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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

Yun-Jeong Lee*, Sang-Min Lee, and Seung-Hwan Kim

The elemental distribution (P, Ca, K, Mg) within inter- and intracellular structure of arbuscular mycorrhizal (AM) cucumber root was determined using energy dispersive X-ray spectroscopy (EDAX). Cucumber (Cucumis sativus cv. Chinesische Schlange) was grown as a test plant using compartmentalized pots with separate zones for hyphal growth and was inoculated or not with the AM fungus, Glomus mosseae (BEG 107). EDAX studies revealed that P in intercellular structures including fungal cells in cucumber root colonized with AM was mainly localized in both polyphosphate granules in arbuscular vacuole and arbuscular cytoplasm. Ca in AM root was mostly localized in cortex cell wall, interfacial apoplast between root and fungus, arbuscular cytoplasm and poly phosphate granules. Mg was distributed homogenously in most cell compartments within AM root while K was localized mainly in cell wall of stele. Higher contents of Ca and Mg were detected in polyphosphate granules whereas lower content of K was detectable. These results indicate that polyphosphate granules could play a role as a complex forming site with metal cations especially with divalent cations like Ca and Mg. In addition, it could give a possibility of regulation function of polyphosphate granules on element transfer from fungus to host plant root. Furthermore, the distribution of element within cortex cytoplasm, interfacial apoplast between plant root and fungus and arbuscular cytoplasm might give a clue on the element transfer mechanism between symbionts.

Open access

Youn Young Hur, Su Jin Kim, Jeong Ho Roh, Kyo Sun Park, Hae Keun Yun, Jong Chul Nam, Sung Min Jung, Sang Uk Koh, Dong Jun Im, Dong Hoon Lee, Seo June Park, and Kyong Ho Chung