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  • Author or Editor: James W. Hendrix x
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Abstract

Isolates of the ectomycorrhizal fungus Pisolithus tinctorius (Pers.) Coker & Couch differed in increasing growth of pin oak seedlings (Quercus palustris Meunchh.) greenhouse-grown in 165 ml tubes containing 1 peat:1 perlite (by volume). At the 4.5 kg/m3 rate of 14N-6P-11.6K Osmocote, a slow release fertilizer, one isolate significantly increased height of seedlings, compared to seedlings not inoculated or inoculated with a second isolate. The 4.5 kg/m3 rate of Osmocote did not suppress mycorrhizae formation by either isolate. At a lower fertilizer rate (1.1 kg/m3 of Osmocote), no differences in height were found among inoculated and uninoculated controls.

Open Access

Abstract

Fresh and stored vegetative mycorrhizal inoculum of Pisolithus tinctorius (Pers.) Coker & Couch were incorporated into steamed media containing slow-release fertilizer. Austrian pine {Pinus nigra Arnold.), Norway spruce (Picea abies (L.) Karst.) and Canadian hemlock (Tsuga canadensis (L.) Carriere) seedlings were grown in 165-ml tubes in a greenhouse for 7 months. Yellow birch (Betula alleghaniensis Britt.) seedlings were grown in 7.6 cm diameter pots. All species formed mycorrhizae but the percent of seedlings which formed mycorrhizae differed among species. Stored inoculum was inferior to fresh inoculum. Differential growth responses to P. tinctorius also occurred among the species. P. tinctorius significantly increased height and stem diameter of Norway spruce only, and reduced the stem diameter of Austrian pine.

Open Access

Abstract

Plants of southern magnolia (Magnolia grandiflora L.) and ‘Bar Harbor’ juniper (Juniperus horizontalis Moench) were grown in a composted hardwood bark: expanded shale medium in 7.6 cm square containers in a greenhouse. All plants received either a low rate (1.1 kg/m3) or the manufacturer's recommended rate (4.5 kg/m3) of 18N-6P-12K slow-release fertilizer, and half the plants received inoculum of Glomus fasciculatus. After 6 months, height of magnolia plants inoculated with G. fasciculatus was nearly twice that of uninoculated plants, and the height difference between the two groups of plants increased with time. In contrast, plants of ‘Bar Harbor’ juniper demonstrated little or no growth response to infection with the mycorrhizal fungus. Fertilization of magnolia plants at the recommended rate as compared with ¼ that rate did not inhibit the degree of mycorrhizal infection of roots. Roots of inoculated ‘Bar Harbor’ juniper plants were heavily infected at both fertilizer rates, but the degree of infection was significantly greater at the lower fertilizer rate.

Open Access

Abstract

Seedlings of pitch pine (Pinus rigida mill.) and Virginia pine (P. virginiana mill.) were grown with and without inoculum of the ectomycorrhizal fungus Pisolithus tinctorius [(Pers.) Coker & Couch] in a sphagnum peatmossperlite medium supplemented with various rates of the slow-release fertilizer (18N–2.5P–10K Osmocote or single rates of 14N–6P–11.6K Osmocote and 19N–3P–8.3K Sierrablen plus ON–19.8P–OK superphosphate) or a soluble 20N–8.6P–16.4K fertilizer treatment. Mycorrhizal development was evaluated after 5 months of growth and then after a 3-month cold storage period. Seedlings heavily mycorrhizal with P. tinctorius and of acceptable planting size were produced with 2.3 to 4.5 kg 18N–2.5P–10K Osmocote/m3 medium. Higher fertilizer rates reduced or eliminated mycorrhizal development and reduced plant growth. Seedlings grown with soluble fertilizer were comparable in size to those produced with slow-release fertilizers, but mycorrhizal development was eliminated. The 3 slow-release fertilizer formulations produced seedlings of comparable size and mycorrhizal development. Superphosphate with or without slow-release or soluble fertilizer did not influence seedling growth or mycorrhizal development. Mycorrhizae continued to develop while plants were in cold storage. The ITW One-Way tube produced seedlings equal in size to those produced in the Leach Pine Cell, but mycorrhizal development appeared to be more sensitive to high fertilizer rates with the ITW tube. Mycorrhizal development did not affect seedling size.

Open Access

Abstract

Tissue-culture-produced nonmycorrhizal strawberry plants (Fragaria x awanassa Duchesne ‘Guardian’) were inoculated with spores of the endogonaceous mycorrhizal fungi Glomus mosseae, G. epigaeum, or G. constrictum. The plants were grown for 14 weeks in the greenhouse in a steamed 1 peat: 1 perlite mixture (v:v) containing a slow release fertilizer, 18-6-12 Osmocote (18N-2.6P-10K), 9-month release rate. Inoculated plants were slightly larger than noninoculated control plants. Roots were colonized more by G. mosseae than by G. epigaeum. No evidence of root colonization by G. constrictum was found, but the fungus sporulated.

Open Access