Comparison of soil microorganism abundance and diversity in stands of European aspen (Populus tremula L.) and hybrid aspen (Populus tremuloides Michx. x P. tremula L.)/Mulla mikroorganismide arvukuse ja mitmekesisuse vordlus hariliku haava (Populus tremula L.) ning hubriidhaava (Populus tremuloides Michx. x P. tremula L.) puistutes

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From: Estonian Journal of Ecology(Vol. 61, Issue 4)
Publisher: Estonian Academy Publishers
Document Type: Report
Length: 6,871 words
Lexile Measure: 1620L

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Abstract :

The use of short rotation forest tree species is increasing worldwide. The hybrid aspen (Populus tremuloides Michx. x P. tremula L.) is one of the suitable tree species under the climatic conditions of the Baltic region. The cultivation of these trees on former agricultural soils differs from agricultural practices with reduced soil tillage and is characterized by increased demand of nutrients, which in long term can cause changes in the soil microbial populations. The aim of our investigation was to compare soil microbial populations in hybrid aspen and European aspen (P. tremula L.) stands in four sampling plots with aspen age ranging from 10 to 46 years. The abundance and diversity of soil microbial populations were estimated by enumeration of microorganisms (plate counts on three microbiological media) and by molecular methods (PCR, ARDRA, molecular identification of fungal isolates). Results showed that during long cultivation periods hybrid aspens reduced the number of culturable bacteria. The number of culturable filamentous fungi was statistically significantly increased only in one sampling plot in soil samples from hybrid aspen clones at a depth of 16-30 cm and only on one microbiological cultivation medium. The same was detected also with molecular methods in the case of fungal diversity estimated by Shannon-Weaver diversity indices in this sampling plot. None of the other characteristi[C.sub.s] of soil microbial populations, such as the number of yeasts and maltose utilizing bacteria on MEA, the number of yeasts and filamentous fungi on RBA, the total amount of soil DNA, fungal and bacterial diversity estimated by molecular biology methods, and species composition of filamentous fungi, was significantly affected by hybrid aspen. The identified filamentous fungi represented the following genera: Acremonium, Exophiala, Geomyces, Gibellulopsis, Gibberella, Hypocrea/Trichoderma, Leptosphaeria, Metarhizium, Mortierella, Nectria, Paecilomyces, Penicillium, Trichosporon, and others. The main conclusion was that cultivation of hybrid aspen as a short rotation forest tree in the Baltic region would not significantly affect the abundance and diversity of saprophytic soil microorganisms. Key words: hybrid aspen, soil microorganisms, microbial diversity, soil filamentous fungi. Luhikese raieringiga majandatavaid puuliike kasutatakse maailma metsanduses uha enam. Balti regiooni kliimatingimustes on hubriidhaab (Populus tremuloides Michx. x P. tremula L.) osutunud selleks otstarbeks sobilikuks. Luhikese raieringiga puuistandike kasvatamine endistel pollumuldadel erineb tavapollumajandusest vahenenud maaharimise ja suurenenud toitainenoudluse poolest, mis pikas perspektiivis voib pohjustada muutusi mulla mikroobikooslustes. Kaesoleva uurimuse eesmargiks oli vorrelda mulla mikroobikooslusi hubriidhaava ja hariliku haava (P. tremula L.) puistutes neljal proovialal, kus haabade vanus jai vahemikku 10 kuni 46 aastat. Mulla mikroobikoosluste arvukuse ja mitmekesisuse hindamiseks kasutati nende loendamist (plaadikulv kolmel erineval tardsootmel) ning molekulaarseid meetodeid (PCR, ARDRA, seene isolaatide molekulaarne identifitseerimine). Tulemused naitasid, et hubriidhaava pikaaegse kasvatamise tagajarjel vaheneb kultiveeritavate bakterite arvukus. Kultiveeritavate niitjate seente arvukus oli statistiliselt usaldusvaarselt suurenenud vaid uhe hubriidhaava katseala mullas sugavusel 16-30 cm ja ainult uhel mikrobioloogilisel sootmel. Seda kinnitas mainitud katsealal ka molekulaarsete meetoditega maaratud seente mitmekesisus, mida hinnati Shannon-Weaveri mitmekesisuse indeksiga. Teisi mulla mikroobikoosluse tunnuseid (parmi ja maltoosi tarvitavate bakterite arvukus virdeagaril, parmide ning niitjate seente arvukus Rose-Bengali tardsootmel, kogu mullast eraldatud DNA, molekulaarbioloogiliste meetoditega leitud seente ja bakterite mitmekesisus ning niitjate seente liigiline koosseis) ei olnud hubriidhaabade kasv usaldusvaarselt mojutanud. Maaratud niitjad seened esindasid jargmisi perekondi: Acremonium, Exophiala, Geomyces, Gibellulopsis, Gibberella, Hypocrea/Trichoderma, Leptosphaeria, Metarhizium, Mortierella, Nectria, Paecilomyces, Penicillium, Trichosporon ja teised. Peamise jareldusena leiti, et hubriidhaava kasvatamine luhikese raieringiga majandatava lehtpuuna Balti regioonis ei mojuta margatavalt saprofuutsete mulla mikroorganismide ohtrust ja mitmekesisust.

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Gale Document Number: GALE|A316796592