Growth response of Populus trichocarpa to inoculation by the ectomycorrhizal fungus Laccaria laccata in a pot and a field experiment

摘要

The growth response of Populus trichocarpa cv. Muhle Larsen to inoculation by the ectomycorrhizal (ECM) fungus Laccaria laccata was investigated in a pot and a field experiment on arable soils. Non-sterilized soil from a Cambisol in Wildeshausen (Lower Saxonia, Germany) was taken for the pot experiment. The field experiment was established at a reforestation plantation on Stagnic Gleysols in Leubnitz (Saxonia, Germany). Both arable soils were assumed to be low in indigenous ECM inoculum caused by the lack of host plants. The study was designed to determine (1) the ECM colonization on the poplar clone with or without inoculation in the pot and in the field experiment and (2) the effects of inoculation on plant growth parameters. In the pot experiment, 7% of fine roots of non-inoculated control plants and 18% of inoculated test plants were colonized with ECM fungi after one growing season. In the field experiment, 6% of fine roots were colonized with ECM fungi at the control plot and 20% at the inoculated plot after the first growing season. After the second growing season 50 or 53% were colonized, respectively. The inoculation by L laccata caused significantly increased shoot lengths and leaf potassium concentrations of the poplar clone in the pot and field experiment after the first growing season. In the second growing season, only the leaf potassium concentrations were further increased compared to the non-inoculated control plants. The density of VAM spores in the soil and the leaf nitrogen, magnesium and calcium concentrations were significantly reduced after inoculation. However, after the second growing season there were no longer were significant differences in the ECM colonization and shoot lengths of inoculated or non-inoculated poplar cuttings. The results indicated that inoculation can be successfully used to increase ECM colonization and growth rates of P. trichocarpa on former arable soils in the first growth period. This could increase the resistance of the cuttings to soil-borne pathogens and their competitiveness for nutrients and space against weeds. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 33]