Repelling properties of some plant materials on the tick Ixodes ricinus L.

The repellent effects on nymphal stages of Ixodes ricinus L. of some plant materials have been studied in the laboratory. The plant material consisted of an ethanolic extract from Achillea millefolium L., and volatile oils of birch and/or pine tar, citronella, cloves, eucalyptus, geranium, lavender, lily of the valley and peppermint. The most pronounced effects were observed for the oils of citronella, cloves and lily of the valley. They possessed repelling activities of the same magnitude as the reference repellent DEET (N,N-diethyl-m-toluamide). Some major constituents of these oils, e.g. citronellol and geraniol (oil of citronella and lily of the valley) and eugenol (oil of cloves) showed pronounced repelling effects. This was also the case for phenethyl alcohol, a minor component in the oil from lily of the valley.     

Geranium macrorrhizum L. (Geraniaceae) essential oil: a potent agent against Bacillus subtilis

The volatile hydrodistilled compounds from aerial parts and rhizomes of the ethnopharmacologically highly valued plant species Geranium macrorrhizum L. were screened for their antimicrobial activity in disc‐diffusion and microdilution assays. The assays pointed out to a very high and selective activity of the oils against Bacillus subtilis with minimum inhibitory concentrations (MIC) of 0.4–1.0 μg/ml. This prompted us to perform detailed compositional analyses of the oils. GC and GC/MS analyses allowed the identification of 283 constituents. The oils consisted mainly of sesquiterpenoids, the main ones being germacrone (49.7% in the oil from aerial parts) and δ‐guaiene (49.2% in rhizome oil). Significant qualitative and quantitative compositional differences in the oils from the two plant parts were observed. Further antimicrobial testing enabled us to determine that germacrone, the major constituent of the oil from aerial parts, was not the sole agent responsible for the observed activity.     

Inhibitory effect of GA3 on the development of thidiazuron-induced somatic embryogenesis in geranium (Pelargonium xhortorum Bailey) hypocotyl cultures

Somatic embryogenesis in geranium (Pelargonium xhortorum Bailey cv Scarlet Orbit Improved) can be achieved by incubating hypocotyl explants on MS medium supplemented with thidiazuron (TDZ; 10 M for 3 days followed by subculture on medium devoid of any plant growth regulators. The presence of gibberellins (GAs) during both the induction and expression phases of embryogenesis was significantly detrimental to somatic embryo formation on the hypocotyl explants. The addition of the GA-synthesis inhibitors paclobutrazol, uniconazole or ancymidol during the period of growth and differentiation of somatic embryos increased the number of somatic embryos formed on each explant. However, paclobutrazol added during the period of induction had no significant influence on somatic embryo formation. Results suggest that both exogenously supplied as well as endogenous GAs play a role, albeit a negative one, on somatic embryogenesis of geranium.Abbreviations MS Murashige and Skoog (1962) medium - MSO basal medium devoid of any plant growth regulator - TDZ N-phenyl-N1,2,3-thidiazol-5-ylurea (thidiazuron)     

香叶油的化学成分

为了探讨不同产地香叶油的香气特徵,我们对云南省昆明、玉溪、石屏、宾川产香叶油和法国波尔蓬,埃及产香叶油的化学成分用Finnigan-4510型气相色谱/质谱/计算机联用方法进行了定性、定量分析,共分离鉴定了35个成分(见表2)。 分析结果表明:云南产香叶油的香气成分主要由香茅醇,甲酸香茅酯,香叶醇,玫瑰醚构成;而法国、埃及产香叶油的香气成分则主要由香叶醇,甲酸香叶酯,香茅醇,甲酸香茅酯和芳樟醇构成。二者具有不同的格调和香气特徵。     

Effects of Na(2)SO(3) on the activities of antioxidant enzymes in geranium seedlings

This study investigated the effects of Na(2)SO(3), which releases SO(2) in apoplastic water, on the growth of geranium seedlings and on the activities of various antioxidant enzymes including peroxidase. Sodium sulfite (Na(2)SO(3)) addition both inhibited primary root growth and stimulated lateral root growth of the seedlings respectively. In addition, the contents of chlorophyll and Rubisco protein of the seedlings were greatly reduced with Na(2)SO(3) treatment. Total peroxidase activities of the seedlings also increased proportionally with the amount of Na(2)SO(3), this presumably correlating with oxidative stress levels. Notably, about an 8-fold enhancement of total peroxidase activity occurred in seedlings treated with 60 nM Na(2)SO(3) at pH 4.0. This enhancement of total peroxidase activity was mainly due to the increase of a strong cationic isoperoxidase, strong anionic isoperoxidase and neutral isoperoxidase activities. The strong cationic isoperoxidase from geranium seedlings was found to be the same enzyme as PC3 from geranium callus in terms of its physicochemical and catalytic properties. Moreover, the activities of superoxide dismutase and glutathione reductase were greatly enhanced with Na(2)SO(3) treatments at pH 4.0 without significant alteration of catalase activity. These results suggest that Na(2)SO(3) exposure, activities the plants defense mechanism against the reactive oxygen species generated.     

Differential costs of reproduction in females and hermaphrodites in a gynodioecious plant

Background and Aims

Plants exhibit a variety of reproductive systems where unisexual (females or males) morphs coexist with hermaphrodites. The maintenance of dimorphic and polymorphic reproductive systems may be problematic. For example, to coexist with hermaphrodites the females of gynodioecious species have to compensate for the lack of male function. In our study species, Geranium sylvaticum, a perennial gynodioecious herb, the relative seed fitness advantage of females varies significantly between years within populations as well as among populations. Differences in reproductive investment between females and hermaphrodites may lead to differences in future survival, growth and reproductive success, i.e. to differential costs of reproduction. Since females of this species produce more seeds, higher costs of reproduction in females than in hermaphrodites were expected. Due to the higher costs of reproduction, the yearly variation in reproductive output of females might be more pronounced than that of hermaphrodites.

Methods

Using supplemental hand-pollination of females and hermaphrodites of G. sylvaticum we examined if increased reproductive output leads to differential costs of reproduction in terms of survival, probability of flowering, and seed production in the following year.

Key Results

Experimentally increased reproductive output had differential effects on the reproduction of females and hermaphrodites. In hermaphrodites, the probability of flowering decreased significantly in the following year, whereas in females the costs were expressed in terms of decreased future seed production.

Conclusions

When combining the probability of flowering and seed production per plant to estimate the multiplicative change in fitness, female plants showed a 56 % and hermaphrodites showed a 39 % decrease in fitness due to experimentally increased reproduction. Therefore, in total, female plants seem to be more sensitive to the cost of reproduction in terms of seed fitness than hermaphrodites.     

Floral symmetry is associated with flower size and pollen production but not insect visitation rates in Geranium robertianum (Geraniaceae)

The degree to which fine‐scaled variation in floral symmetry is associated with variation in plant fitness remains unresolved, as does the question of whether floral symmetry is in itself a target of pollinator‐mediated selection. Geranium robertianum (Geraniaceae) is a broadly distributed species whose five‐petaled flowers vary widely with respect to their degree of rotational asymmetry. In this study, we used a naturally occurring population of plants to investigate whether floral rotational asymmetry and leaf bilateral symmetry were phenotypically correlated with a series of fitness‐related traits, and also used an experimental array with model flowers to investigate the preference of insect visitors for varying degrees of floral size and symmetry. We found that leaf asymmetry was not associated with any of the phenotypic traits measured, and that the degree of floral rotational asymmetry was strongly associated with decreased flower size and decreased pollen production. Our experimental arrays showed that insect visitors did not discriminate among model flowers on the basis of size or symmetry alone; however, insect visitors preferentially visited smaller, symmetric model flowers over larger, severely asymmetric model flowers. Taken together, our results suggest that floral and leaf symmetry in G. robertianum are not likely strong indicators of phenotypic quality, and that floral symmetry is unlikely to be a target of pollinator‐mediated selection. However, the relationship between floral asymmetry and pollen production may provide a role for fecundity selection on symmetry in this species. These data importantly add to the growing literature on the adaptive nature of floral symmetry in the wild.     

中国老鹳草属新分类群

本文发表了老鹳草属二新变种,一新组合变种,即复花鼠掌老鹳草Gerauium sibiricum L.var.multiflorum Z.H.Lu;白河块根老鹳草Geranium dahuricum DC.var.baiheense Z.H.Lu et Y.C.Zhu和伏毛绒背老鹳草Geranium vlassovianum Fisch.ex DC.var.hattai(Nakai)Z.H.Lu。     

HPLC法测定3种老鹳草药材中没食子酸和柯里拉京的含量

目的：建立老鹳草、野老鹳草、牻牛儿苗中没食子酸、柯里拉京含量测定方法.方法：采用HPLC法,色谱条件：色谱柱为Diamonsil C18 （2）色谱柱（150 mm×4.6 mm,5μm）;流动相为乙腈-0.1％磷酸梯度洗脱;流速为1.0 mL/min;检测波长为274 nm;柱温为25℃.结果：没食子酸和柯里拉京的线性范围分别是：0.2024μg～2.024 0 μg（r =0.999 6）、0.126 0 ～2.520 0μg（r =0.999 2）,平均回收率分别是97.4％（RSD=1.4％）、96.7％（RSD=0.9％）.结论：本法简便、准确、重复性好,可用于老鹳草药材的质量评价.     

草地老鹳草一新变型——白花草地老鹳草

描述了老鹳草属草地老鹳草的一个新变型即白花草地老鹳草,该变型与原变型的区别在于变型的花冠为白色。