Phenolic content of daylight-exposed and shaded floating leaves of water lilies (Nymphaeaceae) in relation to infection by fungi

Under suboptimal growing conditions (e.g. a lack of sunshine), floating leaves of Nymphaea alba and Nuphar lutea can become heavily infected with the fungi Colletotrichum nymphaeae and Pythium F, respectively. These fungi normally act as decomposers of senescent leaves. Mature leaves of Nymphaea alba and Nuphar lutea contain high concentrations of phenolics, secondary substances known for their fungistatic properties. The production of these compounds requires energy and primary metabolites. The hypothesis that suboptimal growing conditions reduce the ability of nymphaeids to maintain a sufficiently high level of phenolics, thereby making them more vulnerable to infection by fungi, was tested. Outdoor mesocosm experiments were used to examine the response of floating leaves of Nymphaea alba and Nuphar lutea to reduced light availability. Shading significantly reduced the phenolic content of the leaves. This was accompanied by higher disease severity. The outcome of this experiment is also discussed in relation to the higher nitrogen content measured in shaded leaves. Received: 8 February 1997 / Accepted: 12 July 1997     

中国四种小型鸟类代谢产热的气候适应

采用封闭式流体压力呼吸计 ,分别在 5 - 35°C、 10 - 30°C和 10 - 35°C的环境温度范围内测定了黄眉(Emberizachrysophrys)、红胁绣眼鸟 (Zosteropserythropleura)、画眉 (Garrulaxcanorus)和红嘴相思鸟 (Leio thrixlutea)的耗氧量、热传导、体温等指标 ,探讨了其代谢产热特征。黄眉、红胁绣眼鸟、画眉和红嘴相思鸟的热中性区分别为 2 5 - 30°C、 2 5 - 2 7 5°C、 2 2 5 - 2 7 5°C和 30 - 32 5°C。在 5 - 30°C的温度范围内 ,黄眉和画眉能保持稳定的体温 ,分别为 4 0 5 8± 0 2 6°C和 4 1 6 8± 0 11°C ;红胁绣眼鸟和红嘴相思鸟的体温随环境温度的降低有下降的趋势。在热中性区内 ,黄眉、红胁绣眼鸟、画眉和红嘴相思鸟的平均基础代谢率分别是3 6 5± 0 14、 4 6 9± 0 2 7、 3 5 5± 0 14和 4 2 4± 0 17mlO2 / (g·h) ,分别是体重预期值的 12 8%、 2 30 %、 6 0 %和 12 0 %。在下临界温度以下 ,黄眉、红胁绣眼鸟、画眉和红嘴相思鸟的最小热传导分别是 0 2 4、 0 31、 0 2 1和 0 34mlO2 / (g·h·°C) ,分别是体重预期值的 14 9%、 14 9%、 2 15 %和 2 4 3%。这些小型鸟类的生理生态学特征是 :(1)黄眉和红胁绣眼鸟有高的基础代谢率和相对低的下临界温度 ,适应低温环境     

Scope for genetic enhancement of the parasitisation potential of four native strains of Trichogrammatoidea sp. nr. lutea Girault (Hymenoptera: Trichogrammatidae) in Kenya

In response to emerging interest in commercial mass production of Trichogramma for Helicoverpa armigera biocontrol in eastern Africa, laboratory experiments were undertaken to assess the scope for genetic enhancement of the parasitisation potential of native strains of the local common trichogrammatid species, Trichogrammatoidea sp. nr. lutea. Four promising strains (ex-Kilifi – Kilifi District, ex-Kwa Chai – Kibwezi District, ex-Rarieda – Bondo District and ex-Ebuhayi, Kakamega District) were tested for cross-mating in reciprocal combinations with focus on fecundity and progeny female ratio. While all the crosses resulted in F1 progeny of both sexes, significant differences were observed between homogamic and reciprocal heterogamic crosses in fecundity, progeny production, proportion of female progeny and adult longevity. Among all the crosses, the cross between ex-Rarieda strain females and ex-Kilifi strain males resulted in progeny that was significantly superior in fecundity and progeny female ratio. Conversely, Kilifi strain females crossed to males from ex-Rarieda strain gave rise to progeny with relatively low fecundity and female ratio. There were significant differences between homogamic crosses and most reciprocal heterogamic crosses in the major biological attributes. Genotypic and phenotypic variance-covariance matrices generated for six life-history traits showed high positive correlations for most traits in both inbred (P<0.05) and reciprocal heterogamic crosses (P<0.05 and P<0.001). Fecundity and number of female offspring were the most important factors in the heterogamic crosses. The results confirmed the scope for genetic enhancement through inter-strain crossing for improving the field impact potential of T. sp. nr. lutea being targeted for commercial mass production.     

高产谷胱甘肽新菌种的选育及其发酵条件的研究

通过对谷胱甘肽新产生菌——藤黄八叠球菌进行紫外诱变处理,筛选到一株抗乙硫氨酸和氯化锌的抗性菌株,该突变株发酵生产谷胱甘肽的产量比出发菌株提高268．9％。通过对碳源、氮源、温度、初始pH等发酵条件对该菌株生物合成谷胱甘肽的影响研究,表明突变株HY78在发酵温度37℃、初始pH7.0、摇床转速180r／min条件下,摇瓶发酵26h,该高产菌株在发酵液中合成谷胱甘肽的产量可达160．628mg／L。     

Soil diaspore reserves above the timberline in the Austrian Alps

Soil diaspore reserves are considered to support self-healing processes after vegetation disturbances. Therefore, the stratified reserves of viable diaspores in superimposed soil layers of four sites above the timberline in the Austrian Alps were assessed. At each site, a semi-natural (“undisturbed”) extensive alpine pasture and the disturbed vegetation on hiking trails were investigated. Eighty soil cores in total (corresponding to 400 slices, each representing a 1-cm layer between 0 and 5 cm depth) were taken in autumn and subjected to germination tests after vernalization. The total diaspore numbers in disturbed and undisturbed plots did not differ significantly, but all undisturbed soils contained higher species numbers than disturbed ones. Seed shape and size clearly influenced the vertical distribution. Intact soils showed a significant decrease in big/long diaspores with increasing soil depth. Disturbances influenced the aboveground species composition and therefore the distribution of seeds of different size. In case of disturbances, the restriction of most big seeds to superficial layers means a threat for small populations of rare and protected species such as Viola lutea subsp. sudetica with relatively big seeds near the soil surface. When the disturbances stop, the diaspore communities might initiate a first, but with respect of landscape protection and preservation of species diversity insufficient step of vegetation restoration.     

Progesterone exposure of the preovulatory follicle in the seasonally anestrous ewe alters the expression of angiogenic growth factors in the early corpus luteum

Gonadotrophin releasing hormone (GnRH)-induced ovulation in seasonally anestrous ewes is associated with a high incidence of defective corpora lutea (CL), which can be completely eliminated by priming ewes with progesterone before GnRH treatment, but the physiological basis of this has remained elusive. This study tested the hypothesis that progesterone priming eliminates defective luteal function by altering the expression of Vascular Endothelial Growth Factor (VEGF), its receptor VEGFR-2, and angiopoietin (ANG)-1, ANG-2 and their receptorTIE-2 in the early CL. Fifteen seasonally anestrous ewes were treated by i.m. injection with 20 mg of progesterone 3 days before the start of GnRH treatment, while another 15 animals served as controls. Intravenous injections of 500 ng GnRH were given to all the ewes every 2 h for 28 h, followed by a 300 μg GnRH bolus injection to synchronize the preovulatory luteinizing hormone (LH) surge. Corpora lutea were collected 1, 2 and 4 days after ovulation and analyzed for protein and mRNA expression of VEGF, VEGFR-2, ANG-1, ANG-2 and Tie-2 using Western Immunoblotting and in situ hybridization. VEGF, VEGFR-2 and ANG-1 expression was significantly higher (P ≤ 0.05) in the CL of progesterone-primed animals compared to non-primed ones. However, no differences were observed in the ANG-2 or Tie-2 expression levels between the two treatment groups. These data suggest that progesterone priming of the preovulatory follicle alters the expression of some angiogenic growth factors in the early CL, leading to greater vascular stability and thereby normal luteal function.     

The distribution and biology of Lonchopteridae (Diptera) in upland regions of northern England

Abstract. 1. A survey was made of the distribution of Lonchopteridae over 2 years at forty sites in northern England. Material was collected by pitfall trapping.
2. Two species, Lonchoptera lutea and L.furcata , were taken in approximately similar numbers. No other species were recorded.
3. Considerable separation of the two species was found, with both species occurring at ten sites, whilst one species only was taken at twenty-five sites. L.furcata occurred coinrnonly on upland mineral sods, shallow peat soils and on lowland bogs whilst L.lutea was numerically most abundant on upland blanket bog.
4. Almost 39% of the L.lutea specimens and 14% of the L.furcata captures were males.
5. The capture of numbers of males of L.furcata is unusual, since the species is regarded as being parthenogenetic and males occur only in a very small part of the species' range. Confirmation of the association between the males and females of L.furcata is given, whilst there is close agreement between the cliaetotaxy of British males and females, and British and continental European females. The suggestion that the males belong to an undescribed species is rejected.
6. The seasonal capture of L.lutea adults is similar at all altitudes. Captures of males of L.furcata show an abrupt seasonal change above and below about 420 m; captures being in mid-summer in the higher altitude zone and between October and December at lower altitudes. The captures of females of L.furcata show the same trend, but this is partially obscured by the longer life-span of the females. It is suggested that this difference represents a change in the lifecycle, possibly from an annual to a biannual one at the higher altitudes.
7. The biology and distribution of the Lonchopteridae at low altitudes requires investigation.