Search results for "Cardenolide"
showing 10 items of 20 documents
Digitalis obscura cardenolides. Effect of macronutrient concentration and N source on growth and productivity of shoot-tip cultures
1997
Abstract Changes in nutrient medium formulation in terms of major salt concentration or N source significantly modified cardenolide production by Digitalis obscura (genotype T4) shoot-tip cultures. A positive correlation between morphogenetic responses, culture growth, and proliferative capacity on one side and metabolite biosynthesis on the other cannot be established. The final stages of microprogation, rooting, and acclimatization of D. obscura were improved by using paclobutrazol.
Seasonal cardenolide production and Dop5βr gene expression in natural populations of Digitalis obscura
2004
Productivity variations and seasonal fluctuations of cardenolides have been studied in 10 natural populations of Digitalis obscura distributed in three bioclimatic belts. Main cardenolides in D. obscura plants are those of the series A and such predominance (ca. 80-85%) over the series B metabolites is independent of the population studied or the degree of maturity of the leaves. Primary glycosides represent ca. 50-60% of total cardenolides; this percentage did not vary among populations or with the leaf age but increased in summer and decreased in winter. A correlation analysis between plant biomass and cardenolide content showed a positive relationship of these parameters, which, accordin…
Plant hormones and Agrobacterium tumefaciens strain 82.139 induce efficient plant regeneration in the cardenolide-producing plant Digitalis minor
2002
Summary Shoot formation in explants of Digitalis minor was achieved, through axillary bud proliferation and adventitious bud differentiation, by varying the amount and source of plant hormones. Shoot regeneration was also obtained after infection of D. minor with the wild-type Agrobacterium tumefaciens strain 82.139, which induced shooty tumours. These shoots were not transgenic, as revealed by nopaline assays and the use of a C58pMP90/T139GUS-INT strain harbouring the intron inactivated gusA gene. Plants were easily rooted and transplanted into the greenhouse. Shoot cultures of D. minor accumulated up to 226 μg cardenolides per g dry mass when cultured on agar-solidified medium. Cardenolid…
Micropropagation of juvenile and adultDigitalis obscura and cardenolide content of clonally propagated plants
1991
Cultures ofDigitalis obscura L. were established from axillary buds of mature plants or leaves of seedlings obtained under aseptic conditions. Explants were cultured on Murashige and Skoog medium containing benzyladenine and/or naphthaleneacetic acid. Shoot proliferation from axillary buds was not affected by seasonal fluctuations in the stock plants and increased relative to the cytokinin concentration, but auxin reduced the multiplication rate. Differentiation of somatic embryos and adventitious buds from cultured leaves required naphthaleneacetic acid alone or combined with benzyladenine, respectively. Cardenolide pattern and content of the regenerated plants were determined by high perf…
Relationships among soil characteristics, plant macronutrients, and cardenolide accumulation in natural populations of Digitalis obscura
2005
In the present study, we have investigated relationships among several soil parameters (pH, organic matter, total carbonate, macronutrients, electrical conductivity, cation-exchange capacity) and macronutrient and cardenolide contents in leaves of wild Digitalis obscura plants. Young and mature leaves and soil samples were collected in ten different areas, corresponding to three Mediterranean bioclimatic belts (thermo-, meso-, and supramediterranean belts). Soil and leaf macronutrient (N, P, K, Ca, and Mg) contents and leaf cardenolide contents were determined. Bioclimatic conditions influenced the development of D. obscura, biomass being lowest in plant populations of the supramediterranea…
Effects of Gibberellic Acid on Morphogenesis and Cardenolide Accumulation in Juvenile and Adult Digitalis obscura Cultures
1993
Summary Effects of gibberellic acid on morphogenesis and cardenolide accumulation in in vitro cultures of Digitalis obscura are reported. Cultures were established from hypocotyls or leaves of axenic seedlings and shoot tips of mature plants. Irrespective of the kind of explant, gibberellic acid by itself did not induce morphogenesis but modified those morphogenic responses promoted by auxins and/or cytokinins, always inhibited organogenesis and favoured both embryo formation and conversion into plants. Gibberellic acid did not significantly affect cardenolide content of plants regenerated from juvenile or mature D. obscura explants.
Cardenolides of Digitalis obscura: The effect of phosphate and manganese on growth and productivity of shoot-tip cultures
1997
Abstract Cardenolide composition of leaves from wild and micropropagated elite plants of Digitalis obscura (genotype T4) has been investigated and no qualitative differences were found among their major cardenolides (series A). All of the detected glycosides belong to the digitoxose-type cardenolides. Genins represented less than 2% of the overall content, while lanatoside A was the predominant cardenolide ( ca. 65%) in all samples. The cardenolide yield of micropropagated D. obscura plants depended on the age and development of the cultures, but productivity of long-term cultures (2 years) was quite similar to that of the parent plant. Changes in the concentrations of phosphate or manganes…
Cardenolide variation within and among natural populations of Digitalis obscura
1999
Summary Cardenolide content in 49 wild-growing Digitalis obscura plants from six natural populations on the Iberian Peninsula was determined by HPLC. Series A and B glycosides were the predominant cardenolides in all samples, but absolute values varied among and within populations. Hierarchic analysis of variance showed that the proportion of variation attributable to individuals was significantly higher than that attributable to population differences. Furthermore, analyses from greenhouse-grown plants, generated from seeds collected from selected parental genotypes, attributed nearly all the variability in cardenolide content to single plants. Some individual plants showed a leaf content …
Soil‐plant relationships, micronutrient contents, and cardenolide production in natural populations of Digitalis obscura
2004
The production of secondary metabolites by plants growing in natural populations is conditioned by environmental factors. In the present study, we have investigated the relationships among soil properties, micronutrients in soils and plants, and cardenolide production from wild Digitalis obscura (Scrophulariaceae) populations. Young and mature leaves and soil samples were collected in ten different populations, corresponding to three Mediterranean bioclimatic belts (Thermo-, Meso-, and Supramediterranean belts). Soil (total and EDTA-extractable) and leaf micronutrients (Fe, Mn, Zn, and Cu), and leaf cardenolide accumulation have been determined. Significant negative correlations were observ…
Factors affecting shoot proliferation and vitrification inDigitalis obscura cultures
1992
Variations of composition and consistency of the culture medium and time of exposure to growth regulators were assayed to optimize normal caulogenic response ofDigitalis obscura hypocotyls cultured in vitro. The effects of the culture conditions on physiologic changes related to vitrification of the regenerated plants were also investigated. Liquid medium increased the bud-forming capacity of the explants but induced buds failed to develop into shoots and showed symptoms of vitrification. On agar-solidified media, maximum multiplication rates were achieved with 0.7% agar. Increasing agar concentration reduced vitrification but lowered the propagation rate. Changes in the strength of the mac…