Optimization of culture conditions of Arnica montana L.: effects of mycorrhizal fungi and competing plants

Abstract

Arnica montana is a rare plant that needs special protection because of its intensive harvesting for medicinal purposes. The present work was aimed at finding optimal culture conditions for Arnica plants in order to enable their successful reintroduction into their natural stands. Plants were cultivated under controlled greenhouse conditions on substrata with different nitrogen (N) concentration. As Arnica is always colonized by arbuscular mycorrhizal fungi (AMF) in nature, a fact that has been overlooked in other similar projects, we, here, applied and tested different inocula. We found that they differed in their effectiveness, both in establishing symbiosis, assessed by the colonization parameters, and in improving the performance of Arnica, evaluated by the photosynthetic parameters derived from the fluorescence transients (JIP-test), with the inocula containing G. intraradices or composed of several Glomus strains being the most effective. The comparison was possible only on substrata with medium N, since high N did not permit the formation of mycorrhiza, while at low N, few nonmycorrhizal plants survived until the measurements and mycorrhizal plants, which were well growing, exhibited a high heterogeneity. Analysis of secondary metabolites showed clearly that mycorrhization was associated with increased concentrations of phenolic acids in roots. For some of the inocula used, a tendency for increase of the level of phenolic acids in shoots and of sesquiterpene lactones, both in roots and in shoots, was also observed. We also studied the interactions between A. montana and Dactylis glomerata, known to compete with Arnica under field conditions. When specimens from both species were cultured together, there was no effect on D. glomerata, but Arnica could retain a photosynthetic performance that permitted survivability only in the presence of AMF; without AMF, the photosynthetic performance was lower, and the plants were eventually totally outcompeted.

Arbuscular mycorrhizal symbiosis and active ingredients of medicinal plants: current research status and prospectives

“…Contents of these unique ingredients can be used as standards for the quality of medicinal plants, such as levels of limonene and carvone in dill (Kapoor et al 2002a), thymol in carum (Kapoor et al 2002a), geraniol and linalool in coriander (Kapoor et al 2002b), anethol in fennel (Kapoor et al 2004), sesquiterpene lactones in Arnica (Jurkiewicz et al 2010), and artemisinin in A. annua (Kapoor et al 2007;Chaudhary et al 2008;Huang et al 2011). Previous research has shown that the AM symbiosis can promote the production of specific secondary metabolites in specific medicinal plants.…”

“…Resisting malaria Kapoor et al 2007;Rapparini et al 2008;Chaudhary et al 2008;Awasthi et al 2011;Huang et al 2011 Echinacea purpurea Antibacterial and antiviral effects Araim et al 2009 Arnica montana Treating bruises, swellings and diseases of the mouth Jurkiewicz et al 2010 Inula ensifolia Diminishing inflammation and antiviral effect Zubek et al 2010 Artemisia umbelliformis Antibacterial and antiviral effects Binet et al 2011 Tagetes erecta Diminishing inflammation, treating cold and cough…”

“…The levels of other active ingredients in medicinal plants, such as phenolics in purple coneflower (Echinacea purpurea) (Araim et al 2009), phenolic acid in Arnica montana and Catharanthus roseus (Jurkiewicz et al 2010;Rosa-Mera et al 2011), sesquiterpenic acid in Valeriana officinalis (Nell et al 2010), and a thymol derivative in Inula ensifolia (Zubek et al 2010), are also promoted by the formation of AM symbiosis. However, some studies have shown that AM do not have positive effects on the composition of phenolic ingredients.…”

“…Jurkiewicz et al (2010) reported that inocula composed of different AM fungi differed not only in their effectiveness in establishing symbiosis and promoting growth of A. montana, but also in the degree to which they increased plant contents in phenolic acids and sesquiterpene lactones. Similar results have been obtained by several researchers.…”

Endophytic Streptomyces in the traditional medicinal plant Arnica montana L.: secondary metabolites and biological activity

“…The polyacetylenic molecules additionally provide an antifungal effect. Phenolic acids add an antioxidative facet (Rossetti et al 1984;Teuscher et al 2009;Jurkiewicz et al 2010;Pljevljakušić et al 2012). …”