Overcoming Kalmia induced allelopathic growth inhibition of black spruce by mycorrhizal inoculation: disagreement between laboratory and field experiments.
Mallik, Azim1, Zeng, Ren-Sen, Walker, Gregg, 1 Lakehead University, Thunder Bay, Ontario, Canada
ABSTRACT- Tree seedlings inoculated with ectomycorrhizal fungi have been found to improve survival and growth in ecologically inhospitable sites. We tested if Kalmia induced allelopathic growth inhibition in black spruce can be overcome by ecomycorrhizal inoculation of black spruce seedlings. Our laboratory and greenhouse experiments showed that out of 51 ecotmycorrhizae four were not only able to tolerate the toxicity of Kalmia leachate but exhibited better root and shoot growth in the presence of Kalmia leachate as well as in iving Kalmia compared to the control. In laboratory experiments we found that Paxilus involutus was able to degrade Kalmia phenolic compounds and use them as their carbon source to have increased growth of mycellial biomass and colony diameter. However, when the black spruce seedlings pre-inoculated with P. involutus were outplanted in Kalmia sites they did not show significant growth enhancement compared to the uninoculated control seedlings. Functional differences in different stains of ectomycorrhizae and rhizosphere ecology of Kalmia under field conditions are discussed.
Key words: Kalmia, Allelopathy, Ectomycorrhiza, Disturbance
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