几种五倍子蚜虫的生活周期型研究

于1983—1990年在贵州五倍子产区对五倍子致瘿蚜—角倍蚜 Schlechtendalia chinensis、红小铁枣蚜Meitenaphis elongallis、蛋铁倍蚜 Kaburagia ovogallis、倍花蚜 Nurudea shirii、倍蛋蚜 S.Walker 的生活周期研究发现,在自然状况下,角倍蚜属于异寄主全周期型;其他几种倍蚜属于异寄主全周期与同寄主不全周期并行的复迁式生活周期型。此结论突破了我国有关学者提出的五倍子蚜虫均属异寄主全周期型的观点.并论证了生活周期型与五倍子产量的关系以及五倍子的发展战略问题。提出1.角倍的总体自然产量明显优于其他倍子的主要原因是:角倍蚜在藓类寄主上仅有性母世代,春季必须迁往挂倍寄主上产生两性世代,并营瘿成倍;而其他倍蚜在藓类寄主上发生侨蚜和性母两个世代,春季仅有部份侨蚜产生的性母迁往挂倍寄主,营瘿成倍。即,在挂倍寄主上倍蚜种群的总体数量,异寄主全周期型的倍蚜占有明显的优势,也反映为倍子产量的优势。2.根据各地的情况,在选择五倍子品种发展生产时,应首先考虑致瘿蚜生活周期型为异寄主全周期型的或占优势的五倍子种类。     

倍蛋蚜生活史及生物学习性研究初报

倍蛋蚜(Schlechtendalia peitan Tsai et Tang)是同翅目瘿绵蚜科倍蚜属中的一种倍蚜虫,主要分布于贵州、四川、云南、湖北等倍子产区。致瘿寄主盐肤木(Rhus chinensisMill),其寄生于盐肤木小叶基部侧脉上所形成的虫瘿为卵圆形,单宁含量64％,是五倍子中的优质品种。倍蛋蚜与角倍蚜(S.chinensis Bell.)有共同的致瘿寄主和部分共同的冬寄主,但与角倍蚜的致瘿部位不同。我们从1985～1987年在赤水、贵阳等产区,对倍蛋的生活史及生物学习性进行了观察,并找到了一种新的冬寄主。现将结果报导如下。     

蛋铁倍蚜生活史及其生物学特性初步研究

蛋铁倍蚜(Kaburagia ovogallis Tsai & Tang)是同翅目蚜科瘿绵蚜亚科铁倍蚜属的一种倍蚜虫。该蚜虫寄生在红麸杨小叶上形成的蛋铁倍,个体大,单宁酸含量高,品质优,是一种很有利用价值的倍子品种。广泛分布于贵州、四川、湖南、湖北、陕西、云南等五倍子产区,颇受国外专家所注重,但迄今尚未找到该蚜虫的越冬寄主,也无该蚜虫的生活史及     

虫瘿组织中肚倍蚜唾液蛋白的提取和鉴定

[目的]唾液是蚜虫与寄主植物相互作用的重要媒介,是诱导植物形成虫瘿的关键因子,对瘿蚜唾液成分的研究,不仅有助于揭示虫瘿形成机理,还可为刺吸式昆虫与寄主植物的协同进化研究提供依据。由于蚜虫唾液的提取和浓缩难度很大,到目前为止仅对少数种类进行过研究。[方法]以五倍子蚜的重要种类肚倍蚜指名亚种在青麸杨上形成的虫瘿为材料,根据虫瘿组织的结构特点,建立了从虫瘿组织中提取、浓缩、液质联用分析鉴定唾液蛋白的方法。[结果]应用超滤膜浓缩法和冷冻干燥法处理样品,经LC-MS/MS分析,真空冷冻干燥法浓缩样品的质谱图上有蛋白质峰,成功鉴定出肚倍蚜注入虫瘿组织中的部分唾液蛋白,分子量介于30.9～157.6 kDa,匹配的肽段数为1～4条,编码氨基酸长度为277～1 421。以豌豆蚜蛋白数据库为参考鉴定出5种蛋白(ACYPI 002474、ACYPI 006969、ACYPI 006711、ACYPI 007671、ACYPI 003311),分别为松脂蛋白、肌动蛋白、延伸因子蛋白、组蛋白和黏合连接蛋白。以拟南芥蛋白数据库为参考鉴定出7种蛋白(Q9FJY0、Q56Y48、P19366、P21238、Q9FFR3、Q9LTX9、O03042),分别为跨膜蛋白、ATP合成蛋白、伴侣蛋白、热激蛋白和磷酸羧化酶蛋白等。[结论]本研究应用LC-MS/MS方法从虫瘿组织中鉴定出12种蛋白,其中编号为ACYPI 006711的为延伸因子蛋白,在角倍蚜的唾液和唾液腺中被鉴定到;编号为ACYPI006969的为Actin蛋白,在角倍蚜唾液腺中也被鉴定到。由此可以判断,从肚倍蚜虫瘿组织中鉴定的蛋白有很大的可能来自于肚倍蚜唾液,这也为进一步研究虫瘿内唾液蛋白的功能提供了依据。     

应用快中子处理角倍蚜对后代生育及产结倍作用的初步研究

五倍子蚜虫的瘿外世代死亡率较高,影响五倍子产量的提高.本文报道了1987～1988年应用快中子辐照角倍好的试验结果,倍蚜能够完成生活周期,减少越冬死亡数,提高春迁蚜的羽化率,增加结倍数.辐照剂量为10~(16)通量的处理组,增产率最高,达108.3%.     

五倍子高效栽培技术——夏寄主建园技术

五倍子是瘿绵蚜科Pemphigidae蚜虫寄生漆树科Anacardiaceae盐肤木属树种的复叶主轴、叶翅和小叶上形成的一类虫瘿,主要成分为五倍子单宁,具有敛肺、降火、涩肠、止血等作用.中国是五倍子主产国,四川、贵州、湖北、湖南、陕西和云南6省产量约占世界总产量的75％.我国科技工作者对五倍子单宁及其应用,倍蚜及其冬夏寄主种类,倍蚜生物、生态学习性等进行了较详细地研究.倍蚜—夏寄主(盐肤木)—冬寄主(苔藓)是发展五倍子生产的"三要素",五倍子种类具有不同的地域性,不同的倍类寄主不同.本文所述五倍子是指角倍蚜虫寄生在盐肤木上所形成的虫瘿(角倍).五倍子资源利用主要以野生资源为主,传统生产中利用野生倍林进行五倍子生产具有单产低、大小年现象明显、劳动强度大、经济效益低下的缺点.在生产实践中,对倍烟(粮、药、菜)间作、野生倍林改造栽培模式建立高产夏寄主倍林、人工培养苔藓、倍蚜虫等技术措施进行了探索,取得了烟倍大面积间作造林2年产量达到了121.3 kg/666.7 m2的新记录.现将高效栽培技术总结如下.     

角倍蚜种群动态的研究

本文通过1988—1990年的研究,找出了角倍蚜在瘿外、瘿内阶段及春季迁飞期的种群消涨规律和影响因子.给出了角倍蚜瘿外阶段的种群生命表,性母蚜在湿地匐灯藓上的种群成活曲线,角倍蚜在瘿内阶段的种群增长曲线,以及春季迁飞期到产生致瘿干母时,春迁蚜、性蚜的损失率.     

五倍子蚜虫寄主植物矿质营养元素含量分析

对五倍子和倍蚜虫冬、夏寄主植物及其林地土壤样品的Ｐ、Ｋ、Ｃａ等８种矿质营养元素含量进行了测定分析。结果表明：寄主植物对土壤矿质营养的吸收难以适应和满足倍瘿（蚜）对其营养利用的需求。如欲维持和协调五倍子产结体系中矿质营养的合理比例与供需平衡，则应采取适当的人为措施向该体系中补施一定的营养元素。     

新发现六种五倍子蚜虫的冬寄主

五倍子蚜虫是我国重要的经济昆虫之一。该蚜虫一生必需在夏寄主即(结倍寄主和冬寄主)上转换寄生才能完成全部生活周期。而在冬寄主上繁殖生存的数量是确定倍子产结量的基础,是倍林增产的关键因素。目前已知夏寄主盐肤木、红肤杨、青肤杨的13种倍蚜虫中只报导了角倍蚜的冬寄主为7种提灯藓,肚倍蚜为佃技赤齿藓。进一步弄清各种倍蚜的冬寄主种类在倍蚜虫繁殖生产上具有十分重要的意义。1982—1984年我们在四川主要产倍林区采集多种倍蚜和带虫越冬藓类,通过接种试验和不同寄主上产生性母成蚜的形态鉴定,新确定了14种藓类为6种倍蚜虫的冬寄主,其中钝叶提灯藓和大叶提灯藓为角倍蚜的新寄主,其余12种为其他五倍子蚜虫首次肯定的冬寄主这些倍蚜虫及其冬寄主种类是:     

五倍子培殖技术要点

五倍子系瘿绵蚜科Pemphigideae五节根蚜亚科Fordinae的五倍子蚜虫。寄生于漆树科盐肤木Rhuschinensis Mill.(R.semialata Murr)、滨盐肤木R.chi-nensis Var roxburghii.Rehd.红麸杨R.puujabensisstew.Varsiuica (Die Is)Rehd.青麸杨R.PotauiniiMaxin以及黄连木Pistacia chinensis Bge的翅叶、小叶上形成虫瘿的总称。 五倍子含单宁酸、鞣花酸、双没食子酸、叶绿素和褐色酒精浸提物以及树胶、维生素、木质系、糖、蛋白质、无机盐等化学成份。其工业制品广泛用于医药、食品、纺织、化工、航天、环保、石油、采矿、冶炼、机械、感     

Improving the evaluation of multiple-dowel-type connection strength

Our study focuses on predicting the ultimate short-term load carrying capacity of timber-to-timber connections with dowel-type fasteners. The wide range of possible configurations in practice makes the resolution of these values by tests unrealistic. Moreover, different current regulations do not consider some specific failure mechanisms. In many countries, the reduction of resistance involved by this phenomenon is taken into account by considering an effective number of dowels (n_ef) smaller than the actual number of dowels (n) in the connection. However, these different regulations disagree on the values of n_ef and on other points (spacing, partial coefficient of security, formulas). These discrepancies in design rules invite the fundamental research on this topic and, therefore, new methods are sought in order to estimate the load carrying capacities of the connections. In the light of these, our approach consists of predicting the load carrying capacity with the neural network numerical tool. The results obtained by this analysis tool are satisfactory, although the model remains complex. Subsequently, we focus on the simplification of this numerical model with classical regression techniques in order to implement it in a design code.     

<Emphasis Type="Italic">Ophiostoma</Emphasis> species associated with bark beetles infesting three <Emphasis Type="Italic">Abies</Emphasis> species in Nikko,Japan

Ophiostoma species were isolated from bark beetles and Abies mariesii, A. veitchii and A. homolepis attacked by the beetles in Nikko, Tochigi, central Honshu, Japan. One to two Ophiostoma species were frequently isolated from each species of bark beetle. Ophiostoma subalpinum was the most common associate of Cryphalus montanus. Ophiostoma sp. B as well as O. subalpinum was a common fungus associated with Polygraphus proximus. Ophiostoma europhioides was isolated from Dryocoetes hectographus and D. autographus as one of the common associates. Ophiostoma sp. J and Ophiostoma sp. S were frequently isolated from D. autographus and D. striatus, respectively. These fungi seem to have specific relationships with particular bark beetles. Ophiostoma sp. B, Ophiostoma sp. J and Ophiostoma sp. S have unique morphological characteristics and appear to be new species. Five trees of A. veitchii, approximately 43 years old, were inoculated with five Ophiostoma species to assess the relative virulence of the fungi. Ophiostoma subalpinum, Ophiostoma sp. B, and O. europhioides had relatively higher virulence than the other species studied.     

Parasitic Ichneumonoidea on the horse chestnut leaf miner, Cameraria ohridella (Lepidoptera: Gracillariidae) in Slovakia

Parasitic Hymenoptera from the suprafamily Ichneumonoidea attacking the horse chestnut leafminer Cameraria ohridella Deschka & Dimic (Lepidoptera: Gracillariidae) were studied in southwest Slovakia during 2000 and 2001. The search for such species resulted in the determination of eight ichneumonid species, Gelis agilis (Fabricius), Itoplectis alternans (Gravenhorst), I. clavicornis (Thompson), I. maculator (Fabricius), Scambus annulatus (Kiss), S. brevicornis (Gravenhorst), Zatypota percontatoria (Müller), Adelognathus sp. and a braconid Colastes braconius Haliday. The most abundant species was S. annulatus. All these species recorded are polyphagous and often facultative hyperparasitoids, except C. braconius, which departs from this norm in not being hyperparasitic. The presence of more diversified native parasitoids and hyperparasitoids from the Ichneumonoidea predicate a slow successive adaptation of the parasitoid fauna to the invasive host, Cameraria ohridella.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Rehabilitation of diseased cacao fields in Peru through shade regulation and timing of biocontrol measures

The objective of this case study was to test the effectiveness of biocontrol for the rehabilitation of abandoned, diseased (moniliasis, witches' broom and black pod) cocoa and to develop testable hypotheses regarding the effect of shade and biocontrol timing. Three trial fields differed in their shade regimes. Biocontrol was administered starting either at flowering or pod filling. Disease incidence and yield were compared with cultural control alone. Biocontrol reduced moniliasis from 49% to 25%, independent of the shading regime and application time. Witches' broom was most severe without shade and unaffected by biocontrol. No significant effects on black pod were observed. Although biocontrol increased percentage healthy fruit independent of shading and timing, only the shaded plot with biocontrol from flowering onwards responded with increased yield. Our hypothesis is: 'In the rehabilitation of abandoned cacao, only fields under sustainable shade management and early onset of biocontrol can realise their production potential.' This revised version was published online in June 2006 with corrections to the Cover Date.     

Trees and shrubs as sources of fodder in Australia

Experience with browse plants in Australia is briefly reviewed in terms of their forage value to animals, their economic value to the landholder and their ecological contribution to landscape stability. Of the cultivated species only two have achieved any degree of commercial acceptance (Leucaena leucocephala and Chamaecytisus palmensis). Both of these are of sufficiently high forage value to be used as the sole source of feed during seasonal periods of nutritional shortage. Both are also leguminous shrubs that establish readily from seed. It is suggested that a limitation in their present use is the reliance on stands of single species which leaves these grazing systems vulnerable to disease and insects. Grazing systems so far developed for high production and persistence of cultivated species involve short periods of intense grazing followed by long periods of recovery. Similar management may be necessary in the arid and semi-arid rangelands where palatable browse species are in decline.     

Populations of adult fungus gnats and shore flies in British Columbia container nurseries as related to nursery environment,and incidence of fungi on the insects

Adult fungus gnat and shore fly populations were monitored in four container nurseries near Victoria, British Columbia. In general, populations of both insects were larger in summer than in winter. Also, both insects were more abundant in the nursery with a plastic-covered, soil floor, which favored moisture accumulation and build up of algae, liverworts and mosses, than in nurseries with other types of floors such as cement. Results of fungus isolations revealed that gnats and flies both harbor the seedling pathogens Botrytis cinerea and species of Fusarium and Phoma, plus several non-pathogenic fungi. The results are discussed in relation to nursery sanitation practices, their effects on gnat and fly populations, and some possible roles of these insects in seedling disease epidemiology.     

Insecticidal activity of certain medicinal plants

The methanol extracts of eight species of medicinal plants were tested for insecticidal activity in third instar larvae of Egyptian cottonworm (Spodoptera littoralis). All extracts showed a certain degree of larval toxicity. The extracts of Ocimum basilicum, Origanum majorana and Salvia officinalis appeared to be highly toxic. The extracts significantly affected the growth indexes [relative growth rate (RGR), efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD)].     

A new norlignan from Taxodium ascendens

A new norlignan, (2R,3R,4S,5S)-2,4-bis(4-hydroxyphenyl)-3,5-dihydroxy-tetrahydropyran (1), together with 9 known compounds were isolated from the branches and leaves of Taxodium ascendens. Their structures were mainly determined on the basis of MS, IR, 1D and 2D NMR spectral evidences. Methanol extract showed inhibitory activity on carbonic anhydrase II with an IC₅₀ value of 4.27 µg/ml, acetone extract and methanol extract inhibited activity of cathepsin B with IC₅₀ values of 2.12 and 3.71 µg/ml, respectively.