THE GROWTH, NUTRIENT ABSORPTION, AND MOISTURE STATUS OF SELECTED WOODY SPECIES IN COAL MINE SPOIL IN RESPONSE TO AN INDUCED INFECTION BY THE ECTOMYCORRHIZAL FUNGUS PISOLITHUS TINCTORIUS.

摘要

The growth, nutrient absorption, and internal moisture status of selected woody species in coal mine spoil in response to an induced infection by the ectomycorrhizal fungus Pisolithus tinctorius was studied. Nursery grown loblolly and Virginia pine seedlings infected with Pisolithus and control seedlings were outplanted on a coal mine spoil in Tennessee which had been previously hydroseeded with a mixture of herbaceous ground cover species. Granular fertilizer was applied by broadcasting to one-half of the seedlings of each ectomycorrhizal treatment at the rate of 112 kg/ha NPK. After three years, the survival and growth of loblolly pine infected with Pisolithus was superior to that of the control seedlings, and chemical analyses of foliar samples revealed that the seedlings with Pisolithus ectomycorrhizae had a higher foliar concentration of NO(,3) and a lower concentration of Zn than the control seedlings. The survival, growth, and nutrient absorption of Virginia pine was not significantly affected by the infection with Pisolithus after two years, but both loblolly and Virginia pine seedlings with Pisolithus ectomycorrhizae exhibited an enhanced ability to absorb water during periods of high moisture stress, as determined by the pressure chamber technique. Fertilization substantially reduced the survival of the seedlings of both species.;Sweet birch and European alder were grown under high, intermediate, and low fertility regimes in sand culture containing a mycelial inoculum of Pisolithus tinctorius for five months and then transplanted to coal mine spoil containing an identical Pisolithus inoculum. Control seedlings of each species were similarly grown except that no inoculum was incorporated into the potting media. The nutrient treatments initiated in the sand culture were continued throughout the study. Examinations of the roots of the sweet birch seedlings revealed that high fertility significantly reduced the development of Pisolithus ectomycorrhizae, but Pisolithus formed abundant ectomycorrhizae on the roots of sweet birch grown under the intermediate and low fertility regimes and these seedlings were significantly larger than comparable control seedlings. Chemica analyses of foliar samples revealed that sweet birch seedlings with Pisolithus ectomycorrhizae had a significantly higher foliar concentration of total N and a lower concentration of Mg and Al than the conrol seedlings No ectomycorrhizal fungi were found to have infected the roots of the European alder seedlings of any of the ectomycorrhizal-nutrient treatment combinations.