Non-inoculated Control Seedlings Research Articles

Allelopathic effects of interrupted fern on northern red oak seedlings: Amelioration bySuillus luteus L.: Fr.

The allelopathic effects of interrupted fern frond leachates on ectomycorrhizal (inoculated) and nonmycorrhizal (noninoculated) northern red oak (Quercus rubra L.) seedlings were investigated. Container-grown northern red oak was inoculated with vegetative mycelium ofSuillus luteus L. Fr. following acorn germination. Noninoculated control seedlings were also maintained. Seedlings were grown in a glasshouse under full sunlight or shaded (25% of full sunlight) conditions. Leachate or deionized water solutions were applied to seedlings eleven times over a 91-day period to simulate a rainfall induced transfer of allelopathic chemicals from fern fronds to the soil. Fern frond leachates significantly reduced seedling survival, however, inoculated seedlings showed less mortality. Chromium concentrations of pooled lateral root or leaf tissue were comparatively higher in tissues exhibiting greater mortality. Root biomass was reduced by fern fern frond leachate applications. Seedling biomass was not significantly affected by fungal inoculation. Our results confirm previous documentation of the allelopathic potential of ferns, and suggest that ectomycorrhizal fungi may ameliorate allelopathic effects of ferns on northern red oak seedling survival and growth.

Field performance of Pinus caribaea var. Hondurensis seedlings with specific ectomycorrhizae and fertilizer after three years on a savanna site in Liberia

Seedlings of Pinus caribaea var. hondurensis were grown in containers for 4 months in a bush nursery in Gbarnga, Liberia. Vegetative inocula of Pisolithus tinctorius (Pt), Thelephora terrestris (Tt), and soil inoculum, called Monrovia mixture (MM), collected from under 16-year-old trees of the same species, were used to form specific ectomycorrhizae on the seedlings. Seedlings in these three treatments received the same fertility in the nursery as seedlings in a noninoculated control treatment; in a fifth nursery treatment noninoculated control seedlings received 25% more fertilizer. Seedlings inoculated with Pt, Tt, and MM had ectomycorrhizae on 61, 18, and 6% of their short roots, respectively. These inoculated seedlings were significantly smaller, with lower top/root ratios, and contained less foliar N than seedlings in either control treatment. A trace of ectomycorrhizae was detected microscopically on seedlings in both control treatments. It was concluded that this contamination came from the introduced Tt which formed abundant fruit bodies in the nursery. Seedlings were outplanted on a prepared savanna site near Gbarnga; half of the seedlings in each treatment were fertilized. Seedlings were measured at the end of each 7.5-month rainy season and each 4.5-month dry season for 3 years. At the end of the first rainy season, seedlings inoculated with Tt in the nursery and the two controls had an average of 49% Tt ectomycorrhizae, regardless of field fertilization. Over 2000 Tt fruit bodies were found during each rainy season in each of these plots. Seedlings in the Pt and MM treatments had 82 and 86% ectomycorrhizae, of which only 2–11% were formed by Tt. The fungi were reisolated from their respective ectomycorrhizae. Rhizosphere soil from seedlings with Pt ectomycorrhizae contained more total N than soil from seedlings in other treatments. These samples, however, did not differ in N 2-fixation rate (acetylene reduction technique) from other soil samples containing less total N collected at the beginning of the third dry season. After the first rainy season, seedlings with Pt ectomycorrhizae with and without field fertilization had significantly more N and other elements in needles than most other treatments. These differences were much less after the third rainy season. After 3 years, seedling survival (96.0-83.6%) was not seriously affected by treatment. Seedlings with Pt ectomycorrhizae in fertilized plots had significantly greater seedling and plot volumes than those in other treatments. Only seedlings with Pt ectomycorrhizae responded to field fertilization. Seedlings with MM ectomycorrhizae had greater volumes than seedlings with Tt ectomycorrhizae or seedlings in either control treatment. Seedlings intentionally inoculated with Tt were not significantly different in any field measurement from those in the two control treatments contaminated with Tt. Seedlings with Pt and MM ectomycorrhizae grew as much or more during the short dry season than seedlings of other treatments grew during the longer rainy season. Physical properties of stem tissue sampled at the end of the third rainy season did not vary by treatment. Bark averaged 35.5% of stem tissue. Moisture content of wood was 192.5% and specific gravity of wood and bark was 0.293. Fruit bodies of Alpova pachyphloeus were found in 4- and 5-year old pine plantations and those of Thelephora sp. were found on pine seedlings left in the nursery prior to fungal introductions. Since all of these seedlings had been inoculated with MM in the Gbarnga nursery, these fungi coild be components of the MM inoculum or they could be indigenous on native trees in the Gbarnga area. Pt fruit bodies were observed 2 km downwind from the study site in young plantations of Eucalyptus grandis and E. camaldulensis. Apparently basidiospores of Pt were windblown from the study site to these plantations. It was concluded that differences in seedling growth caused by specific ectomycorrhizal and field fertilization treatments were attributed to differences in amounts of ectomycorrhizae formed during the growing season and in efficacy of specific ectomycorrhizae in nutrient and water absorption.

The use of ectomycorrhizal conifer seedlings in the revegetation of a high-elevation mine site

Three conifer species, Pinnscontorta Dougl., Pinusflexilis James, and Piceaengelmannii Parry, were inoculated with the ectomycorrhizal fungi Pisolithustinctorius (Pers.) Coker & Couch, Suillusgranulatus (L. ex Fr.) Kuntze, and Cenococcumgeophilum Fr. These, plus noninoculated control seedlings, were grown in a greenhouse for 8 months to assess mycorrhizal formation and seedling response. For all conifer species, top height, diameter, and seedling total dry weight were greater in the S. granulatus and control ("wild" fungus) treatments as compared with P. tinctorius and C. geophilum.In the 2nd year of the study, greenhouse container-grown conifers with ectomycorrhizae formed by the above three fungi and an unknown fungus were planted under four fertilizer treatments on a high-elevation (3200 m) molybdenum tailing pond covered with deep mine waste rock.After 4 years in the field, height growth of the seedlings (all tree species combined) inoculated with S. granulatus were greater than seedlings inoculated with P. tinctorius, C. geophilum, or control ("wild" fungus). Through four growing seasons, a sewage sludge and wood-chip treatment resulted in greater height growth than the three treatments of combined inorganic N and P, P alone, and no fertilization. The combined survival for all species and all treatments was 58% after four growing seasons.

Container- and nursery-grown black oak seedlings inoculated with Pisolithustinctorius: growth and ectomycorrhizal development following outplanting on an Ozark clear-cut

Containerized and bare-rooted black oak (Quercusvelutina Lam.) seedlings were inoculated with vegetative mycelial inoculum of Pisolithustinctorius and were grown in a greenhouse and a southern Missouri nursery, respectively. Following outplanting on a typical Missouri Ozark reforestation site, field data revealed that Pisolithus ectomycorrhizae increased survival and growth of the container-grown seedlings. Container-grown seedlings inoculated with Pisolithus exhibited significantly greater shoot and root growth than noninoculated control seedlings or inoculated bare-rooted seedlings. A complimentary relationship between root initiation, leaf area development, and shoot growth suggests a better growth potential of Pisolithus-inoculated container-grown seedlings than of noninoculated container-grown or inoculated or noninoculated bare-rooted seedlings. One year after outplanting, data revealed that Pisolithus is declining on the inoculated containerized and bare-rooted seedlings, but greater amounts of Pisolithus ectomycorrhizae are persisting on the container-grown plants.

Container- and nursery-grown black oak seedlings inoculated with Pisolithustinctorius: growth and ectomycorrhizal development during seedling production period

Vegetative mycelial inoculum of Pisolithustinctorius was used to inoculate black oak (Quercusvelutina Lam.) seedlings grown in containers in a greenhouse and in a fumigated soil in a southern Missouri nursery. Evaluations of seedlings in the greenhouse and the nursery at the end of the first growing season revealed that Pisolithus formed ectomycorrhizae on approximately 40% of the lateral roots. In the nursery, seedling dry weight, shoot length, root collar diameter, and leaf area were significantly greater for inoculated seedlings than for noninoculated control seedlings. For container-grown seedlings, total dry weight, root dry weight, and leaf surface area were significantly increased by inoculation with Pisolithus. These results demonstrate that Pisolithus can be artifically introduced into fumigated nursery soil and sterile growth medium of containers and form ectomycorrhizae on black oak seedlings under greenhouse and nursery conditions.