Informace o publikaci



VESELÁ Barbora BALÁŽ Milan

Rok publikování 2012
Druh Článek ve sborníku
Konference MENDELNET 2012
Fakulta / Pracoviště MU

Přírodovědecká fakulta

Klíčová slova Orchidaceae; euh-ofication; mycorrhizal symbiosis; Serapias lingua
Popis Eutrofication is one of key factors affecting decline of orchid populations in nature. Although this phenomenon has been observed many times and is generally accepted, there is very little information about the mechanisms of eutrofication on terrestrial orchids of temperate or Mediterranean climatic zone. In principle, two modes of action may occur: direct toxic effect of higher nutrient content on orchids or their mycorrhizal fungi, and/or indirect effect mediated by altered competition with surrounding vegetation. I tested the significance of direct effect in a three-year lasting pot greenhouse experiment using Mediterranean orchid Serapias lingua. Indirect effect of eutrofication was excluded by omitting any co-cultivated plant species, eutrofication was simulated by the series of nutrient solutions. The most concentrated basic solution containing 6 mM N-NO3-, 2.4 mM N-NH4+, 2 mM P, 8 mM K, 2.6 mM Ca a 2 mM Mg was gradually diluted with distilled water in 1:1 ratio, in order to prepare 2, 4, 8, and 16x diluted treatments. No data suggesting direct negative effect of eutrofication on orchids were obtained. After the first growing season, no effect of simulated eutrofication on the ratio of fresh mass of tubers in 2007 and 2006 (FM2007/FM2006) was observed. The highest value of this coefficient was 7.79, SD=2.68, n=115. Positive effect of higher nutrient availability on the FM2008/FM2007 was observed after the second growing season, during which the nutrient demand was higher due to higher count of greater plants planted in individual pots. For example, the mean FM2008/FM2007 value of S. lingua treated with 16x diluted solution was 1.21 (SD=0.31, n=23), while for plants treated with undiluted basic solution was the mean 2.20 (SD=0.58, n=23). These results strongly support the opinion that indirect, by competition mediated effect of eutrofication on adult, photosynthezising plants is responsible cause decline of orchid population and the published evidence was discussed with this respect.

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