A study of the mycorrhizal associations of Paulownia taiwaniana

Abstract

The mycorrhizal relationship of Paulownia taiwaniana was investigated on trees from six sites. The species exhibits an endomycorrhizal relationship. Soil spore counts and root colonization levels varied appreciably both between and within sites. Soil from the site with the lowest coefficient of variation for both variables was chosen for a pot trial to investigate the reliance of P. taiwaniana on its fungal symbionts. Growth of P. taiwaniana in the pots was significantly increased by methyl bromide disinfestation of the soil before planting, through the removal of nematodes. This treatment also reduced the mycorrhizal spore count of the soil. Inoculation with a mycorrhizal fungus failed to improve the growth over and above that of the uninoculated plants. Fertilizer increased the growth of the pot plants, but reduced the nutrient level of the tissues expressed as a percentage of the dry mass. It seems unlikely that the perfection of an artificial inoculation technique for P. taiwaniana nurseries could be economically justified.