Role Of Phenolic Compounds Research Articles

Phenolic Compounds in Needles of Norway Spruce Trees in Relation to Novel Forest Decline. II. Studies on Trees from Two Sites in Middle Western Germany

Abstract The content of several phenolic compounds in needles of 20- to 30-year-old Norway spruce trees (Picea abies) was measured using HPLC. The results of two forestry sites in middle western Germany are reported in this paper. They are part of a research programme on novel forest decline which was carried out in various regions of Germany. Distinct amounts of picein, catechin, piceatannol glucoside, and other phenolic compounds were detected in the studied spruce needles. Additionally, their contents changed in relation to damage. Some compounds, especially catechin, showed increased levels in the needles of the damaged trees compared to the undamaged ones. Here, the values for the undamaged trees of the different sites were similar. Concerning the changes in picein contents, however, there was a great difference between the sites. p-Hydroxyacetophenone was detected in very low amounts only and did not correlate with damage. These results are compared with earlier findings from another site that shows severe damage. The role of phenolic compounds as indicators of tree damage is discussed.

Role of phenolic compounds in the antialgal activity of barley straw

Barley straw decomposing in well-aerated water releases a substance(s) that inhibits algal growth. Phenolic compounds are toxic to algae but are unlikely to be present in sufficient quantities to account for the extended antialgal action of straw. However, straw is antialgal under conditions that may promote oxidation of phenolic hydroxyl groups to quinones; tannins are antialgal under similar conditions. The toxicity of authentic quinones towardsMicrocystis is confirmed; the quinones are some 10(3) times more antialgal than phenolic acids. The possibility that oxidized lignin derivatives may be involved in straw toxicity towards algae is discussed.

Flavone photoreactivity. UV-induced reactions in organic solvents and micellar systems

Flavonoid photochemistry is a subject of interest in studies dealing with the role of phenolic compounds as screening pigments in plants. In order to contribute to the understanding of the processes involved in the interaction between flavonoids and UV radiation, we have studied UV-induced flavone photodegradation in both organic solvents and micellar systems. The results obtained show that flavone photosensitivity depends on the characteristics of the reaction environment and is influenced by the medium polarity and the charges on the micellar surface. Qualitative and quantitative differences in the photodegradation products were demonstrated by high performance liquid chromatography (HPLC) analysis.

The role of phenolic compounds and nutrients in determining food preference in greater snow geese.

We tested Buchsbaum's hypothesis that food palatability in geese is determined by a hierarchy of feeding cues among which deterrent secondary metabolites (mostly phenols) have a primary role (Buchsbaum et al. 1984). In preference tests, greater snow goose feeding was slightly depressed when grass was sprayed with ferulic acid but not when grass was sprayed with p-coumaric and tannic acids. Extracts of Timothy grass, red clover or alfalfa sprayed on grass also failed to depress goose feeding. In a multifactor experiment, phenol and protein content and height of grass were manipulated simultaneously. When ferulic acid was sprayed, protein and phenol content interacted in determining goose feeding preferences; protein content had no effect in the absence of phenol but did have an effect when phenol was added. When tannic acid was used in a similar experiment, results were inconclusive because of a significant and complex interaction between protein content and height of grass. Our results generally failed to support Buchsbaum's hypothesis that phenol content of plants has a primary role in determining food preference in geese. Protein content of plants seemed to be a more important factor.

Roles of phenolic compounds on micropropagation of juvenile and mature clones of Sequoiadendron giganteum: Influence of activated charcoal

The beneficial influence of activated charcoal (AC) (20 g l −1), added to the basal culture medium, was noted for in vitro growth and further rooting of microcuttings collected from juvenile clones of Sequoiadendron giganteum. During the elongation phase on the medium containing AC, the growing upper part of the juvenile clone microcuttings contained less polyphenols than the lower part, while this difference was not observed in mature material. Plantlets growing on AC-free medium had almost identical polyphenol levels, which greatly increased after the seventh week of culture both in the tissues and the medium. The effect of AC on microcutting growth as well as the significance of polyphenols for micropropagation are discussed.

The susceptibility of plants to Agrobacterium: A discussion of the role of phenolic compounds

An extensive literature survey of the host-range of Agrobacterium-induced neoplasms has revealed that highly susceptible plant families are accumulators of polyphenolics, whereas families assumed to be non-sensitive to the pathogen seem to lack this property. These and other results might indicate that polyphenolics play a role in the host-pathogen relationship of Agrobacterium-induced neoplasms. This hypothesis will be discussed in the light of the present knowledge of crown gall/hairy root induction and progress in plants.

Binding of nitrite-N on polyphenols during nitrification

The conversion of substantial amounts of ammonia nitrogen into organic nitrogen as a direct result of nitrification at neutral pH-values, was monitored in soil suspensions amended with ammonium nitrogen. The influence of the chemolithotrophic nitrifying bacteria was verified by applying nitrapyrin as a selective inhibitor in control experiments. In addition, the role of phenolic compounds was examined by adding α naphthol. The factors influencing the nitrification processi.e. pH, NH4+−N, NO2−−N, NO3−−N were measured during a 60 days incubation period. Nitrification started to be active after 5 and 10 days in the normal and the naphthol spiked soil suspensions respectively; it was inhibited in the nitrapyrin controls. Parallel with nitrification, formation of organic nitrogen was observed. The humic matter fractions were extracted and analyzed by I.R. spectroscopy which revealed the valence vibration ranges of nitro and nitroso groups fixed in different positions on aromatic compounds, both for normal and naphthol spiked samples. High resolution gas chromatography combined with mass spectroscopic analysis indicated the formation of nitrosonaphtholes. In addition a novel organic nitro compound was identifiedi.e. an azido nitro benzene. No nitrogen was fixed in the samples treated with nitrification inhibitor. A mechanism for the fixation of nitrite nitrogen during nitrification is proposed.

THE DEVELOPMENT AND ULTRASTRUCTURE OF ECTOMYCORRHIZAS

SummaryAn ultrastructural study was made of the interactions between Suillus grevillei (Klotzsch) Sing. and 11 species of ectomycorrhizal hosts in aseptic culture in the absence of glucose. No mycorrhizas were formed between S. grevillei and Betula pubescens Ehrh., Allocasuarina inophloia (F. Muell. & F. M. Bail.) L. Johnson, Picea sitchensis (Bong.) Carr., Picea abies (L.) Karst. Alnus glutinosa (L.) Gaertn. or Pinus nigra Arnold, although the fungus grew in the rhizosphere of some of these and in P. nigra it penetrated and killed adjacent epidermal cells. Mycorrhizas were formed with Larix kaempferi (Lamb.) Carr., Larix decidua Mill, Pinus sylvestris L. and Pseudotsuga menziesii (Mirb.) Franco. However, ultrastructural changes in the host‐fungus interface of associations with the latter two hosts suggest that in both cases the symbionts were not entirely compatible. The role of phenolic compounds in ectomycorrhizal compatibility and specificity is discussed.

The role of phenolic compounds and other plant constituents in feeding by Canada geese in a coastal marsh.

We have assessed the relative importance of phenolic compounds, other secondary metabolites, and gross nutrient levels as feeding cues to Canada geese. Phenolic content was the most significant constituent influencing feeding selection by geese. Nutrient content had little or no effect on feeding selection.Correlative data showing the negative influence of plant phenolics on food choices by wild geese were supported by feeding preference tests. Extracts of unpalatable plants inhibited feeding by captive geese relative to extracts of palatable plants. In high phenolic plants, the phenolic containing methanol extract was more inhibitory than extractions made with petroleum ether. In a relatively low phenolic, unpalatable plant, an inhibitory factor was extractable in petroleum ether, indicating that for this species, another class of deterrents was involved. Preference tests with individual secondary metabolites showed that tannic acid and quebracho tannin were very effective in inhibiting feeding by geese and phenolic acids were slightly inhibitory, but a sesquiterpene lactone was not deterrent. These results point out the primacy of some secondary metabolites in determining food choices by geese.

The Possible Role of Phenolic Compounds in Resistance of Horticultural Crops to Dematophora necatrix Hartig

AbstractCrops e. g., pecan, persimmon and passionflower, which show resistance to the fungus Dematophora necatrix, the causal agent of white root rot disease, contain phenolic compounds which inhibit its growth. Roots of resistant crops contain higher concentrations of phenolic compounds than those of suceptible crops, e. g., apple, almond and peach.The fungus contains active polyphenoloxidase (PPO). The oxidation of phenols to quinones may decrease the inhibitory effect. Catechol, methylcatechol, hydroquinone and 8‐hydroxyquinoline significantly inhibited the growth of the fungus.In greenhouse experiments, seedlings were irrigated with, or dipped in, phenols. Catechol, methylcatechol and hydroquinone delayed the appearance of disease symptoms.

Tissue fixation and staining with osmium tetroxide: the role of phenolic compounds.

It has been postulated that phenol-containing areas of plant and animal tissues were osmiophilic, but proof of direct interaction between osmium tetroxide and phenolic materials, or the nature of such reactions, has been lacking. We find that, under conditions similar to those of normal tissue fixation, osmium tetroxide reacts rapidly with those phenols containing o-dihydroxy groups (including such species found in plant tissues) to give very stable chelate complexes. We conclude that these complexes are responsible for the observed electron-density in phenol-containing areas of tissue treated with osmium tetroxide, so that such phenols are indeed osmiophilic.

Relation between the composition and the acid-sensitivity of some cytochemical reactions of chloragosomes in the earthworm, Lumbricus terrestris L.

Parallel biochemical and cytochemical examinations of chloragosomes were made. Ethanol-HCl extract of delipidized chloragosome fraction contains phosphatides, metalloporphyrins, further on polyphenolic and aminophenolic compounds, probably related to flavonoids and pteridines, proved by UV-spectrophotometric and chromatographic methods. The last 2 compounds were separately extracted by 0.1 N HCl. Previous extraction of sections by 0.1 N HCl resulted in a significant decrease of sudanophilia and in a total abolishment of basophilia and argentophilia in chloragosomes while their eosinophilis and peroxidase reactions become mroe intensive compared with those of the control sections. The role of phenolic compounds in the sudanophilic, basophilic and argentophilic reactions and their masking effect for the eosinophilia and the peroxidase reaction were discussed in relation to the chemical organisation of chloragosomes. Relation of chloragosomes to the lysosomal matrix was suggested.

The Role of Phenolic Compounds in the Resistance of Tomato Cultivars to Verticillium albo‐atrum

The Role of Phenolic Compounds in the Resistance of Tomato Cultivars to <i>Verticillium albo‐atrum</i>

Studies on Wheat Stem Rust Resistance Controlled at the Sr6 Locus. I. The Role of Phenolic Compounds

Studies on Wheat Stem Rust Resistance Controlled at the Sr6 Locus. I. The Role of Phenolic Compounds

3.会報の訂正

3.会報の訂正

The Role of Phenolic Compounds in the Resistance of Potato Tuber Tissue to Infection by Phytophthora infestans

1. Potato tuber disks, 0.5mm thick, of a variety having a resistance gene (R) became susceptible when inoculated with a dense spore suspension of an incompatible race of Phytophthora infestans.2. Treatment of these susceptible disks with phenolic compounds, such as chlorogenic acid, guaiacol, hydroquinone, catechol and caffeic acid alone or in combination with ascorbic acid, restored their resistance. Ascorbic acid by itself also reduced spore production on treated disks at the same concentration as that of chlorogenic acid.3. Treatment with chlorogenic acid or ascorbic acid at concentrations that strongly reduced sporulation on disks infected by an incompatible race had little effect on disks infected by a compatible race of P. infestans.4. Toxicities of the phenolic compounds and ascorbic acid to the pathogen were weak as compared to their inhibitory action on fungal development in the disks infected by an incompatible race.5. It was concluded that common phenolic compounds (and possibly ascorbic acid when oxidized) which can be found in healthy plants constitute a part of the mechanism confining the invading parasite to the infected locus.6. Analyses of the phenolic compounds contained in the potato tuber tissue infeted by an incompatibe race suggested that they may be supplied from the adjacent tissue where phenolic synthesis may be accelerated.

Role of Phenolic Compounds in the Physiology of Plant Diseases and Disease Resistance

Role of Phenolic Compounds in the Physiology of Plant Diseases and Disease Resistance