Milan Baláž

Vesicular-arbuscular mycorrhiza of Calamagrostis villosa supplied with organic and inorganic phosphorus

Plants of Calamagrostis villosa were cultivated in nutrient solution alone or in association with a vesicular-arbuscular mycorrhizal (VAM) fungus Glomus etunicatum. They were supplied with two levels of inorganic phosphate (Pi; 0.1 or 1 mM) and with or without organic phosphate (dinatriumphenylphosphate, Po; 1 mM). Depression of growth and enhancement of root respiration of mycorrhizal plants in comparison with non-mycorrhizal plants were observed after 12 weeks of cultivation in a growth cabinet. Root colonization was not influenced by the higher phosphorus availability in contrast to the extraradical mycelium (ERM). The lengths of ERM hyphae both attached to the root surface and in the substrate were decreased substantially by higher phosphorus supply, irrespectively of its form.

Carbon nutrition of mature green orchid Serapias strictiflora and its mycorrhizal fungus Epulorhiza sp.

We studied the nutritional modes of the orchid Serapias strictiflora and its mycorrhizal fungus Epulorhiza sp. using the differences in carbon isotopic composition (δ13C) of C3 orchid and C4 maize tissues. We found that if cultivated in substrate lacking any organic compounds, the mycorrhizal extraradical mycelia (δ13C = −26.3 ± 0.2 ‰) developed well, despite being fully dependent on nutrition from orchid roots (δ13C = −28.6 ± 0.1 ‰). If the mycorrhizal fungus had additional access to and colonized decaying maize roots (δ13C = −14.6 ± 0.1 ‰), its isotopic composition (δ13C = −21.6 ± 0.4 ‰) reflected a mixture of biotrophy and saprotrophy. No statistically significant differences in δ13C of new storage tubers were found between Epulorhiza-associated orchids with (δ13C = -28.2 ± 0.1 ‰) and without access to maize roots (δ13C = −28.6 ± 0.2 ‰). We conclude that autotrophy is the predominant nutritional mode of mature S. strictiflora plants and that they supply their mycorrhizal fungus with substantial amount of carbon (69 ± 3 % of the fungus demand), even if the fungus feeds saprotrophically.

Mycorrhizas of Cephalanthera longifolia and Dactylorhiza majalis, Two Terrestrial Orchids

Dynamics of mycorrhizal colonization of two orchid species, rhizomatous Cephalanthera longifolia and tuberous Dactylorhiza majalis, was studied during two growing seasons, with special emphasis on the occurrence of collapsed pelotons. No complete lysis of pelotons in digestion cells was found. Mycorrhizal colonization of subterranean organs of both species was observed to take place even before aerial shoots developed, indicating that colonization is not restricted to leafy season, and was constantly present throughout, the growing seasons with no distinct coincidence with flowering or fruiting time. Mycorrhizal colonization of C. longifolia was patchy and of low degree (mean = 4.4%. SE = 0.3%). It occurred mostly in the distal parts of main roots, lateral roots and/or in isolated root parts. Intensity of mycorrhizal colonization of D. majalis was generally higher (mean = 12.1%, SE = 0.7%). Tubers lacked colonization except in the root-like extensions.

Searchable database of soil- and mycorrhiza-related scientific reports (DSM)

A database involving recent but mainly old soiland mycorrhiza-related scientific literature is being compiled on the basis of a collection of reprints stored in Laboratory of Fungal Biology, Institute of Microbiology, Czech Academy of Sciences, Videfiskfi 1083, CZ-142 20, Prague 4, Czech Republic. The database is intended for free (non-profit) public use. To date it contains a selection of approx. 8000 records of primary literature and is expanding. The authors of the database are fully open to discussion and suggestions on how to increase its quality. The database has been established using the CCRM SCIBASE program (ALMS, Prague) and a format compatible with Reference Manager. The main purpose of DSM is to offer an electronic searchable source of bibliographic data including articles published before the electronic data processing. DSM can be accessed using the following address: