Revealing the reviving secret of the white dead nettle (Lamium album L.)

Lamium album, commonly known as white dead nettle or non-stinging nettle is a flowering herbaceous plant, native throughout Europe, Western Asia and North Africa. From ancient times this plant has been endowed with revival, curative and culinary virtues. In the past, in the traditional and folk medicine white dead nettle has been used mainly for its anti-inflammatory, astringent and anti-septic activity. Nowadays significant amount of knowledge on the efficacy of extracts and raw material of L. album is accumulated and a number of health-related beneficial activities have been scientifically proven. In vitro analyses conducted in various model systems have demonstrated antiviral, antimicrobial, antioxidant, anticancer, cytoprotective, wound healing and other important pharmacological effects. The present review summarizes the recent information on the phytochemical features of this pharmacologically important species. The findings on the chemical composition, biological activities and the pharmacological properties underlying the revival secret of white dead nettle are described and discussed in the view of potential applications for treatment of human diseases. Trends for further research are outlined.     

Intraspecific variation in fruit size and shape in Corema album (Ericaceae) along a latitudinal gradient: from fruits to populations

Plant trait variation can be the result of environmental variability, developmental instability, and plasticity, although it can also arise from previous selective pressures on fruit traits themselves or directly on their variation. We aimed to quantify fruit size and shape variability at within‐plant, among‐plant, among‐population, and among‐year levels. For 2 years, we measured fruit size and shape along the geographical range of Corema album, aiming to determine whether (1) the population level among‐plant variation is lower than within‐plant and among‐population variation and (2) the ratio of within‐plant to among‐plant variation follows a latitudinal pattern. Levels of fruit variation were in accordance with the reported mean levels for reproductive organs. Most variance concentrated on within‐ and among‐individual levels for size, showing higher values for among‐individual variation in fruit shape. Although fruit size retained important variation among populations, this source of variance was negligible for fruit shape. This difference could arise from contrasting mechanical or developmental constraints. Despite the marked climatic differences along the latitudinal range of the species, latitude did not affect the ratio of within‐ to among‐plant variation. We show that an analysis of the often‐disregarded sources of intraspecific variation can produce unexpected results that deserve further investigation.     

Cultivation, mineral nutrition and seed production of Catharanthus roseus (L.) G. Don in the temperate climate zone

The following aspects of Catharanthus roseus (L.) G. Don cultivation are covered in this chapter: climatic and soil requirements, agricultural measures, including propagation, sowing, planting, fertilization, irrigation and harvest date. The influence of these parameters on quality of herb material and alkaloid concentration is also discussed. Although tropical and subtropical zone have been reported as the most suitable for the cultivation of Catharanthus roseus, it seems to be possible to grow it also under other climatic conditions. However then, adequate conditions should be provided, according to the specific requirements of this species. Proper air temperature and humidity as well as sufficient soil moisture during growth, development and seed set are important factors for growing of Catharanthus roseus in the temperate zone. Albeit it may tolerate unfavourable environment conditions such as drought or salinity, its yield may be reduced considerably. Special attention has been paid in this paper to the effect of different ways of fertilization on alkaloid yield.     

Alkaloid production in Catharanthus roseus (L.) G. Don.

Analysis of 76 cell clones derived from one leaf of a periwinkle plant (Catharanthus roseus (L.) G. Don) showed the occurrence of Corynanthe-, Strychnos-, and Aspidosperma-type alkaloids. The majority of clones (62%) displayed compounds of all three types. Variation of the alkaloid spectra of the cell clones was low when compared to that found previously with serially subcultured callus and cell suspensions derived from different plants.NRCC # 19100     

Spectrophotometer-aided evaluation of cyanogenic potential in white clover (Trifolium repens L.)

In comparison with ordinary methods of colorimetric evaluation of cyanogenic potential based on visual evaluation of the alkaline picrate reaction, a spectrophotometer-aided method could be more accurate (since it determines the exact amount of hydrogen cyanide released by the plant material), and less time-consuming as it can be performed on bulk material rather than on a number of individual plants. Ten white clover populations were evaluated by a spectrophotometer-aided method and by two visual evaluation criteria. All methods indicated the presence of large variation between populations. Visual methods gave almost identical results and allowed only for the distinction between cyanogenic and substantially acyanogenic populations. The results were only moderately consistent with those obtained by the spectrophotometer-aided method, which could detect the presence of variation also between cyanogenic populations. The effects of various incubation times (from 4 to 48 h) and of the addition of β-glucosidase on hydrogen cyanide release were also investigated. Comparable results for ranking of populations could be obtained over a range of incubation times, but at least 24 h were needed for a reliable estimation of the hydrogen cyanide produced by plants. The addition of enzyme did not increase the released cyanide. The effect of season and/or conditions of evaluation was marked on mean cyanogenic potential but limited on ranking of populations. Copyright © 2000 John Wiley & Sons, Ltd.     

Isolation, genetic variation and expression of TIR-NBS-LRR resistance gene analogs from western white pine ( Pinus monticola Dougl. ex. D. Don.)

Western white pine ( Pinus monticola Dougl. ex. D. Don., WWP) shows genetic variation in disease resistance to white pine blister rust ( Cronartium ribicola). Most plant disease resistance (R) genes encode proteins that belong to a superfamily with nucleotide-binding site domains (NBS) and C-terminal leucine-rich repeats (LRR). In this work a PCR strategy was used to clone R gene analogs (RGAs) from WWP using oligonucleotide primers based on the conserved sequence motifs in the NBS domain of angiosperm NBS-LRR genes. Sixty-seven NBS sequences were cloned from disease-resistant trees. BLAST searches in GenBank revealed that they shared significant identity to well-characterized R genes from angiosperms, including L and M genes from flax, the tobacco N gene and the soybean gene LM6. Sequence alignments revealed that the RGAs from WWP contained the conserved motifs identified in angiosperm NBS domains, especially those motifs specific for TIR-NBS-LRR proteins. Phylogenic analysis of plant R genes and RGAs indicated that all cloned WWP RGAs can be grouped into one major branch together with well-known R proteins carrying a TIR domain, suggesting they belong to the subfamily of TIR-NBS-LRR genes. In one phylogenic tree, WWP RGAs were further subdivided into fourteen clusters with an amino acid sequence identity threshold of 75%. cDNA cloning and RT-PCR analysis with gene-specific primers demonstrated that members of 10 of the 14 RGA classes were expressed in foliage tissues, suggesting that a large and diverse NBS-LRR gene family may be functional in conifers. These results provide evidence for the hypothesis that conifer RGAs share a common origin with R genes from angiosperms, and some of them may play important roles in defense mechanisms that confer disease resistance in western white pine. Ratios of non-synonymous to synonymous nucleotide substitutions (Ka/Ks) in the WWP NBS domains were greater than 1 or close to 1, indicating that diversifying selection and/or neutral selection operate on the NBS domains of the WWP RGA family.     

Characterization of somatic embryogenesis in sandalwood (Santalum album L.)

In the synchronous embryogenesis system of sandalwood developed in our laboratory, we observed that the early events of differentiation from freshly induced callus (stage 0) are accomplished in three distinct stages viz., preglobular masses (stage 1), globular embryos (stage 2), and bipolar embryos (stage 3). Transition from stage 0 to 1 was accomplished using 2,4-D and involves a stage specific appearance of two polypeptides of 15 and 30 kDa molecular weight. A 24 kDa polypeptide that was detected as a marked band in extracts of primary callus was not detected in stages 1, 2, and 3. Further, the tissue level of a 50 kDa glycoprotein decreased during transition from stage 2 to stage 3. However, the levels of glycoproteins in the medium were markedly higher in stage 0 cultures compared to those in stage 1. The activities of a protein kinase, glycosidase, and xylanase increased markedly with progressing embryogenesis. Our observations suggest that in addition to being controlled at the level of stage-specific gene expression, somatic embryogenesis in sandalwood is also regulated at the level of controls on cell wall flexibility and posttranslational changes in the pool of preexisting proteins.     

Transporters expressed during grape berry (Vitis vinifera L.) development are associated with an increase in berry size and berry potassium accumulation

Potassium accumulation is essential for grapevine (Vitis vinifera L.) growth and development, but excessive levels in berries at harvest may reduce wine quality particularly for red wines. In addition to decreasing the free acid levels, potassium also combines with tartaric acid to form largely insoluble potassium bitartrate. This precipitates during winemaking and storage, resulting in an increase in wine pH that is associated with negative impacts on wine colour, flavour, and microbiological stability. For these reasons, a better understanding of potassium transport and accumulation within the vine and berries is important for producing fruit with improved winemaking characteristics. Here two genes encoding KUP/KT/HAK-type potassium transporters that are expressed in grape berries are described. Their function as potassium transporters was demonstrated by complementation of an Escherichia coli mutant. The two transporters are expressed most highly in the berry skin during the first phase of berry development (pre-veraison), with similar patterns in two grapevine varieties. The timing and location of expression of these transporters are consistent with an involvement in potassium accumulation in grape berries.     

Ecophysiology, growth timing and reproductive effort of three sexual foms of Corema album (Empetraceae)

Corema album is a dioecious shrub endemic of the Iberian Peninsula, growing in sandy coastal areas from the North of Galicia to Gibraltar in the South. Hermaphrodite individuals have been found in the southern populations of El Asperillo (Spain) and Vila Real de Santo Antonio (Portugal). In this paper, the role of hermaphroditic individuals in the driest populations of its biogeographical area is discussed and the trade-off between reproduction and vegetative growth in the three sexual forms is presented. Asperillo site where hermaphrodite individuals were more abundant was selected for this current study. The proportion of hermaphrodite individuals was 1–4%, and male/female sex ratio ranged from 0.9 to 1.1. Hermaphrodite plants had a low number of hermaphrodite inflorescences, in relation to the number of staminate inflorescences. Their ripe fruits were smaller than those of female plants. The reproductive effort was three times higher in female than in male or hermaphrodite plants. The observed interannual oscillation in vegetative elongation was not related to annual rainfall. However, differences existed in growth timing among the three sexual forms, related to the timing of peak investment in reproduction. These results suggest the existence of trade-offs between investment in reproduction and vegetative growth. There were significant differences in leaf water potential among the three sexual forms early in summer, with males showing the less negative and hermaphrodite the most negative potential values. The demand of water for fruit production may explain these differences. [Valdés B., Talavera S. and Fernández Galiano E. (eds), 1987. Flora Vascular de Andalucía Occidental, vol. 1. Ketres Editora, Barcelona.]     

Chemical constituents of Physochlaina physaloides (L.) G. Don (Solanaceae)

The study of the whole plants of Physochlaina physaloides (L.) G. Don. has led to the isolation of eight alkaloids (1–6, 18, and 25), fourteen flavonoids (9, 11–17, and 19–24), two coumarins (7 and 10), one iridoid (8). The structures of these compounds were identified spectroscopically, and nuclear magnetic resonance (NMR) data were compared with previously reported data. This is the first study to describe the isolation and identification of compounds 1–3, 7, and 10–25 in P. physaloides. The chemotaxonomic significance of these compounds in the genus Physochlaina and its closely related genera was discussed.     

Cell and tissue cultures ofCatharanthus roseus (L.) G. Don: a literature survey

The literature concerning the formation of secondary metabolites in cell and tissue cultures ofCatharanthus roseus has been reviewed. Several aspects involved in the formation of secondary metabolites are discussed; e.g. regulation of secondary metabolism, environmental factors influencing secondary metabolism, biosynthesis and enzymology of the products, analysis of product formation, immobilization of cultured cells and stability of cell lines. Some economical aspects of production processes are discussed.     

野生植物长春花的营养成分

对野生植物长春花的营养成分进行了分析 ,结果表明 ,长春花中含有多种营养成分 ,其中至少含有 17种氨基酸。为开发利用植物资源提供了科学依据     

长春花组织培养条件的最优化

确定出长春花的愈伤组织诱导条件。优化长春花的组织培养的外植体、消毒方法、激素的种类和配比。叶柄作为诱导培养的外植体,2．5％有效氯的次氯酸钠消毒15min-20min,2,4－D：Kt＝2－3．5ppm:1ppm的激素诱导下11d诱导出生长良好、呈疏松颗粒状的愈伤组织。     

The calcium nutrition of bambara groundnut (Vigna subterranea (L.) Verdc.)

Iron chlorosis induced by Fe-deficiency is a widespread nutritional disorder in many woody plants and in particular in grapevine. This phenomenon results from different environmental, nutritional and varietal factors. Strategy I plants respond to Fe-deficiency by inducing physiological and biochemical modifications in order to increase Fe uptake. Among these, acidification of the rhizosphere, membrane redox activities and synthesis of organic acids are greatly enhanced during Fe-deficiency. Grapevine is a strategy I plant but the knowledge on the physiological and biochemical responses to this iron stress deficiency in this plant is still very poor. In this work four different genotypes of grapevine were assayed for these parameters. It was found that there is a good correlation between genotypes which are known to be chlorosis-resistant and increase in both rhizosphere acidification and Fe^III reductase activity. In particular, when grown in the absence of iron, Vitis berlandieri and Vitis vinifera cv Cabernet sauvignon and cv Pinot blanc show a higher capacity to acidify the culture medium (pH was decreased by 2 units), a higher concentration of organic acids, a higher resting transmembrane electrical potential and a greater capacity to reduce Fe^III-chelates. On the contrary, Vitis riparia, well known for its susceptibility to iron chlorosis, fails to decrease the pH of the medium and shows a lower concentration in organic acids, lower capacity to reduce Fe^III and no difference in the resting transmembrane electrical potential. H Marschner Section editor     

NMR metabolomics of berry quality in sea buckthorn (Hippophae L.)

Sea buckthorn (Hippophae L.) is a woody perennial shrub or small tree whose berries are rich in bioactive compounds with powerful nutritional and medicinal properties. Untargeted ¹H nuclear magnetic resonance (NMR) spectroscopy and principal component analysis (PCA) were used to characterize the metabolic profile of berry quality. There was strong separation in the NMR signal intensity of bioactive compounds between pulp and seeds, such as amino acids [gamma-aminobutyric acid (GABA), aspartate, glutamate, theanine, and proline], organic acids (citrate, succinate, malate, acetate, quinate, and heriguard), and carbohydrates (sucrose, fructose, glucose, and melibiose). Sea buckthorn cultivars could be clearly separated into two groups using principal component analysis (PCA) based on NMR spectroscopy of bioactive compounds in the pulp and seeds. Several metabolic compounds such as sugar, organic acids, and amino acids could serve as biomarkers for prediction of berry quality and for classification of germplasm collections. This dataset provides potential information concerning the mechanisms of berry quality formation and contributes to increasing the breeding efficiency of sea buckthorn quality improvement.     

Shoot regeneration and somatic embryogenesis from needles of redwood (Sequoia sempervirens (D.Don.) Endl.)

A rapid and effective system of somatic embryogenesis and organogenesis from the in vitro needles of redwood (Sequoia sempervirens (D.Don.) Endl.) had been established. The influences of plant growth regulators (PGRs) and days of seedlings in vitro on adventitious bud regeneration and somatic embryogenesis were studied. The process of somatic embryo formation was also observed. The results showed that embryogenic callus was induced and proliferated on Schenk and Hildebrandt (SH) medium with BA (0.5 mg/l), KT (0.5 mg/l) and IBA (1.0 mg/l). SH medium containing BA (0.5 mg/l), KT (0.2 mg/l) and IBA (0.2 mg/l) effectively promoted adventitious bud regeneration. The highest frequency (66.3%) of direct somatic embryogenesis was obtained in the combination of BA (0.5 mg/l) and IBA (0.5 mg/l). The optimal days of seedling in vitro for adventitious bud and somatic embryogenesis were 30 days and 30–40 days, respectively. The developments of somatic embryos were similar to that of zygotic embryogenesis. The result of histocytological studies indicated that proteins were gradually accumulated in the process of somatic embryo formation and there were two peaks of starch grains accumulation that one was in the embryogenic callus and the other was in the globular embryos. These results indicated that starch and protein were closely related with the energy supply and the molecular base of somatic embryogenesis, respectively.     

Cultural conditions affect somatic embryogenesis in Catharanthus roseus L. (G.) Don

We established an efficient plant regeneration system for Catharanthus roseus L. (G.) Don through somatic embryogenesis. Embryogenic callus was induced from hypocotyl of seed germinated in vitro. Somatic embryogenesis in Catharanthus has been categorized into three distinct stages: (1) initiation and proliferation of embryo; (2) maturation, and; (3) germination or plantlet conversion. Beside plant growth regulators, various stages of embryogenesis were screened for their response to a wide variety of factors (pH, gelrite, light, sugar alcohols, polyethyleneglycol and amino acids), which affect embryogenesis. All of the tested factors had a small to marked influence on embryogeny and eventual conversion to plantlets. The plantlets were acclimatized successfully in a greenhouse. To our knowledge, this is the first report describing a detailed study of various cultural factors which regulate embryogenesis in C. roseus. The results discussed in this paper may be used in mass propagation to produce medicinal raw material, and the embryo precursor cells could be used in genetic modification programmes that aim to improve the alkaloid yield as well.