A faunistic approach to assess potential side-effects of genetically modified Bt-Corn on non-target arthropods under field conditions

A faunistic study investigating the potential side-effects of corn (Zea mays) genetically modified to express a truncated Cry1Ab protein derived from Bacillus thuringiensis subsp. kurstaki, on non-target arthropods was carried out under field conditions. The communities of non-target arthropods in the soil, on the leaves and flying in the crop area were monitored throughout the growing season. Water-treated, untransformed corn served as a control, and a spray application of a bacterial Bt insecticide (Delfin WG) and a synthetic insecticide (Karate Xpress) used to control the European corn borer (Ostrinia nubilalis; Lepidoptera: Pyralidae) acted as positive reference treatments. Results were analyzed using a principal response curve. Significantly lower infestations by the lepidopteran target species O. nubilalis were observed in the Bt-corn plots compared to the control. No effects of Bt-corn on the communities of soil dwelling and non-target plant dwelling arthropods were observed. A trend towards a community effect on flying arthropods was observed with lower abundance of adult Lepidoptera, flies in the families Lonchopteridae, Mycetophilidae and Syrphidae, and the hymenopteran parasitoids Ceraphronidae. Effects were weak and restricted to two sampling dates corresponding to anthesis. A short but statistically significant effect of Karate Xpress and Delfin was observed on the community of plant dwellers and a prolonged effect of Karate Xpress on the soil dwellers.     

新乡太行山区木本彩叶植物资源

概括总结了新乡太行山区的木本彩叶植物资源总量、资源种类、观赏价值和开发潜力,描述了其中几种重要的木本彩叶植物,给新乡木本彩叶植物资源的开发利用提供参考.     

Plant cation-anion balance as affected by the ionic composition of the growing medium

Plants that remove an excess of cations over anions may cause soil acidification. The acidification potential of plants has been evaluated using solution culture techniques, but the influence of ionic composition of the medium on the plant cation-anion balance remains unclear. Our objective was to determine how electrolyte concentration and salt type affect the cation- anion balance of two test plants [barley (Hordeum vulgare L.) and kochia (Kochia scoparia L. Schrad.)]. Seedlings were grown in sand culture and irrigated with nutrient solution (Hoagland’s solution), which was adjusted to a range of electrolyte concentrations (target electrical conductivity of 7.5, 17.5 and 27.5 dS m⁻¹) using either chloride or sulphate salts. Increase in electrolyte concentration reduced yield of kochia, a salt-tolerant plant, by up to 38%. Total cation (Ca + Mg + K + Na) equivalents in kochia exceeded those of anions (Cl + S + P + NO₃) by 250 to 280 cmol_c kg⁻¹ of dry matter. Electrolyte concentration had no effect on the cation-anion balance of kochia, but excess cation values were significantly greater in the sulphate than in the chloride system. Kochia had a large content of water-soluble oxalate (194 to 226 cmol_c kg⁻¹), which was linearly related to the excess cation content. Growth of barley was severely restricted at the intermediate and high electrolyte concentrations. Cations exceeded anions by 21 to 59 cmol_c kg⁻¹ of barley dry matter. Excess cation content was greater in the sulphate than in the chloride medium, but electrolyte concentration did not have a consistent effect on the cation-anion balance. The small amounts of oxalate found in barley (0.9 to 2.6 cmol_c kg⁻¹) were insufficient to balance the cation excess.     

Morphology and wall ultrastructure of the spores of the Lower Devonian plant Oocampsa catheta Andrews et al., 1975

The enigmatic Lower Devonian plant Oocampsa catheta Andrews et al. (Can. J. Bot. 53 (1975) 1719) is considered intermediate between the trimerophytes and progymnosperms. In order to shed light on its evolutionary relationships, the morphology and ultrastructure of its sporangium and spores were analysed using light, scanning electron and transmission electron microscopy. In addition, dispersed spores (Grandispora douglastownense McGregor (Palaeontographica B 142 (1973) 1) and Grandispora ?macrotuberculata (Trudy VNIGNI 37 (1963) 18) McGregor (Palaeontographica B 142 (1973) 1), considered to possibly represent forms derived from O. catheta, were also examined. It is concluded that G. douglastownense and G. ?macrotuberculata are probably end members of the same spore complex and most likely are dispersed spores produced by O. catheta. Oocampsa catheta spores are bilayered. An inner body has an innermost part consisting of continuous, parallel-stacked, laminae and an outermost part consisting of more erratic, anastomosing, laminae. The inner body is surrounded by an homogeneous outer layer that is extended at the equator forming a pseudozona, and is folded on the proximal surface forming the trilete mark and on the distal surface forming spinose ornament. The spores are partially camerate. On the inside of the sporangium wall there is a layer probably representing the residue left following degeneration of a (probably secretory) tapetum. Spore morphology, gross structure and wall ultrastructure are compared to that of extant and fossil plant groups, and it is concluded that the spores of O. catheta are highly distinctive and do not conform closely to any plant group, although they show most in common with the spores of the progymnosperms.     

盆栽非洲菊基因枪介导法转化体系的建立

以非洲菊盆栽品种为材料,研究了BA和NAA不同浓度组合对不定芽诱导增殖的影响;基因枪介导法转化的不同轰击距离对转化率影响。结果表明：1．5mg／LBA的培养基上增殖倍数最高,高达8．96倍;9cm的目标轰击距离转化效率最高,达到10．9％。建立了非洲菊盆栽品种的再生和转基因体系,为非洲菊基因工程育种打下基础。     

一种快速鉴定转基因植物纯合体的新方法

植物转化中鉴定转基因植物的整合性是一个很重要的步骤,常规方法是对独立分离的转基因T1代植株产生的T2代进行转基因分离比率研究,以检测T1代的转基因整合状态,不仅费时费力,而且浪费了T1代资源。本介绍一种应用双重定量实时PCR技术鉴定转基因植物纯合子的新方法：以T1代植物DNA为模板,根据转基因后代的Ct表型值鉴定其转基因整合状态,Ct值接近2的为转基因纯合型,Ct值接近1的为转基因杂合型。用这种方法,可以同时对数十个T1代转基因幼苗的整合状态进行快速鉴定,准确率为100％。     

Host plant resistance against broomrapes (Orobanche spp.): defence reactions and mechanisms of resistance

Over 4000 species of angiosperms are able to directly invade and parasitise other plants, but only very few are weedy and parasitise cultivated plants. Together with the witchweeds (Striga spp.) and dodders (Cuscuta spp.), the broomrapes (Orobanche spp.) affect important crops causing complete yield loses with severe infestations. Genetic resistance to parasitisation remains as one of the most desirable components in an integrated control strategy. However, breeding for resistance is a difficult task and many aspects of the host/parasite interaction remain unknown. In the present work, we review the cytological and cytochemical studies investigating the mechanisms of resistance involved in the process leading to an incompatible host–parasite interaction. We have attempted to identify the main gaps and problems related to such studies with parasitic plants and present an in‐depth review of histochemical techniques used to assess mechanisms of resistance against these parasitic plants. Furthermore, we discuss future research directions and novel techniques and finally, how such techniques can be applied and incorporated within a breeding programme.