Search Results

You are looking at 1 - 2 of 2 items for

  • Author or Editor: Eckhard George x
  • Refine by Access: All x
Clear All Modify Search
Free access

Yun-Jeong Lee and Eckhard George

A nutrient film technique (NFT) culture system was developed to allow nursery production of arbuscular mycorrhizal horticultural crops. This would benefit horticultural production and allow for uncomplicated production of mycorrhizal hyphae. Roots of lettuce (Lactuca sativa var. capitata) plants were highly colonized by the arbuscular mycorrhizal fungus, Glomus mosseae (BEG 107) after 4 weeks in the NFT system, following an initial phase of five weeks in inoculated in Perlite substrate. In the NFT system, a thin layer of glass beads was used to provide solid support for plant and fungus growth and nutrient solution was supplied intermittently (15 min, six times per day). A modified nutrient solution (80 μm P) was used and was replaced with fresh solution every 3 days. A significantly higher dry weight was found for the mycorrhizal versus the nonmycorrhizal lettuce plants in Perlite during the precolonization period. The root colonization rate was also high at rates up to 80 μm P supply. On the NFT system, growth differences between mycorrhizal and nonmycorrhizal plants were less than in Perlite. However, root colonization rate was not reduced during the NFT culture period. In this system, high amounts of fungal biomass were produced. This would allow the determination of metal and other nutrient concentrations in fungal hyphae. Furthermore, we found large amounts of external fungal hyphae surrounding the root surface. As much as 130 mg fungal biomass were collected per culture plate (three plants). Therefore, we suggest that this modified NFT culture system would be suitable for fungal biomass production on a large scale with a view to additional aeration by intermittent nutrient supply, optimum P supply, and a use of glass beads as support materials. Furthermore, bulk inoculum composition with a mixture of spores, colonized roots, and hyphae grown in soilless media by the modified NFT system might be a useful way to mass-produce mycorrhizal crops and inoculum for commercial horticultural purposes.

Free access

Henrike Perner, Dietmar Schwarz, and Eckhard George

Organic horticultural production systems often are characterized by the use of beneficial soil microorganisms because the application of soluble inorganic P or N fertilizers is not endorsed. Due to the limited supply of soluble nutrients in organic production systems, nutrient deficiency may limit plant growth and yield. The sole use of peat for pot-based cultures is also discouraged in organic production systems. Therefore, we have studied viable alternatives for highly soluble fertilizers and pure peat substrates using leek [Allium ampeloprasum L. var. Porrum] as a test plant. Plants were grown on peat-based substrates with different rates of compost additions, and with and without inoculation with arbuscular mycorrhizal (AM) fungi. Inoculation with a commercial AM fungus inoculum resulted in colonization rates of up to 70% of total root length, whereas not inoculated plants remained free of root colonization. Mycorrhizal fungus colonization increased shoot Zn and K concentrations, but did not significantly affect shoot dry matter or shoot N and P concentrations. In contrast, compost addition increased plant growth, and also increased P and K concentrations in plants. We conclude that plants with high rates of mycorrhizal colonization can be obtained on peat-based substrates, but that under these conditions plants may not consistently benefit in growth from the mycorrhizal symbiosis. In contrast, additions of compost are a possible means to improve the substrate quality in organic horticultural production.