Impact of plant identity, diversity and composition on diversity, composition and function of nirK-type denitrifying microorganisms in temperate grassland soil

The impact of plant species, the number of plant species (diversity) and the composition of plant species on nirK-type denitrifying microorganisms in soil was studied. NirK encodes the enzyme nitrite reductase which is the key enzyme for dissimilatory nitrate reduction. As a measure for denitrifier function, net and gross dinitrogenoxide (N2O) production rates and denitrifier enzyme activity were determined. Plant identity, diversity and composition influenced the composition of denitrifiers in soil and partially their function. The plant species were Arrhenatherum elatius, Anthoxanthum odoratum, Alopecurus pratensis, Holcus lanatus, Geranium pratense, Plantago lanceolata, Ranunculus acris and Taraxacum officinale. For this study, the following techniques were applied: T-RFLP (terminal restriction fragment length polymorphism), analysis of variance, analysis of covariance, correspondence analysis, canonical correspondence analysis, determination of diversity indices, maximum likelihood