科研之友
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摘要
The effects on soil microorganisms of a three-year cultivation programme using mineral and manure fertilization on three perennial medicinal plant species, lemon balm (Melissa officinalis L), sage (Salvia officinalis L), and lavender (Lavandula angustifolia Mill.), were studied. Root endophyte colonization, namely arbuscular mycorrhizal fungi (AMF), dark septate endophytes (DSE) and Olpidium spp., as well as AMF species richness and abundance in the soil, soil respiration, microbial biomass, and the activity and functional richness of culturable bacterial communities were assessed. In the mineral fertilization treatment (MRL), phosphorus and potassium fertilizers were incorporated at the beginning of the experiment, while nitrogen fertilizer was applied throughout its course. In the manure fertilization treatment (MAN), animal manure was applied once four years prior to soil and plant sampling. The soil under MRL was characterized by a higher pH and P, N and Ca contents. AMF colonization of sage under MAN was lower in comparison to MRL; however, no significant differences were found in the case of lemon balm and lavender. The results of the Plantago lanceolata L laboratory bioassay in respect of the infectivity potential of the AMF present in the soils tested were in accordance with the trends obtained from mycorrhizal colonization assessments of the medicinal plant species. DSE and Olpidium spp. were also observed in the roots subjected to analysis; however, they were not abundant. In the case of sage, DSE were more frequent in MAN, while no significant differences were found in lemon balm and lavender. In contrast, Olpidium spp. were more abundant in the sage and lavender from MRL Moreover, the lemon balm roots were devoid of these endophytes. The spores of 15 AMF species from 10 genera were isolated from trap cultures established from the soils collected in the field. The species richness found in MRL was higher than that in MAN. Moreover, four AMF species were detected exclusively in the trap cultures established from the soils collected from under lemon balm, two were exclusive to sage and one to lavender. The soil basal respiration was significantly affected by the plant species, but not by the fertilization systems and this parameter was lowest under lemon balm and highest under lavender. The microbial biomass differed significantly between management types only for lemon balm and was lower in MAN than in MRL Bacterial activity was affected neither by plant species nor by fertilization type. Bacterial functional richness was significantly influenced only by the fertilization type in interaction with the plant species and was higher in MAN than in MRL for sage. Our results suggest that moderate application of mineral fertilizers does not suppress, and sometimes enhances. AMF and other soil microorganisms. Moreover, the effects of the fertilization type on soil microbial properties depend on the plant species being cultivated.
- 出版日期2012-8
