Sheared-Root Inocula of Vesicular-Arbuscular Mycorrhizal Fungi

Abstract

For efficient handling, vesicular-arbuscular mycorrhizal fungi should be processed into small and uniform inocula; however, processing can reduce the inoculum density. In this article we describe the preparation and use of sheared-root inocula of Glomus spp. in which inoculum densities were increased during processing. Our objectives were to determine inoculum viability and density after shearing and to ascertain if the sheared inocula could be pelletized or used with a gel carrier. Root samples were harvested from aeroponic cultures, blotted dry, cut into 1-cm lengths, and sheared in a food processor for up to 80 s. After shearing, the inoculum was washed over sieves, and the propagule density in each fraction was determined. Sheared inocula were also encapsulated in carrageenan or used in a gel carrier. Shearing aeroponically produced root inocula reduced particle size. Propagule density increased with decreasing size fraction down to a size of 63 μm, after which propagule density decreased. The weighted-average propagule density of the inoculum was 135,380 propagules g (dry weight) of sheared root material -1 . Sheared roots were encapsulated successfully in carrageenan, and the gel served as an effective carrier. Aeroponic root inoculum was stored dry at 4°C for 23 months without significant reduction in propagule density; however, this material was not appropriate for shearing. Moist roots, useful for shearing, began to lose propagule density after 1 month of storage. Shearing proved to be an excellent method to prepare viable root inocula of small and uniform size, allowing for more efficient and effective use of limited inoculum supplies.

Cryopreservation of entrapped monoxenically produced spores of an arbuscular mycorrhizal fungus

“…Cryopreservation of fungal spores using porous beads was also achieved by Chandler (1994), and ectomycorrhizal fungi entrapped in alginate gels have been shown to retain their infectivity after storage at 4mC for several months (Mauperin et al, 1987). Similar results were reported for AM fungi by Strullu & Plenchette (1991) and Sylvia & Jarstfer (1992). Declerck et al (1996b) further demonstrated that entrapped, monoxenically produced spores of G. versiforme were able to re-infect plants grown in vivo.…”

Monitoring and Control Systems in Agriculture Using Intelligent Sensor Techniques: A Review of the Aeroponic System

“…It provides an excellent chance for plant researchers to deeply study the behavior of plant root under different conditions and without any complications. Until now, many researchers had conducted plant root research and experimental studies root response to drought [64], effects of different oxygen concentrations on plant root development [65,66], root microorganism [67][68][69], arbuscular mycorrhizal fungi production [70], and legume-rhizobia interaction [71]. Furthermore, studies also practiced the technique by growing vegetables, fruits, herbs, and medicinal root-based plant [72][73][74] such as tomato, potato, soybean, maize, lettuce, Anthurium andreanum, and Acacia mangium [15,59,[75][76][77][78][79].…”

Production of Glomus intraradices propagules, an arbuscular mycorrhizal fungus, in an airlift bioreactor

“…Few companies offer AM fungi inocula for agricultural and horticultural uses. Endomycorrhizal inocula are available in the form of spores (propagules formed outside the root) and root pieces containing vesicles (propagules formed inside the root tissue) (Sylvia and Jarstfer, 1992). They are added directly into the surrounding soil of seeds and plantlets.…”