The `Ammophila Problem' Revisited: A Role for Mycorrhizal Fungi

Abstract

1 A glasshouse study was conducted to determine the effects of three variables (sand burial, arbuscular mycorrhizal (AM) fungi and endoparasitic root nematodes) and their interactions on the growth of Ammophila breviligulata Fern. seedlings. We tested the hypotheses that burial allows A. breviligulata to escape from plant-parasitic nematodes and that inoculation with AM fungi is another factor capable of ameliorating the detrimental effects of nematodes to the plant. 2 Seedlings were grown in y-irradiated, sterile sand and treated in a factorial manner with 5 cm of sand burial, i'hizosphere inoculation with AM fungi and rhizosphere inoculation with plant parasitic nematodes. Both AM fungi and nematodes originated from field populations of A. breviligulata. 3 Burial stimulated the foliar growth rate of plants in all combinations except when plants had been infected with nematodes prior to burial. The root dry weight was significantly reduced when nematode infected plants were buried. AM fungi improved the foliar growth rate and root dry weight of buried plants infected with nematodes. We therefore rejected the hypothesis that burial allows escape from plant-parasitic nematodes. 4 AM fungi are capable of reducing plant susceptibility to plant-parasitic nematodes and must be considered when assessing the influence of plant-parasites on the vigour of natural A. breviligulata populations.