated plants even at 3 m distance from a damaged/infected plant. Our work suggests that maize plant protective defence responses (VOC emission) can be induced via application of European corn borer extracts.     

厚朴野生种与栽培种花不同部位香气成分分析

以厚朴野生种和栽培种苞片刚裂开的花苞为试材,采用固相微萃取和气相色谱—质谱(GC/MS)分析技术对其进行香气成分和相对含量的测定,比较分析了花朵不同部位香气成分的差异。结果表明：厚朴野生种共有39种香气成分,雌雄蕊中26种,花瓣中22种,栽培种中75种香气成分,雌雄蕊中49种,花瓣中54种。萜烯类是两种厚朴花苞中最重要的香气化合物,莰烯、罗勒烯异构体混合物、石竹烯、芳樟醇是野生种和栽培种中共有的相对含量较高的香气成分。厚朴野生种和栽培种间以及同种厚朴雌雄蕊与花瓣之间的香气成分的种类和相对含量差异显著。     

Effect of infestation with Callosobruchus maculatus on the GC/MS chemical constituents and minerals of cowpea seeds

Poor storage of cowpea seeds causes the infestation of store pests, and consequently, the quality of the seeds decreases in quantity and quality. Therefore, continuous detection of the infestation has become necessary. Cowpea is one of the most economically essential legumes in different world areas. Cowpea is severely damaged in the store by the cowpea storage pest, Callosobruchus maculatus (Fab.), and early detection of insect infestation is essential for implementing timely and effective pest management decisions to protect them.The effect of insect infestation with Callosobruchus maculatus on the chemical composition of cowpea seeds (Vigna unguiculata) and mineral content was studied. The volatile compounds were analyzed and identified by gas chromatography-mass spectrometry (GC–MS) for the raw (non-infested), cooked, infested, and cooked cowpea seeds and the adult insect of C. maculatus.GC–MS analysis results showed that six volatile compounds were identified from raw cowpea seeds and only three from cooked ones. (9,12- Octadecadienoic acid, methyl ester) was identified in cooked seeds but not detected in raw seeds. Eight volatile compounds were detected only in infested seeds with C. maculatus alone, and these compounds can be used for detecting C. maculatus in cowpea seeds. Two specific compounds, such as Stigmasterol, and Beta-Sitosterol, were detected in infested cooked cowpea seeds.In cowpea seeds, infestation caused a reduction in the concentration of Aluminum (Al) and Iron (Fe), while Manganese (Mn) increased either after or before the cooking. Without infestation, the cooking process alone decreased Al, Fe, and Mn concentrations.     

Olfactory response of four aphidophagous insects to aphid- and caterpillar-induced plant volatiles

Plants damaged by herbivores emit blends of volatile organic compounds (VOCs) that attract the herbivore’s natural enemies. Most work has focussed on systems involving one plant, one herbivore and one natural enemy, though, in nature, plants support multiple herbivores and multiple natural enemies of these herbivores. Our study aimed to understand how different aphid natural enemies respond to aphid-induced VOCs, and whether attraction of the natural enemies that responded to aphid-induced VOCs was altered by simultaneous damage by a chewing herbivore. We used a model system based on Brassica juncea (Brassicaceae), Myzus persicae (Hemiptera: Aphididae) and Plutella xylostella (Lepidoptera: Plutellidae). Ceraeochrysa cubana (Neuroptera: Chrysopidae) did not show preferences for any plant odour, while Cycloneda sanguinea (Coleoptera: Coccinellidae) responded to undamaged plants over air but not to aphid-damaged plants over undamaged plants. Therefore, no further tests were carried out with these two species. Chrysoperla externa (Neuroptera: Chrysopidae) preferred aphid-damaged plants, but not caterpillar-damaged plants, over undamaged plants, and preferred plants damaged by both herbivores over both undamaged plants and aphid-damaged plants. When tested for responses against undamaged plants, Aphidius colemani (Hymenoptera: Braconidae) preferred aphid-damaged plants but not plants damaged by caterpillars. Plants damaged by both herbivores attracted more parasitoids than undamaged plants, but not more than aphid-damaged plants. Thus, multiply damaged plants were equally attractive to A. colemani and more attractive to C. externa than aphid-damaged plants, while C. cubana and C. sanguinea did not respond to aphid-induced VOCs, highlighting how different natural enemies can have different responses to herbivore-damaged plants.     

酸枣叶对土壤水分的生理生化响应

酸枣(Ziziphus jujuba var.spinosa)分布广、适应性强、极耐旱,是研究植物响应干旱气候的优良试验材料。通过覆膜技术控制酸枣根系附近土壤水分含量,研究了不同土壤水分条件对酸枣叶片组织含水量、叶绿素含量、丙二醛、可溶性糖含量等生理生化指标的影响,以期探明酸枣适应干旱的生理机制。结果显示：随着土壤含水量的降低,处理组酸枣叶片的相对含水量与绝对含水量均降低,但都保持在较高水平,与对照相比,差异显著（p<0.05）;自然饱和亏呈下降趋势且维持在较低水平,较对照差异均显著（p<0.05）;随着土壤水分的减少,处理组酸枣叶片较对照组组织水势和渗透势减小（p<0.05）,较对照差异显著（p<0.05）,吸水能力提高;处理组酸枣叶片的叶绿体色素含量随土壤干旱程度的加深,均表现为低于对照且逐渐减少（p<0.05）;随着处理时间的延长,处理组与对照组相比,电导率随之增大,MDA含量也随之升高,质膜受到损伤;处理组酸枣叶片中渗透调节物质可溶性糖含量和游离脯氨酸含量均有不同程度的增加,平均增幅为1.29、1.5倍。结果表明,酸枣叶片在不同的土壤水分条件下,具有积极的生理响应方式,适应性强,具有较强的抗旱耐旱能力。     

喜树与南方红豆杉混交群落生活史型谱特征

研究了不同生境条件下喜树和南方红豆杉混交群落中喜树和南方红豆杉的生活史型谱特征。结果表明,喜树和南方红豆杉在S生活史型得分和比例均为0。喜树和南方红豆杉生活史型V主成分得分均以山地2最高,而纯林的生活史型V主成分得分最低,C也表现为山地2最高,而纯林最低。喜树种群的生活史型比例按照从山地、坡地、平地、纯林排序,V型比例逐渐上升而C型比例逐渐下降的趋势,这就构成了混交群落中喜树种群的生活史型谱。南方红豆杉种群的生活史型谱特征,主要表现为山地2和坡地V型比例最小,而C型比例最大,纯林种植中V型比例较高,而以纯林1的V型比例最高,C型比例最小。     

Z-3-Hexenylacetate emissions induced by the endophyte Epichloë occultans at different levels of defoliation during the host plant's life cycle

Vertically transmitted fungal endophytes are common defensive symbionts of cool-season grasses. Protection against herbivores has been generally associated with alkaloids produced in the grass-endophyte symbiosis. However, many other changes occur in host metabolism like the release of VOCs. We aimed at characterizing the profile of volatile organic compounds (VOCs) induced by simultaneous fungal endophyte symbiosis and defoliation during the entire life cycle of the annual host grass and the asexual symbiont. We designed an outdoor factorial experiment with plots dominated by intact and damaged Lolium multiflorum plants with high and low infection levels with Epichloë occultans. After exploring the entire VOC profile, the green leaf volatile (Z)-3-hexenyl acetate (Z3-HAC) was found as the main compound emitted by the plants under field conditions. While in low-infected patches there were no differences in volatile emission during the plant life cycle, highly infected patches emitted more Z3-HAC in seedling and vegetative phases than in the reproductive phase. The role of Z3-HAC provided by symbiotic to neighbouring non-symbiotic plants in the associational protection against herbivores and fungal pathogens is discussed.