Periodicity of growth rings in Juniperus procera from Ethiopia inferred from crossdating and radiocarbon dating

African pencil cedar (Juniperus procera Hochst. ex Endlicher 1847) is a tropical, irregularly growing species that can produce annual growth rings in response to an annual cycle of wet and dry seasons. In this paper, we assess the periodicity of growth-ring formation for 13 stem discs from a site in Central-Northern Ethiopia by crossdating and radiocarbon dating. The crossdating process is described more transparently than usual to allow open discussion of the methodology employed. Although the ring-width series could be tentatively matched, radiocarbon dating revealed that the growth rings of the junipers from the studied site are neither annual nor represent a common periodicity. It was found that the trees are exceptionally sensitive and respond individually to the complex local climate. For future research, it is recommended to select more mesic sites with an unambiguously unimodal rainfall regime and to gain external evidence to support assumptions about the periodicity of growth-ring formation in Juniperus procera.     

Stem wood properties of mature Norway spruce after 3 years of continuous exposure to elevated [CO2] and temperature

The objective of the study was to investigate the interactive effects of elevated atmospheric carbon dioxide concentration, [CO₂], and temperature on the wood properties of mature field-grown Norway spruce ( Picea abies (L.) Karst.) trees. Material for the study was obtained from an experiment in Flakaliden, northern Sweden, where trees were grown for 3 years in whole-tree chambers at ambient (365 μmol mol⁻¹) or elevated [CO₂] (700 μmol mol⁻¹) and ambient or elevated air temperature (ambient +5.6 °C in winter and ambient +2.8 °C in summer). Elevated temperature affected both wood chemical composition and structure, but had no effect on stem radial growth. Elevated temperature decreased the concentrations of acetone-soluble extractives and soluble sugars, while mean and earlywood (EW) cell wall thickness and wood density were increased. Elevated [CO₂] had no effect on stem wood chemistry or radial growth. In wood structure, elevated [CO₂] decreased EW cell wall thickness and increased tracheid radial diameter in latewood (LW). Some significant interactions between elevated [CO₂] and temperature were found in the anatomical and physical properties of stem wood (e.g. microfibril angle, and LW cell wall thickness and density). Our results show that the wood material properties of mature Norway spruce were altered under exposure to elevated [CO₂] and temperature, although stem radial growth was not affected by the treatments.     

黄河三角洲大穗结缕草解剖结构的研究

目前对于草坪草的抗性研究多数集中在其生理方面的变化,而结合各抗性品种营养器官结构进行比较研究却报道较少。从采集自山东省无棣县沿海滩涂的大穗结缕草的营养器官解剖结构和微形态特征的研究中分析它的耐盐、耐寒、耐旱、耐践踏和弹性好的原因,从形态解剖的角度来认识大穗结缕草的优良特性。     

Agroforestry management affects coffee pests contingent on season and developmental stage

1 Management of vegetational diversity in agroecosystems is a potentially regulating factor of pest population dynamics and may affect developmental stages in different ways.
2 We investigated the population dynamics of red spider mites, coffee leaf miners, and coffee berry borers in three management types of coffee agroforests: increasing plant diversity from a few shade tree species (simple-shade agroforests), intermediate-shade tree species (complex-shade agroforests) to high-shade tree species (abandoned coffee agroforests) in Ecuador. Furthermore, we studied how changes in agroforestry management affect population stage structure of each coffee pest.
3 Our results show that agroforestry management affected seasonal patterns of coffee pests in that higher densities of red spider mites were observed from August to December, coffee leaf miners from December to February, and coffee berry borers from May to July. Moreover, specific developmental stages of red spider mites, coffee leaf miners, and coffee berry borers differed in their responses to agroforestry management. During all stages, red spider mite reached higher densities in simple-shade agroforests compared with complex-shade and abandoned agroforests. Meanwhile, coffee leaf miner densities decreased from simple-shade to complex-shade and abandoned agroforests, but only for larvae, not pupae. Similarly, only coffee berry borer adults (but not eggs, larvae and pupae) demonstrated a response to agroforestry management. Environmental variables characterizing each agroforestry type proved to be important drivers of pest population densities in the field.
4 We emphasize the importance of considering seasonal differences and population structure while investigating arthropod responses to different habitat types because responses change with time and developmental stages.     

Developmental and reproductive toxicity studies on artemisone

BACKGROUND: In order to justify clinical studies in women of child-bearing age with artemisone, a new artimisinin derivative, studies to assess fertility and early embryonic development in rats, developmental toxicity in rats and rabbits, and peri-post natal development in rats were performed. METHODS AND RESULTS: In the study on fertility and early embryonic development (dose levels 0-5-20-80 mg/kg bw/day), doses inducing clinical and organ toxicity were used. Only in severe toxicity conditions, a reduction of the number of estruses, a prolonged time to insemination, decreased numbers of corpora lutea, implantation sites, and viable fetuses were found. Two developmental toxicity studies were performed in rats (dose levels 0-1-2 mg/kg bw/day) and rabbits (dose levels 0-2.5-5.0-7.5 mg/kg bw/day). It was shown that rats were about 5 times more sensitive than rabbits. In rats, artemisone induced total litter loss (late resorptions) at 2 mg/kg body weight and above with an increased incidence of a common vascular variation and retarded ossification at this dose. In rabbits, maternal toxicity, abortion and a slightly increased incidence of cardiac ventricular septal defects was observed at 7.5 mg/kg body weight. In a pre- and postnatal developmental toxicity study in rats (dose levels 0-1-2-4 mg/kg bw/day), 4 mg/kg body weight artemisone induced clinical symptoms and affected postnatal survival, body weight gain in the F1 pups, and motor activity. CONCLUSIONS: In summary, artemisone was shown to be embryo- and fetotoxic and induced cardiac ventricular septal defects and retarded ossification in dosages where total litter loss and abortions were observed. However, no effect on reproductive and developmental parameters below severe toxic dosages could be observed. Birth Defects Res (Part B)86: 131-143, 2009. © 2009 Wiley-Liss, Inc.     

多花黄精和安徽黄精叶片发育的比较解剖学研究

对多花黄精(Polygonatum cyrtonema)和安徽黄精(P.anhuiense)不同发育时期的叶片进行了比较解剖学研究。结果表明:(1)在叶片发育过程中,气孔器指数都是由低到高,达到最高值后再逐渐降低并趋于稳定;(2)叶片长宽比在发育过程中都呈上升趋势,且与叶片形状之间有一定的相关性,叶片长宽比与表皮细胞长宽比之间没有明显的相关性;(3)两者叶片的上下表皮细胞的发育方式基本一致,都是由表皮细胞进行横向和径向生长的过程;(4)在叶片的分化过程中,首先分化出来的是表皮,其次是叶肉,最后是叶脉;(5)多花黄精的叶缘在发育早期叶肉中有大型薄壁细胞出现,但叶片成熟时,大型薄壁细胞消失或继续保存,而安徽黄精在整个发育过程中,叶肉中都未见大型薄壁细胞出现。该研究为黄精属互生叶类和轮生叶类植物的叶片发育研究积累了实验资料。     

Geometric morphometrics of the skull of Tinamidae (Aves, Palaeognathae)

The Tinamidae comprise exclusively Neotropical palaegnathous birds, with homogeneous body morphology and no sexual dimorphism. The goal of this work was to explore the variation in skull morphology between taxa and its possible correspondence with features such as diet or gender using geometric morphometric tools. Eleven landmarks were analyzed in 53 skulls of 4 genera that inhabit grasslands: Nothoprocta, Eudromia, Nothura and Rhynchotus. Intrageneric and intergeneric variability was analyzed. The genera studied here can be distinguished based on the geometric shape of their skull, with prenarial region length and neurocranium shape as the most outstanding features. In the genus Eudromia, males and females could be differentiated, while in the genus Nothoprocta, the species differentiated according to their trophic habits. This study allows establishing that genera and, in some cases, the gender of the Tinamidae can be differentiated based on cranial shape.     

外来害虫双钩巢粉虱在海南的发生及温度对其发育的影响

双钩巢粉虱Paraleyrodes pseudonaranjae Martin是近年来在我国南方新发现的一种外来害虫。本文对双钩巢粉虱在海南的发生情况进行了调查,并对各虫态形态特征及温度对其生长发育的影响进行了观察。结果表明,双钩巢粉虱在海南省的各个县(市)都有发现,其在海南省的寄主植物共有20科29属37种,主要为害椰子、槟榔、番石榴、柑桔及番荔枝。双钩巢粉虱的发育经卵、若虫(分4个龄期)发育到成虫。在18～27℃条件下,双钩巢粉虱世代发育随温度的上升而加快,在27℃时最短,为16.38 d,18℃最长,需37.41 d,在30℃发育减缓,各虫态发育速率与温度呈抛物线关系。双钩巢粉虱世代的发育起点温度和有效积温分别为9.56℃和307.75日.度,在海南一年可发生16～17代。     

感染球孢白僵菌后红火蚁体内蛋白质含量的变化

为了解球孢白僵菌Beauveria bassiana成功感染红火蚁Solenopsis invicta的生理生化机制, 本研究在室内条件下测定了经球孢白僵菌感染后红火蚁工蚁、蛹和幼蚁体内蛋白质含量的变化。结果表明: 红火蚁各虫态感染球孢白僵菌后体内蛋白质含量变化存在差异。在接种后12-72 h, 工蚁体内蛋白质含量在24 h时最高, 为47.12 mg/g, 显著低于对照的56.40 mg/g(P＜0.05), 此后呈下降趋势, 72 h时蛋白质含量下降至25.16 mg/g。幼蚁在接种36 h时体内蛋白质含量最高, 为24.13 mg/g, 此后呈下降趋势, 72 h时蛋白质含量为8.95 mg/g, 显著低于对照的24.80 mg/g。蛹感染球孢白僵菌后体内蛋白质含量一直呈下降趋势, 从12 h的36.57 mg/g降到72 h的10.42 mg/g, 与对照的38.61 mg/g相比差异显著(P＜0.05)。结果显示球孢白僵菌感染能显著降低红火蚁各虫态体内蛋白质含量。