Search results for "HORTICULTURE"
showing 10 items of 1421 documents
Cell wall-degrading enzymes produced in vitro by isolates of Phaeosphaeria nodorum differing in aggressiveness
2000
The relationships between in vitro production of cell wall-degrading enzymes and aggressiveness of three Phaeosphaeria nodorum isolates were investigated. When grown in liquid medium containing 1% cell wall from wheat leaves as the carbon source, the isolates secreted xylanase, α-arabinosidase, β-xylosidase, polygalacturonase, β-galactosidase, cellulase, β-1,3-glucanase, β-glucosidase, acetyl esterase and butyrate esterase. Time-course experiments showed different levels of enzyme production and different kinetics between isolates. A highly aggressive isolate produced more xylanase, cellulase, polygalacturonase and butyrate esterase than did the two weakly aggressive isolates. Xylanase was …
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…
Effect of Ti(IY) on some indicators of physiological activity inCapsicum annuum, L.
1994
SummaryPaprika pepper (Capsicum annuum, L., cv. Negral) plants grown in a greenhouse were supplied Ti(IV) ascorbate through the roots or through leaves. Biomass production, peroxidase (donor: H2O, oxidoreductase; EC 1.11.1.7) activity, and malic acid, starch and chlorophyll concentrations were determined in different plant organs. It was observed that Ti increased the concentration of some of the metabolites studied and promoted both peroxidase activity and biomass production. The profitable effect of the Ti treatments could occur because they enhance the availability of other nutrients. This effect could be due to the low redox potential of the Ti+3/Ti+4 system that catalyzes the activity …
Acetogenins from Annona glabra seeds
1998
Abstract From the cytotoxic ethanol extract of Annona glabra seeds, a new mono-tetrahydrofuranic (mono-THF) acetogenin, glabranin, as well as pair of 22-epimer bis-THF acetogenins, were isolated by semipreparative HPLC. Four known mono-THF acetogenins with an identical threo/trans/threo relative configuration, annonacin, annonacinone, corossolin and corossolone, were found to be potent inhibitors of complex I of the mitochondrial respiratory chain.
Dammarane triterpenes of Salvia hierosolymitana
1990
Abstract Salvilymitone and salvilymitol, two new triterpenoids isolated from Salvia hierosolymitana , have been shown to be 7β,25-dihydroxy-(20 S ,24 R )-epoxydammaran-3-one and (20 S ,24 R )-epoxydammaran-3β,7α,25-triol, respectively. The absolute stereochemistry of these triterpenoids has been established by an X-ray diffraction analysis of a 25,26,27-trinor derivative obtained by degradation of both compounds. In addition, four previously known triterpenoids were isolated from the same source.
Ingenane and lathyrane diterpenes from the latex of Euphorbia canariensis
1997
The latex of Euphorbia canariensis yielded, in addition to five known ingenol esters, the ingenane derivatives ingenol 3-angelate 5,20-diacetate and 5-deoxyingenol 3-angelate 20-acetate, and the lathyrane derivatives 2,3-diepiingol 7,12-diacetate 8-benzoate, 2,3-diepiingol 7,12-diacetate 8-isobutyrate and 2-epiingol 3,7,12-triacetate 8-benzoate. The structures were established with the aid of spectroscopic methods, mainly NMR, and molecular mechanics calculations. They were also supported by the results of some chemical transformations.
Oxygenated germacranes from Santolina chamaecyparissus
1993
The polar fraction of an extract of Santolina chamaecyparissus ssp. squarrosa yielded six new germacrane derivatives and a novel seco-germacrane lactone. The structures have been derived from spectral data, X-ray diffraction and chemical correlations.
Influence of Nitrogen Content on Grape Non-Saccharomyces Glycosidic Activities
2019
This study investigated the influence of nitrogen content on both β-glucosidase and β-xylosidase activities from non-Saccharomyces yeasts. Enzymatic activities were induced by the presence of xylan polysaccharides in the medium. Results show that optimizing β-glucosidase and β-xylosidase enzymatic activities can be determined not only by sugar or ethanol content or pH, but also by the concentration of N in the medium. This is the first work studying the influence of N content on glycolytic enzymes produced by non-Saccharomyces yeasts.
A xyloglucan from persimmon fruit cell walls
1998
Persimmon (Diospyros kaki L.) fruit cell walls have been shown to contain a high proportion of xyloglucan. This hemicellulosic polysaccharide appears to play a crucial role in the softening process that accompanies fruit ripening. In the present work, xyloglucan from persimmon fruit cell walls was extracted, purified and chemically characterized from alkali-extracted hemicelluloses. Monosaccharide analysis of purified xyloglucan showed a molar ratio of Glc:Xyl:Gal:Fuc of 10.0:6.0:3.4:1.4. Linkage analysis showed a high proportion of terminal residues, indicating a low degree of polymerization of side-chains.
Morphogenic potential of mechanically isolated single cells from Digitalis obscura L. callus
1989
Calli from hypocotyl and root explants of Digitalis obscura L. showed regeneration of adventitious shoots, roots and embryos when transferred to Murashige & Skoog medium supplemented with cytokinins alone or in combination with auxins. Optimum shoot-bud formation was achieved in the presence of IAA and BA, while roots mainly appeared either in absence of growth regulators or with IAA and Kn. Embryo formation took place only in those combinations that included Kn. Embryo development was influenced by the type of auxin, and precocious germination occurred in media with NAA. Mechanically isolated cells from hypocotyl- and root-derived calli were plated in MS medium supplemented with several IA…