Enigmatic morphology of Djinga felicis (Podostemaceae – Podostemoideae), a badly known endemic from northwestern Cameroon

Djinga is a monotypic genus restricted to the Cameroon Ridge (‘Dorsale Camerounaise’) of NW Cameroon. Besides the type locality Mount Djinga (Adamawa Province, near Tignère), it also grows in waterfalls near Mount Oku (NW Province). This paper describes the structure and development of Djinga felicis using scanning electron microscopy and microtome sections. Cusset's protologue is enriched considerably. Roots are green, dorsiventrally flattened and adherent to submerged rocks. They are broad ribbons or crusts (up to 1 cm broad) which branch exogenously. Root‐borne shoots (up to 17 cm) have filamentous leaves with sheaths and (occasionally) attached stipules. Flowers are borne as part of reproductive short shoots which arise exogenously along the stems and endogenously along the roots. Djinga shows non‐axillary stem branching. Reproductive shoots along the main stem usually stay short. They arise from the abaxial side of double‐sheathed leaves, a key innovation of Podostemoideae. These short shoots shift into pocket‐like stem positions clearly below their associated leaves. Each flower bud inside a spathella is erect, but with an inclined ovary. The flowers are unistaminate with a broad connective. Unlike many other Podostemoideae, the tricolpate pollen grains are arranged in both dyads and monads. The ovary is globular and unilocular. The mature 8‐ribbed capsule dehisces by two slightly unequal valves, releasing 40–50 seeds. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 64–81.     

中国内蒙古道虎沟中侏罗世蚊蝎蛉科(昆虫纲,长翅目)昆虫化石

描述蚊蝎蛉科1新属和3新种:新属Decoribittacus gen.nov.,新种美脉华美蚊蝎蛉Decoribittacus euneurus sp.nov.,斑点华美蚊蝎蛉Decoribittacus stictus sp.nov.和长翼卡拉蚊蝎蛉Karattacus longia latus sp.nov..同时修订了卡拉蚊蝎蛉属Karattaus的属征.所有的化石标本都来自内蒙古宁城县道虎沟中侏罗世九龙山组地层,模式标本现在保存于首都师范大学生命科学学院.     

中国发现全沟姬蜂属(膜翅目,姬蜂科)及二新种记述

报道在江西省发现的我国姬蜂科1新纪录属:全沟姬蜂属 Amrapalia Gupta et Jonathan,1970,并记述2新种:黄面全沟姬蜂 A.flavifacialis sp.nov.、黑面全沟姬蜂 A.nigrifacialis sp.nov..指出了与近似种的鉴别特征.编制了我国已知种检索表.     

A new genus and species of lungless salamander (family Plethodontidae) from the Appalachian highlands of the south-eastern United States

We describe a striking new species of the lungless salamander family Plethodontidae from the Appalachian foothills of northern Georgia, USA. This miniature species, c . 25–26 mm (adult standard length), is so distinctive genetically and morphologically that we erect a new genus, the first new genus of amphibian described from the US in nearly 50 years. It is unique among plethodontids from eastern North America in displaying sexual colour dimorphism. Although certain miniaturized plethodontids exhibit a reduced number (four) of digits on the pes, this species possesses a full complement of five toes. A plethodontid phylogeny derived from mitochondrial and nuclear DNA sequences places it in the tribe Spelerpini as the sister taxon to Eurycea . Genetic divergence between the new species and Eurycea for the nuclear gene Rag -1 (4.7%) is among the higher levels observed between long-established spelerpine genera (2.6–5.3%). This new form appears to be rare and is of immediate conservation concern.     

AgNO3对网纹甜瓜试管苗再生和玻璃苗产生的影响

以网纹甜瓜品种‘中蜜1号’为试材,在其不同培养阶段添加不同浓度AgNO3,检测不定芽的诱导率和增殖率、玻璃苗发生率和生根情况的结果表明,添加AgNO3后,子叶的愈伤组织诱导率下降,添加70μmol·L^-1AgNO3可促进不定芽的诱导,50～60μmol·L^-1AgNO3明显促进不定芽增殖,并完全抑制玻璃苗的产生,添加50μmol·L^-1AgNO3的生根最好。     

Host Selection by the Herbivorous Mite Polyphagotarsonemus latus (Acari: Tarsonemidae)

This study examined the host-selection ability of the broad mite Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae). To make long-distance-shifts from one host plant patch to another, broad mites largely depend on phoretic association with whiteflies. However, the host plants of whiteflies and broad mites are not necessarily the same. We determined the host-preference and acceptance of free-moving and phoretic broad mites using two behavioral bioassays. We used a choice test to monitor host selection by free-moving mites. In the case of phoretic mites, we compared their rate of detachment from the phoretic vector Bemisia tabaci placed on leaves taken from various host plants. The suitability of the plant was further determined by monitoring mite’s fecundity and its offspring development. We compared the mites’ responses to young and old cucumber (Cucumis sativus cv. ‘Kfir’) leaves (3rd and 8–9th leaf from the apex, respectively), and two tomato (Solanum lycopersicum cvs. ‘M82’ and ‘Moneymaker’). Free-moving mites of all stages and both sexes preferred young cucumber leaves to old cucumber leaves and preferred young cucumber rather than young tomato leaves, demonstrating for the first time that broad mites are able to choose their host actively. As for phoretic mated females, although eventually most of the mites abandoned the phoretic vector, the rate of detachment from the whitefly vector was host dependent and correlated with the mites’ fitness on the particular host. In general, host preference of phoretic female mites resembled that of the free-moving female. Cues used by mites for host selection remain to be explored.     

外源亚精胺对盐胁迫下黄瓜(Cucumis sativus L.)叶绿体活性氧清除系统和结合态多胺含量的影响

采用营养液水培,研究了外源亚精胺(Spd)对NaCl胁迫下抗盐能力不同的两个黄瓜品种幼苗生长、叶绿体中活性氧清除系统、转谷酰胺酶(TGase)活性、结合态多胺含量及植株光合速率的影响.结果表明,外源Spd能提高NaCl胁迫下叶绿体中TGase活性、叶绿体结合态腐胺(Put)、Spd、精胺(Spm)及总多胺含量;提高超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)活性,提高抗坏血酸(AsA)、类胡萝卜素(Car)、还原型谷胱甘肽(GSH)含量及还原型谷胱甘肽/氧化型谷胱甘肽(GSH/ GSSG)比值,降低脱氢抗坏血酸/抗坏血酸(DAsA/AsA)比值;同时显著降低叶绿体过氧化氢(H2O2)和丙二醛(MDA)含量,提高植株净光合速率,缓解NaCl胁迫对幼苗生长的抑制.表明Spd对黄瓜盐害的缓解作用之一可能是通过提高叶绿体结合态多胺含量和叶绿体活性氧清除能力,从而缓解盐胁迫对叶绿体膜的伤害.     

Photothermal model of plant development

The development of plants depends on the photoperiod length, light intensity, temperature, and length of light day integral. The reaction of a plant to the day length or daily light integral can depend on both the range of studied light intensities and photoperiod. Based on the data concerning the effects of light and thermal integrals on the developmental rate of plants of different photoperiodic groups, a photothermal model of plant development was proposed. The model was used to calculate the lengths of optimal photoperiods and ranges of daily temperature gradients ensuring the highest developmental rate of some plants, such as soybean, wheat, cucumber, and barley.     

羊驼线粒体12srRNA/tRNA-Val/16rRNA 基因序列测定及分子进化研究

对GaneBank中登录的部分骆驼科动物线粒体12 srRNA/tRNA-Val/16 rRNA基因序列进行同源性比较,并借助DNAstar软件设计引物,扩增并进行序列分析,旨在揭示其遗传变异的规律。PCR条件优化后成功扩增出长度为1 014 bp的DNA片段,b lastn分析显示,该片断与骆驼科动物的同源性高于95%,所获得片断包括30bp的12 srRNA基因部分序列,71 bp的tRNA-Val基因全序列和913 bp的16 srRNA基因部分序列。利用RNA-structure 4.2 RNA分析软件绘制了部分骆驼科动物的线粒体tRNA-Val推导性二级结构图,比较结果显示,羊驼线粒体tRNA-Val氨基酸臂和反密码子环呈属间特异性遗传。     

中国单种属大型担子菌及其地理分布(英文)

中国大型担子菌单种属113个,隶属于48科,10目,其中一部分是世界单种属,另一部分为中国境内目前只报道一个种的属。单种属的分类学地位独特,区系分布上也表现出一定的特点。因此,单种属的亲缘关系和菌物地理学研究具有重要的理论意义。