Teresa Anielska

Establishment of arbuscular mycorrhizal plants originating from xerothermic grasslands on heavy metal rich industrial wastes–new solution for waste revegetation

Industrial waste substrata, rich in heavy metals, are poorly suited for plant growth. Efforts are made to establish an appropriate plant cover to reduce erosion and further contamination. Grasses are the usual solution, as they grow fast, thrive on poor substrata and have well-developed root systems. Some of them are also highly dependent on mycorrhizal symbiosis that supports their growth especially on poor and polluted soils. However, the commercially available grasses often meet a lack of well established mycorrhiza on the site and the introduced plant populations dramatically decrease with time, despite large financial input including covering the substratum with soil and intensive watering. The aim of this paper was to select proper plants together with mycorrhizal fungi that could accelerate the establishment of the vegetation and improve its diversity under these extreme conditions, minimizing the financial costs of the reclamation (no use of soil layering and watering). The experiments were carried out under field and laboratory conditions. The plant seeds used originated from dry calcareous grasslands. The seeds were germinated under field conditions or in pots filled with soil supplemented with substratum from the industrial wastes. The seedlings were inoculated with AM fungi and introduced on the field plots a few weeks after germination. The inoculum consisted of either crude inoculum harvested from the dry calcareous grasslands or strains originating from polluted areas. Plants colonized by mycorrhizal fungi established well in the experimental plots. The results suggest that inocula from dry calcareous grasslands are potentially useful in revegetation of industrial wastes. Although in several cases the photosynthetic activity of plants was lower than at the natural sites, almost all plants survived and formed seeds. In all experiments the plant vitality was estimated on the basis of chlorophyll a fluorescence and was useful to show differences between waste substrata, inocula and coexisting plant species. The interactions between mycorrhizal and non-mycorrhizal plants were studied under greenhouse conditions and at least no negative effect of this coexistence was found.

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

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 fungi alter thymol derivative contents of Inula ensifolia L.

Individuals of Inula ensifolia L. (Asteraceae), a valuable xerothermic plant species with potential therapeutic value, were inoculated under laboratory conditions with different strains of arbuscular mycorrhizal fungi (AMF): (1) Glomus intraradices UNIJAG PL-Bot, (2) G. intraradices UNIJAG PL-Kap, (3) Glomus clarum UNIJAG PL13-2, and (4) AMF crude inoculum from natural stands of I. ensifolia. We found AMF species specificity in the stimulation of thymol derivative production in the roots of I. ensifolia. There was an increase in thymol derivative contents in roots after G. clarum inoculation and at the same time the decreased production of these metabolites in the G. intraradices treatments. Moreover, no correlation between the extent of AMF colonization and the effects of the fungal symbionts on the plant was observed. A multilevel analysis of chlorophyll a fluorescence transients (JIP test) permitted an evaluation of plant vitality, expressed in photosynthetic performance index, influenced by the applied AMF strains, which was found to be in good agreement with the results concerning thymol derivative production. The mechanisms by which AMF trigger changes in phytochemical concentration in plant tissues and their consequences for practice are discussed.

Mycorrhizal fungi modulate phytochemical production and antioxidant activity of Cichorium intybus L. (Asteraceae) under metal toxicity.

Cichorium intybus (common chicory), a perennial plant, common in anthropogenic sites, has been the object of a multitude of studies in recent years due to its high content of antioxidants utilized in pharmacy and food industry. Here, the role of arbuscular mycorrhizal fungi (AMF) in the biosynthesis of plant secondary metabolites and the activity of enzymatic antioxidants under toxic metal stress was studied. Plants inoculated with Rhizophagus irregularis and non-inoculated were grown on non-polluted and toxic metal enriched substrata. The results presented here indicate that AMF improves chicory fitness. Fresh and dry weight was found to be severely affected by the fungi and heavy metals. The concentration of hydroxycinnamates was increased in the shoots of mycorrhizal plants cultivated on non-polluted substrata, but no differences were found in plants cultivated on metal enriched substrata. The activity of SOD and H2O2 removing enzymes CAT and POX was elevated in the shoots of mycorrhizal plants regardless of the cultivation environment. Photochemical efficiency of inoculated chicory was significantly improved. Our results indicate that R. irregularis inoculation had a beneficial role in sustaining the plants ability to cope with the deleterious effects of metal toxicity.

137Cs and 40K in fruiting bodies of different fungal species collected in a single forest in southern Poland.

Fruiting bodies of fungi belonging to more than 70 species were collected within a few thousand square meter area of one forest during 2006 and 2007. The soil profile was collected to check the cumulative deposition of (137)Cs, which was relatively high, equal to 64 +/- 2 kBq/m(2) (calculated for October 2006). The majority of this activity was in the first 6 cm. Fruitbodies were analyzed for radiocesium and (40)K by means of gamma-spectrometry. The highest (137)Cs activity was 54.1 +/- 0.7 kBq/kg (dry weight) for a sample of Lactarius helvus collected in 2006. The results for 2006 were higher than those for 2007. In a few cases the traces of short-lived (T(1/2) = 2.06 a) (134)Cs were still found in samples. The importance of mycorrhizal fungi for radiocesium accumulation is confirmed. The differences in activity among the species are discussed in relation to observations and predictions from previous studies, where the change in relative accumulation between fruiting bodies of different species was at least partially explained by the differences in the depth of the mycelium localization in a litter/soil system. It is concluded that in some cases, such as Boletus edulis and Xerocomus badius, this prediction is fulfilled and therefore this explanation confirmed.

ROLE OF MYCORRHIZAL FUNGI IN PHYTOREMEDIATION AND TOXICITY MONITORING OF HEAVY METAL RICH INDUSTRIAL WASTES IN SOUTHERN POLAND

The chapter summarizes research carried out within the last 15 years on the role of mycorrhizal fungi in phytoremediation of zinc wastes located in southern Poland. The impact of various technologies on tailing material toxicity was described and physico-chemical features of the wastes were characterized. Symbiotic fungi are an important component of soil microbiota. As shown in a range of studies, properly developed mutual symbiosis enhances the survival of plants in polluted areas by for instance improving nutrient acquisition and water relations, thus supporting the success of bioremediation. In addition, mycorrhizal fungi were found to play an important role in heavy metal detoxification and the establishment of vegetation in strongly polluted areas. Fungal strains isolated from old zinc wastes also decrease heavy metal uptake by plants growing on metal rich substrata, limiting the risk of increasing the levels of these elements in the food chain. The effectiveness of the bioremediation techniques depends on the appropriate selection of both the plant and the fungal partners. The experiments pointed out that plants conventionally introduced in such places disappear relatively soon, while those appearing during natural succession are better adapted to harsh conditions. Symbiotic partners selected on the basis of such research are often the best choice for future phytoremediation technologies. Moreover, mycorrhizas of different types are also helpful in tailing material toxicity monitoring.

Mycothallic/mycorrhizal symbiosis of chlorophyllous gametophytes and sporophytes of a fern, Pellaea viridis (Forsk.) Prantl (Pellaeaceae, Pteridales)

AbstractGametophytes of Pellaea viridis that appeared spontaneously on the surface of substratum originating from an ultramafic area were found to form mycothallic symbiosis with arbuscular mycorrhizal fungi (AMF) under laboratory conditions. In gametophytes and sporophytes grown with Glomus tenue, abundant arbuscule formation was observed at both stages. In gametophytes, the fungus was found in the region where the rhizoids are initiated. If G. intraradices was added to the soil, the gametophytes were colonised mostly by G. tenue, and roots of sporophytes were colonised by G. intraradices. The presence of AM fungi in both gametophytes and sporophytes of P. viridis resulted in the development of larger leaf area and root length of the sporophyte. The analysis of gametophytes from the Botanical Garden in Krakow (Poland) showed that cordate gametophytes of Pteridales, namely Pellaea viridis (Pellaeaceae), Adiantum raddianum and A. formosum (Adiantaceae), were also mycothallic.

Metal uptake by xerothermic plants introduced into Zn-Pb industrial wastes.

The dusty surfaces of post-flotation wastes contain high concentrations of toxic compounds and spread widely if appropriate vegetation is not introduced. It has been previously established that effective restoration of such waste areas are best met by xerothermic, mycorrhiza-assisted plants (Turnau et al. Plant and Soil 305:267–280, 2008). The aim of the current study was to improve phytostabilisation practices by gaining insight into the elements uptake in plants after their change of habitat. Total Reflection X-ray Fluorescence (TXRF) was employed to evaluate element concentration in the leaves of 23 plant species growing in the wild and on Zn-Pb waste. Higher levels of heavy metals (Zn, Y, As, Pb, Cu) in plants from tailings were usually accompanied by increased Ca concentration, suggesting a possible role of this element in detoxification mechanisms. Also, when compared to grassland specimens, plants from the tailings, exhibited potassium-deficiency. Thus, K-supplementation of the waste substrata should be considered to improve plant growth. Among all the introduced plants, three grass species (Melica transsilvanica, Bromus inermis, Elymus hispidus) and one legume (Anthylis vulneraria) were the most suitable for phytostabilisation. Heavy metal-accumulating properties of Verbascum thapsus need further investigation.

Effects of genetic modifications to flax (Linum usitatissimum) on arbuscular mycorrhiza and plant performance

Although arbuscular mycorrhizal fungi (AMF) are known for their positive effect on flax growth, the impact of genetic manipulation in this crop on arbuscular mycorrhiza and plant performance was assessed for the first time. Five types of transgenic flax that were generated to improve fiber quality and resistance to pathogens, through increased levels of either phenylpropanoids (W92.40), glycosyltransferase (GT4, GT5), or PR2 beta-1,3-glucanase (B14) or produce polyhydroxybutyrate (M50), were used. Introduced genetic modifications did not change the degree of mycorrhizal colonization as compared to parent cultivars Linola and Nike. Arbuscules were well developed in each tested transgenic type (except M50). In two lines (W92.40 and B14), a higher abundance of arbuscules was observed when compared to control, untransformed flax plants. However, in some cases (W92.40, GT4, GT5, and B14 Md), the mycorrhizal dependency for biomass production of transgenic plants was slightly lower when compared to the original cultivars. No significant influence of mycorrhiza on the photosynthetic activity of transformed lines was found, but in most cases P concentration in mycorrhizal plants remained higher than in nonmycorrhizal ones. The transformed flax lines meet the demands for better quality of fiber and higher resistance to pathogens, without significantly influencing the interaction with AMF.

Arbuscular mycorrhiza improves yield and nutritional properties of onion (Allium cepa)

Improving the nutritional value of commonly cultivated crops is one of the most pending problems for modern agriculture. In natural environments plants associate with a multitude of fungal microorganisms that improve plant fitness. The best described group are arbuscular mycorrhizal fungi (AMF). These fungi have been previously shown to improve the quality and yield of several common crops. In this study we tested the potential utilization of Rhizophagus irregularis in accelerating growth and increasing the content of important dietary phytochemicals in onion (Allium cepa). Our results clearly indicate that biomass production, the abundance of vitamin B1 and its analogues and organic acid concentration can be improved by inoculating the plant with AM fungi. We have shown that improved growth is accompanied with up-regulated electron transport in PSII and antioxidant enzyme activity.