十字花科蔬菜对小菜蛾实验种群的影响

通过组建4种十字花科蔬菜上小菜蛾实验种群生命表发现,在菜心、芥蓝、芥菜和小白菜4种蔬菜上繁殖的小菜蛾实验种群增长趋势指数分别为41．0、69．5、38．2、52．4,影响种群增长的重要因子为幼虫的自然死亡,不同蔬菜种类对小菜蛾雌蛾的总产卵量和寿命无影响,但芥蓝繁殖的小菜蛾日平均产卵量显著高于其它几种蔬菜。在芥蓝和小白菜上繁殖的小菜蛾幼虫具有较高的存活概率,是其种群具有较大增长潜力的重要原因。试验结果表明,在4种蔬菜中,芥蓝提供的营养最适宜于小菜蛾种群生长、发育和繁殖,是最佳的寄主,其次为小白菜、菜心,而芥菜尽管被报道为小菜蛾成虫最喜欢产卵的寄主,由于所繁殖的小菜蛾种群在幼虫期有较高的死亡率,是最不适宜于小菜蛾生长发育的寄主。     

亚麻荠对小菜蛾幼虫取食和成虫行为反应的影响

亚麻荠是一种很少有害虫危害的油料作物。用室内生测和Y 型嗅觉仪研究了亚麻荠对小菜蛾Plutella xylostella幼虫取食和成虫行 为反应的影响。以甘蓝作对照,用亚麻荠叶片喂养的小菜蛾初孵幼虫3天后校正死亡率为79 .2%,显示了较强的致死作用;喂养小菜蛾3龄幼虫至化蛹,其存活率、化蛹率、蛹重及成 虫寿命都显著降低,表明亚麻荠对小菜蛾幼虫的生长发育有不利影响。在幼虫的取食选择实 验中,有甘蓝叶供选择时,小菜蛾幼虫不取食亚麻荠;在无可选择的情况下,小菜蛾幼虫也 取 食亚麻荠叶片,但取食量很小,与取食甘蓝叶的量相比,差异极显著。行为反应测试表明, 小菜蛾成虫对甘蓝和亚麻荠植株的挥发物都有明显的趋性反应,与对照（净化空气）相比, 差异极显著,而在甘蓝和亚麻荠之间无选择性。说明小菜蛾成虫对亚麻荠植株的挥发物具有 较强的定向反应。     

四种材料作为异色瓢虫产卵载体的适合性比较

比较了蚕豆苗叶片、甘蓝叶片、小油菜叶片和纸条作为人工扩繁异色瓢虫Harmoniaaxyridis(Pallas)时产卵载体的适合性。异色瓢虫对这 4种产卵载体有明显的选择性 ,多在蚕豆苗叶片和甘蓝叶片上产卵 ,纸条上次之 ,在小油菜叶片上产卵很少。在产卵载体对单雌产卵量影响方面 ,蚕豆苗叶片、甘蓝叶片和纸条 3者之间的差异不显著 ,且产于这 3种载体上的卵块在 ( 1 0± 1 )℃下冷藏的孵化率没有明显差异。由于纸条不会出现枯萎现象 ,易制成卵卡 ,所以可用作卵商品化时的产卵载体 ,而蚕豆苗叶片和甘蓝叶片可作为保留虫源或繁殖时的产卵载体。     

甜菜夜蛾对不同寄主植物的产卵和取食选择

为了探讨甜菜夜蛾Spodoptera exigua对不同寄主植物的产卵选择及成虫产卵选择与幼虫取食选择间的关联度, 本研究选取玉米、豇豆、甘蓝、黄瓜、棉花、辣椒和番茄7种植物进行了选择性和非选择性实验研究, 并采用Y型嗅觉仪测定了成虫对其中3种寄主植物及其挥发物抽提物的趋性。结果表明：在田间非选择性实验中, 甜菜夜蛾在不同寄主植物上的落卵量依次为：玉米>辣椒>棉花>黄瓜、豇豆、番茄>甘蓝。Y型嗅觉仪的行为测定表明, 雌成虫对玉米及其挥发物抽提物的趋性最强, 黄瓜次之, 对甘蓝的趋性最弱, 这与雌虫的产卵选择性一致。不同龄期甜菜夜蛾幼虫对寄主植物的取食选择性有所不同, 且随观测时间的延长有所改变;低龄幼虫对豇豆、玉米和黄瓜的选择性较强, 对甘蓝、番茄、辣椒和棉花的取食选择性则较弱, 高龄幼虫对辣椒也具有较强的选择性;5龄幼虫对寄主植物的选择性不如低龄幼虫明显。结果显示, 甜菜夜蛾对不同寄主植物的产卵选择性显著不同, 植物抽提物在雌成虫的产卵选择中具有重要作用, 甜菜夜蛾对寄主植物的产卵选择性和幼虫取食选择性并不一致。     

番茄抽提物对小菜蛾的忌避,拒食及抑制产卵作用

在自然变温条件下,研究了番茄抽提物对小菜蛾成虫的忌避、幼虫的拒食作用及成虫繁殖力的影响。试验表明：番茄抽提物对小菜蛾成虫具有很强的忌避作用;用番茄抽提物处理过的包菜叶饲喂小菜蛾幼虫,其拒食率达５３％;番茄提物对小菜蛾成虫产卵也有明显抑制作用,产卵量下降６０％;番茄与包菜间种能明显地抑制小菜蛾种群数量的增长。其种群可下降５０％以上。     

颗粒体病毒对不同蔬菜上小菜蛾实验种群的控制作用

通过组建施用颗粒体病毒Plutella xylostellagranulosis virus(PxGV)后4种十字花科蔬菜上的小菜蛾Plutella xylostellaL.实验种群生命表发现:小菜蛾颗粒体病毒除了能引起幼虫感病死亡外,还能显著地降低成虫的产卵量,推迟产卵高蜂1~2 d,但对化蛹及雌蛾寿命无显著影响。在种群水平上,病毒对小菜蛾的控制作用综合表现为压低了小菜蛾种群增长趋势指数,在菜心、芥蓝、芥菜和小白菜上小菜蛾实验种群增长趋势指数在分别为13.7,12.3,10.7和22.7,病毒对小菜蛾种群的干扰作用控制指数(IIPC)分别为0.334,0.177,0.280和0.433,表明病毒对小菜蛾种群的控制能力受到寄主植物的影响,在芥蓝上控制能力最强,其次为芥菜和菜心,而小白菜最次。     

四种十字花科蔬菜上小菜蛾自然种群连续世代生命表

利用作用因子生命表技术,组建芥菜、芥蓝、小白菜和菜心4种十字花科蔬菜上小菜蛾自然种群连续世代生命表,分析寄主植物和生物因子对小菜蛾种群数量的控制作用。结果表明：在4种十字花科蔬菜的一造菜上,小菜蛾均能完成两个世代。虽然小菜蛾在芥菜上的初始卵量最高,但害虫种群总增长倍数在芥蓝上最高,其次为小白菜,菜心和芥菜,分别为17．64、11．90、11．43和3．76。这说明尽管芥菜对小菜蛾成虫的产卵有一定的吸引作用,但不适合小菜蛾生长发育。芥蓝是最适宜小菜蛾种群增长的寄主。生物因子在小菜蛾自然种群控制中起着重要的作用,但是在不同种类十字花科蔬菜上,天敌类群对小菜蛾控制作用存在一定差异。除芥菜之外,寄生性天敌对芥蓝、菜心和小白菜上的小菜蛾种群控制作用最大,其次为“捕食及其它”,病原微生物的控制作用最小。“捕食及其它”对芥菜上小菜蛾种群的作用非常明显,如果排除此因子作用,小菜蛾种群两代后将增长126．03倍。该因子是导致芥菜小菜蛾自然种群增长趋势指数低的主要原因。因此在制定小菜蛾防治策略时,应考虑蔬菜的种类和布局,加大对芥蓝小菜蛾种群的防治力度;芥菜可作为一种诱杀植物种植,以吸引小菜蛾产卵,并集中防治。这些防治策略在小菜蛾综合治理中具有重要的实际意义。     

温室白粉虱对几种园艺植物的偏好性

温室白粉虱Trialeurodesvaporariorum是世界性害虫,每年都造成巨大的经济损失。研究了温室白粉虱在多种园艺植物混栽温室内对不同植物的选择性,结果表明在2 0种常见蔬菜和花卉中,可危害其中1 3种;温室白粉虱对其中6种寄主植物(旱金莲、一品红、菊花、番茄、小白菜和羽叶甘蓝)的选择性有显著差异,其种群数量为旱金莲和番茄显著多于小白菜、一品红和菊花,羽叶甘蓝显著少于其它5种植物;不同的虫态之间排序有小变动;温室白粉虱在番茄植株上部的垂直分布表现为卵和成虫在第3叶居多,若虫在第5叶居多,伪蛹在第9叶居多。     

小菜蛾对多胺的嗅觉反应

在实验室条件下利用Y型嗅觉仪测试了小菜蛾Plutella xylostella成虫对多胺的嗅觉反应。结果表明：与蒸馏水对照比较,小菜蛾在交配前和交配后对精胺、亚精胺和腐胺这3种被测的多胺均有明显的趋性反应,但对3种多胺两两之间的选择则无显著差异;在对3种多胺和甘蓝Brassica oleracea叶汁之间的选择中,除未交配雄蛾对腐胺有明显的趋性（与甘蓝叶汁比较）和交配后雌蛾对甘蓝叶汁有明显的趋性（与精胺比较）外,其他均没有显著差异。表明多胺对小菜蛾具有引诱作用。     

杀虫剂对小菜蛾实验种群的影响

用生物农药8010(100亿活芽孢／克)500、1000、2000、4000倍液和21%灭杀毙乳油(6％氰戊菊酯 15％马拉硫磷)1000、2000、4000倍液在27℃恒温条件下对小菜蛾进行卵期处理。各处理对小菜蛾的卵孵化率无影响,但对其幼虫的死亡率则影响较大。不同处理间小菜蛾的发育速率和成虫产卵量存在着较大的差异;各项种群参数,即每雌平均产雌量(E)、净增殖率(R0)、世代平均历期(T)、内禀增长能力(rm)、周限增长率λ)、双倍时间(Dr)等也存在差异。     

Resistance of some cultivated Brassicaceae to infestations by Plutella xylostella (Lepidoptera: Plutellidae)

Selecting insect-resistant plant varieties is a key component of integrated management programs of oligophagous pests such as diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), but rigorous research on important life history parameters of P. xylostella in relation to host plant resistance is rare. We evaluated six conventional brassicaceous species, namely, Brassica napus L. 'Q2', B. rapa L., B. juncea (L.) Czern., B. carinata L., B. oleracea L., and Sinapis alba L., and two herbicide-tolerant cultivars, namely, B. napus 'Liberty' and B. napus 'Conquest' for their resistance against P. xylostella. Brassicaceae species and cultivars varied considerably in their susceptibilities as hosts for P. xylostella. Sinapis alba and B. rapa plants were highly preferred by ovipositing females and trichome density on adaxial and abaxial leaf surfaces had nonsignificant effects on P. xylostella oviposition. Larval survival was similar on the genotypes we tested, but host plants significantly affected larval and pupal developmental time, herbivory, pupal weight, silk weight, adult body weight, forewing area and longevity (without food) of both male and female P. xylostella. Larval and pupal development of females was fastest on B. juncea and S. alba, respectively. Specimens reared on B. napus Liberty and B. oleracea, respectively, produced the lightest female and male pupae. Defoliation by both female and male larvae was highest on B. rapa, whereas least herbivory occurred on S. alba. Females reared on S. alba were heavier and lived longer in the absence of food than their counterparts raised on other tested host plants. Brassica oleracea could not compensate for larval feeding to the level of the other species we evaluated. B. napus Conquest, B. napus Q2, B. carinata, B. rapa, and S. alba produced, respectively, 1.6-, 1.8-, 1.8-, 3.9-, and 5.5-fold heavier root systems when infested than their uninfested counterparts, suggesting that these species were better able to tolerate P. xylostella infestations.     

Laboratory evaluations of a wild crucifer Barbarea vulgaris as a management tool for the diamondback moth Plutella xylostella (Lepidoptera: Plutellidae)

The term 'dead-end trap cropping' has recently been proposed to identify a plant that is highly attractive for oviposition by an insect pest, but on which offspring of the pest cannot survive. The potential of the wild crucifer Barbarea vulgaris R. Br. to allure and serve as a dead-end trap crop for the diamondback moth Plutella xylostella (L.), an important pest of cruciferous crops worldwide, was examined in laboratory experiments. When P. xylostella adults were provided with a dual-choice of plants of B. vulgaris, and Chinese cabbage Brassica campestris (L.), in one arena, adult moths laid 2.5-6.8 times more eggs on the former than on the latter. When P. xylostella adults were provided with a dual-choice of plants of B. vulgaris and common cabbage Brassica oleracea L., adult moths laid virtually all their eggs on the former and ignored the latter. Nearly all P. xylostella eggs laid on the three species of plants hatched successfully, but nearly all individuals on plants of B. vulgaris died as neonates or early instar larvae, while 87-100% of the larvae on Chinese cabbage and common cabbage survived to pupation. Dual choice tests with a Y-tube olfactometer showed that volatiles from B. vulgaris were much more attractive to P. xylostella adults than those from common cabbage. The results demonstrate that B. vulgaris has a great potential as a dead-end trap crop for improving management of P. xylostella. Factors that may influence the feasibility of using B. vulgaris as a trap crop in the field are discussed, and ways to utilize this plant are proposed.     

Oviposition by Plutella xylostella (Lepidoptera: Plutellidae) and effects of phylloplane waxiness

Three approaches were used to investigate effects of host plant epicuticular waxes on oviposition site selection by Plutella xylostella (L.). In the first approach, oviposition on canola (Brassica napus L.) that had epicuticular wax reduced by application of a carbamate herbicide (S-ethyl dipropylthiocarbamate) was compared with oviposition on untreated control plants. A second approach compared oviposition on sibling strains of B. napus with different wax blooms (glossy and waxy), and a third approach compared oviposition by P. xylostella on parafilm that had been applied to glossy and waxy B. napus strains for transfer of leaf components. Significantly more eggs were deposited on herbicide-treated plants (with reduced epicuticular wax) than on untreated controls. Similarly, more eggs were deposited on glossy than on waxy sibling strains of B. napus. In parafilm assays significantly more eggs were deposited on treated than on untreated parafilm. Several mechanisms could explain the differences in attractiveness of surfaces with varying wax content as oviposition sites for P. xylostella, including visual, chemical, and tactile differences between substrates. These mechanisms are discussed.     

小菜蛾幼虫对不同寄主的取食嗜好性及其适宜性

对不同寄主种类、不同寄主形态和不同寄主饲喂的小菜蛾(Plutella xylostella)幼虫之间的取食嗜好性比较试验表明,小菜蛾幼虫优先取食大白菜、萝卜或菜心幼苗,其次为油菜和甘蓝幼苗,在大白菜与油菜幼苗之间的取食选择比例是93.33%和6.67％;在甘蓝与菜心幼苗之间的取食选择比例是16.67%和83.33%.小菜蛾幼虫的取食嗜好性受饲喂寄主种类的影响,偏食大白菜或菜心幼苗.小菜蛾幼虫选择寄主取食的次序与寄主体内可溶性糖或淀粉含量没有明显关系,但与两者的相对量呈一定的负相关.取食大白菜或菜心幼苗的小菜蛾生长良好,单头取食达0.583～0.637 cm², 单头体重达2.07～2.18 mg, 与取食甘蓝或油菜幼苗的幼虫在取食量、个体发育方面有明显差异.小菜蛾幼虫也喜好取食已经被虫危害过的幼苗.     

人工合成甘蓝型油菜特长角变异系的选育

用中国西藏东部采集的1个白菜型油菜地方品种与云南甘蓝类蔬菜白花芥蓝远缘杂交,人工合成了甘蓝型油菜新材料,从杂种后代中通过系统选育,获得了1个特长角变异系,其主花序中部角果平均长度20cm左右,果身长16～18cm,果喙长3cm左右.从中获得的极端最长角果达31.5cm,果身长26.1cm,果喙长5.4cm.这是迄今芸苔属植物中很少见到的长角果油菜材料.该材料的平均角果长度大约为普通甘蓝型油菜的3倍左右,遗传已基本稳定,定名为川农特长角.本文报导其选育经过和主要特征特性,并对其育种和研究利用价值作了简要分析.     

Manipulating the attractiveness and suitability of hosts for diamondback moth (Lepidoptera: Plutellidae)

Ovipositional preference and larval survival of the diamondback moth, Plutella xylostella (L.), were compared among cabbage, Brassica oleracea L. variety capitata; glossy collards, Brassica oleracea L. variety acephala; and yellow rocket, Barbarea vulgaris (R. Br.) variety arcuata in different treatments of planting density, host plant age, intercropping, and water stress in 2003 and 2004. P. xylostella laid nearly twice as many eggs per plant in the high planting densities of glossy collards and yellow rocket than in the standard planting densities. Ovipositional preference was positively correlated with plant age in cabbage, glossy collards, and yellow rocket. Larval survival on cabbage was 1.9 times higher on 6-wk than on 12-wk-old plants, whereas larval survival on collards was 12.1 times higher on the younger plants. No larvae survived on either 6- or 12-wk-old yellow rocket plants. Intercropping cabbage with either tomato, Lycopersicon esculentum Mill., or fava bean, Vicia fava L., did not reduce the number of eggs laid on cabbage. No significant differences in oviposition were found between water-stressed and well-irrigated host plants treatments. Yet, P. xylostella larval survival on water-stressed cabbage was 2.1 times lower than on well-irrigated cabbage plants. Based on our findings, the effectiveness of trap crops of glossy collards and yellow rocket could be enhanced by integrating the use of higher planting densities in the trap crop than in the main crop and seeding of the trap crop earlier than the main crop.     

芸薹属多倍体植物基因组进化的RAPD分析

多倍化是促进高等植物发生进化的重要力量。为了更清楚地了解多倍体在形成之后其基因组是如何进化的,利用38个随机引物对芸薹属Brassica L.禹氏三角（U’Triangle）中的多倍体物种及其祖先二倍体物种进行了研究。根据扩增出的273条带计算了遗传距离,并用UPGMA法进行了聚类分析。结果发现,二倍体物种B.campestris（AA）与B.oleracea（CC）的亲缘关系比与B.nigra（BB）的要近;异源多倍体B.napus（AACC）比起其二倍体祖先之一B.campestris（AA）与另一个     

Immunopurification and Immunocharacterization of the Glucosinolate Biosynthetic Enzyme Thiohydroximate S-Glucosyltransferase

Preparing homogeneous UDP-glucose:thiohydroximate S-glucosyltransferase (S-GT), the penultimate biosynthetic enzyme of glucosinolates, by standard chromatographic methods has yielded too little protein for adequate purity evaluation, identity verification, and structural analysis. The low yields were apparently due to low abundance in source tissues, aggravated by enzyme instability. Here we describe an immunological method for purification of workable quantities from florets of Brassica oleracea ssp. botrytis (cauliflower). Florets that had undergone browning due to exposure to sunlight contained higher S-GT activities than are normally found in Brassica tissues. S-GT was adsorbed from crude tissue extracts onto an agarose-monoclonal antibody complex. Elution from the complex required harsh alkaline conditions (pH 11.5), giving extremely variable activity recoveries (maximum 20%). The eluate contained two proteins that could be separated readily by preparative polyacrylamide gel electrophoresis or anion-exchange chromatography. The overall S-GT protein recovery was estimated at less than 200 [mu]g/kg of cauliflower tissue. Molecular weight determinations with homogeneous cauliflower S-GT gave relative molecular weight (Mr) values of 55,500 as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 57,600 by gel chromatography; isoenzymes with isoelectric point values of 4.80 and 4.95 were identified. A polyclonal antibody raised against denatured enzyme showed broad cross-reactivity in immunoblots with S-GT from a number of Brassica species and other crucifers. The monoclonal antibody that was used in the immunopurification was much more specific; it exclusively precipitated S-GT isoenzymes that had their genomic origin in the primary diploids B. oleracea and Brassica campestris. Thus, all of the S-GT was precipitated from the amphidiploid Brassica napus, which is a hybrid of B. orleracea and B. campestris. About half of the S-GT was precipitated from the amphidiploids Brassica carinata and Brassica juncea, which have B. oleracea and B. campestris as one of their parents, respectively. It was shown that the S-GT isoenzymes of B. juncea with Mr 55,500 and about 57,000 originate from the parents B. campestris and B. nigra, respectively.     

Evaluating trap crops for diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)

Potential trap crops for the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), were evaluated through a series of ovipositional preference and larval survival experiments in outdoor screenhouses in 2002 and 2003. Hosts examined as trap crops were glossy and waxy collards, Brassica oleracea L. variety acephala; Indian mustard, Brassica juncea (L.) Czern; and yellow rocket, Barbarea vulgaris (R. Br.) variety arcuata. More eggs were laid on the potential trap crops, with the exception of waxy collards, than on cabbage. When P. xylostella was offered multiple hosts at the same time, numbers of eggs laid on glossy collards, Indian mustard, and yellow rocket were 3, 18, and 12 times greater than on cabbage, respectively. Similarly, when P. xylostella was offered a single trap crop host and cabbage, numbers of eggs laid on glossy collards, Indian mustard, and yellow rocket were 300, 19, and 110 times greater than on cabbage, respectively. Our studies suggest differences in oviposition between the potential trap crops and cabbage were likely due to host volatiles, leaf morphology and color, or a combination of these factors, rather than to total leaf areas, leaf shape, or plant architecture. Two-choice tests with a Y-tube olfactometer indicated that plant volatiles were major factors in P. xylostella host preference. The percentage larval survival from egg to pupation was 22.2% on cabbage, 18.9% on waxy collards, and 24.4% on Indian mustard, whereas survival was significantly lower on glossy collards (6.7%) and yellow rocket (0%). Based on our tests, it seems that yellow rocket may be the best candidate for use as a trap crop for P. xylostella because it is highly attractive for oviposition, but larvae do not survive on it.     

传粉导致的转基因白菜与其近缘种属材料间的基因流动

从形态、染色体及分子水平上证实,转基因不结球白菜(Brassica campestris ssp．chinensis var．utilis Tsen et Lee)中编码除草剂Basta抗性的bar基因能在田间条件下,经自然传粉,以较高频率侵入芜菁(B．campestris ssp．rapifera)、结球白菜(B．campestris／sssp．pek／nens／s)和不结球白菜(B．campestrs ssp．ch／nens／s)的基因组中,也能少量侵入同属异种的甘蓝型油菜(B.napus)基因组中;在温室人工辅助授粉条件下,除在上述种中的基因漂移率提高外,bar基因尚能以一定频率侵入同属的黑芥(B．nigra)、埃塞俄比亚芥(B．car／nata)、芥菜(B．juncea)基因组中,但始终未能得到转基因白菜与结球甘蓝(B．oleracea)、萝卜(尺．sativus)的杂种。转基因白菜与十字花科的7种常见杂草经温室人工辅助授粉,也均未得到抗性杂种。