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At least 19 recordsLinked to original sources
PubMed2002

Photosynthetic responses to water deficit in six Mediterranean sclerophyll species: possible factors explaining the declining distribution of Rhamnus ludovici-salvatoris, an endemic Balearic species.

We sought to explain the declining distribution in the Balearic Islands of the endemic shrub Rhamnus ludovici-salvatoris R. Chodat, by comparing its photosynthetic response to drought with that of several widely distributed, competing Mediterranean species (R. alaternus L., Quercus ilex L., Pistacia lentiscus L., Q. humilis Mill. and P. terebinthus L.). All of the study species, except for the two Rhamnus species, avoided desiccation by rapidly adjusting their stomatal conductance at the onset of drought, and maintaining constant leaf relative water content. The two Rhamnus species showed desiccation-tolerant behavior; i.e., as drought progressed, their predawn leaf relative water content decreased simultaneously with stomatal closure. All four desiccation-avoiding species showed a significant positive correlation between leaf thermal dissipation (estimated by the fluorescence parameter NPQ (non-photochemical quenching)) and the de-epoxidation state of the xanthophyll cycle (DPS). The two Rhamnus species exhibited maximum DPS regardless of treatment, but only R. alaternus increased NPQ in response to drought. Rhamnus ludovici-salvatoris had a high ratio of photorespiration to photosynthesis and a low intrinsic water-use efficiency; traits that are likely to be unfavorable for plant productivity under arid conditions. It also had the lowest DPS and thermal dissipation among the six species. We conclude that the photosynthetic traits of R. ludovici-salvatoris account for its limited ability to compete with other species in the Mediterranean region.

Carbon Dioxide↗
PubMed2026

The complete chloroplast genomes of Rhamnus arguta Maxim. and R. parvifolia Bunge (Rhamnaceae).

The genus Rhamnus L. (Rhamnaceae) has high medicinal, ecological, and ornamental value, but its infrageneric classification remains unclear. Here, we sequenced, assembled, and annotated the complete chloroplast genomes of Rhamnus arguta and R. parvifolia using Illumina sequencing. Both plastomes exhibit the typical quadripartite structure, with lengths of 160,566 bp and 161,243 bp, containing 128 and 129 genes, respectively. Phylogenetic analyses support the monophyly of Rhamnus and its close relationship with Frangula. This study provides genomic resources for further phylogenetic and comparative studies within Rhamnaceae.

Chloroplast genome↗
PubMed2004

Critical stages in the recruitment process of Rhamnus alaternus L.

BACKGROUND AND AIMS: Rhamnus alaternus is a Mediterranean shrub commonly used in reforestation programs. Although several aspects of its reproductive biology have been studied, little is known about the importance of the different recruitment stages in the overall regeneration process of this species, which limits its proper use in Mediterranean forests and shrubland management. The aim of the present work was to quantify the importance of the different recruitment stages in the regeneration process of R. alaternus. METHODS: Two populations of Rhamnus alaternus on the island of Mallorca that differ in climatic conditions, type of habitat and sex ratio were studied. The importance of seed production, seed dispersal and predation, seedling emergence and seedling survival for the regeneration of this species were quantified. KEY RESULTS: In both populations, fruit set and fruit removal by animals were not critical stages, since almost half of the flowers became mature fruits and 90% of those were dispersed. Most seeds were deposited under female conspecifics (86 and 47%, at Lloret and Esporles, respectively), and very few were found in open inter-spaces (1 and 5%). Post-dispersal seed predation (mostly by ants and rodents) was very high in both populations. Seedling emergence took place during autumn and early winter and it ranged from 31 to 68% depending upon year and microhabitat. The majority of emerged seedlings died during the first year, mainly due to desiccation; such mortality was influenced by rainfall and differed among microhabitats (varying from 67 to 100%). The general spatial distribution of seed rain was concordant with the seedling emergence and survival pattern in both populations. CONCLUSIONS: The recruitment of Rhamnus alaternus appeared to be mainly limited by seed and seedling survival, regardless of the type of habitat in which the species is found.

Mediterranean Region↗
PubMed2001

In vitro anti-inflammatory effects of quercetin 3-O-methyl ether and other constituents from Rhamnus species.

The anti-inflammatory activities of the isolated flavonoids, quercetin 3-O-methyl ether (1), kaempferol (2), and quercetin (3), of Rhamnus nakaharai, and anthraquinone, frangulin B (4), of Rhamnus formosana, were assessed in vitro by determining their inhibitory effects on the chemical mediators released from mast cells, neutrophils, macrophages, and microglial cells. Compounds 1 - 3 strongly inhibited the release of beta-glucuronidase and lysozyme from rat neutrophils stimulated with formyl-Met-Leu-Phe/cytochalasin B (fMLP/CB). Compound 1 strongly inhibited superoxide anion formation in fMLP/CB or phorbol 12-myristate 13-acetate (PMA)-stimulated rat neutrophils. Compound 1 exhibited potent inhibitory effect on tumor-necrosis factor-alpha ( TNF-alpha) formation in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells while 1 and 4 showed potent inhibitory effects on TNF-alpha formation in LPS/IFN-gamma (interferon-gamma)-stimulated murine microglial cell lines N9.

Animals↗
PubMed2005

[Chemical constituents of the aerial parts of Rhamnus crenatus].

AIM: To study chemical constituents of the aerial parts of Rhamnus crenatus sieb. et zucc. METHODS: The chemical constituents were isolated by chromatographic methods and their structures were elucidated on the basis of spectral analysis. RESULTS: Five compounds were isolated and their structures were identified as crenatoside (1), torachrysone (2), emodin (3), emodin-1-O-beta-D-glucopyranoside (4) and beta-sitosterol (5) respectively. CONCLUSION: Compound 1 is a new compound and the others were isolated from Rhamnus crenatus for the first time.

Caffeic Acids↗
PubMed2003

Alteration in rhizosphere soil properties of afforested Rhamnus lycioides seedlings in short-term response to mycorrhizal inoculation with Glomus intraradices and organic amendment.

The reestablishment of autochthonous plant species is an essential strategy for recovering degraded areas under semiarid conditions. A field experiment was carried out to assess the short-term effect of two reafforestation methods involving mycorrhizal inoculation and compost addition on soil quality parameters and Rhamnus lycioides seedling growth. The nutrient content (NPK) and enzymatic activities (dehydrogenase, urease, protease-BAA, acid phosphatase and beta-glucosidase) increased and bulk density decreased in the rhizosphere soil with the organic amendment. Biomass C of rhizosphere soil increased by at least 240% with respect to the control soil after mycorrhizal inoculation and the combination of compost addition + mycorrhizal inoculation. Both mycorrhizal inoculation and composted organic residue addition increased R. lycioides seedling growth in the same proportion. In the short term, we conclude that the application of both reafforestation methods not only enhances the establishment of R. lycioides seedlings, but also improves soil quality.

Biomass↗
PubMed1994

Rhamnetin 3-p-coumaroylrhamninoside from Rhamnus petiolaris.

From the berries of Rhamnus petiolaris a new acylated flavonol glycoside was isolated and identified as rhamnetin 3-O-[3""-O-(p-coumaroyl)-alpha-L-rhamnopyranosyl(1-->3)- alpha-L-rhamnopyranosyl(1-->6)]-beta-D-galactopyranoside. Additionally, five known flavonol glycosides, rhamnetin, rhamnazin, quercetin and kaempferol 3-rhamninosides, and quercetin 3-rhamnoside were isolated.

Carbohydrate Sequence↗
PubMed1986

Hypotensive effect of Rhamnus lycioides extracts.

Intravenous administration of a lyophilized hot water extract and various organic solvent extracts of Rhamnus lycioides to normotensive anesthetized Wistar rats produced a lowering of systemic arterial blood pressure. Acute toxicity of the lyophilized extract was studied in mice by intraperitoneal injection. The phytochemical analyses revealed the presence of steroids-triterpenes, catechin tannins, flavonoids, sugars and resins.

Animals↗
PubMed1990

A hypotensive procyanidin-glycoside from Rhamnus lycioides ssp. lycioides.

A lyophilized hot water extract of the aerial parts of Rhamnus lycioides L. (Rhamnaceae) produced a lowering of systemic arterial blood pressure in normotensive anaesthetized Wistar rats. An activity-guided fractionation of the methanolic extract led to the isolation of a tetrameric procyanidin-glycoside which produced a clear dose-dependent hypotensive response (1.5-6 mg/kg i.v.). This principle was characterized using acid hydrolysis, thiolytic degradation and spectroscopic methods. It consisted of four flavanol units with a 2,3-cis configuration and with a O-beta-d-glucosylpyranoside function on the epicatechin terminal unit. The interflavan linkage was (4-8).

Animals↗
PubMed2005

Antifungal activity of Rubia tinctorum, Rhamnus frangula and Caloplaca cerina.

The results of a preliminary antifungal screening of the methanol extracts and the major anthraquinone aglycones, alizarin and emodin, of Rubia tinctorum and Rhamnus frangula in comparison with the antifungal activity of the anthraquinone-containing lichen Caloplaca cerina and its main secondary metabolite parietin are reported.

Antifungal Agents↗
PubMed1991

Flavonol and anthraquinone glycosides from Rhamnus formosana.

Two new flavonol triglycosides, and a new anthraquinone glycoside, have been isolated from the roots of Rhamnus formosana. These compounds have been characterized as rhamnazin 3-O-[alpha-L-rhamopyranosyl(1----4)-alpha-L-rhamnopyranosyl(1----6 )]-beta-D-galactopyranoside (rhamnazin 3-isorhamninoside), rhamnocitrin 3-O-isorhamninoside and 1,6,8-trihydroxy-3-methylanthraquinone 1-O-rhamnosyl(1----2)glucoside, respectively.

Anthraquinones↗