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An Axenic Plant Culture System for Optimal Growth in Long-Term Studies: Design and MaintenanceThe symbiotic co-evolution of plants and microbes leads to difficulties in understanding which of the two components is responsible for a given environmental response. Plant-microbe studies greatly benefit from the ability to grow plants in axenic (sterile) culture. Several studies have used axenic plant culture systems, but experimental procedures are often poorly documented, the plant growth environment is not optimal, and axenic conditions are not rigorously verified. We developed a unique axenic system using inert components that promotes plant health and can be kept sterile for at least 70 d. Crested wheatgrass (Agropyron cristatum cv. DII) plants were grown in sand within flow-through glass columns that were positively pressured with filtered air. Plant health was optimized by regulating temperature, light level, CO2 concentration, humidity, and nutrients. The design incorporates several novel aspects, such as pretreatment of the sand with Fe, graduated sand layers to optimize the air-water balance of the root zone, and modification of a laminar flow hood to serve as a plant growth chamber. Adaptations of several sterile techniques were necessary for maintenance of axenic conditions. Axenic conditions were verified by plating and staining leachates as well as rhizoplane stain. This system was designed to study nutrient and water stress effects on root exudates, but is useful for assessing a broad range of plant-microbe-environment interactions. Based on total organic C analysis, 74% of exudates was recovered in the leachate, 6% was recovered in the bulk sand, and 17% was recovered in the rhizosphere sand. Carbon in the leachate after 70 d reached 255 micro-g/d. Fumaric, malic, malonic, oxalic, and succinic acids were measured as components of the root exudates.
Document ID
20060026143
Acquisition Source
Johnson Space Center
Document Type
Reprint (Version printed in journal)
Authors
Henry, Amelia
(Utah State Univ. Logan, UT, United States)
Doucette, William
(Utah State Univ. Logan, UT, United States)
Norton, Jeanette
(Utah State Univ. Logan, UT, United States)
Jones, Scott
(Utah State Univ. Logan, UT, United States)
Chard, Julie
(Utah State Univ. Logan, UT, United States)
Bugbee, Bruce
(Utah State Univ. Logan, UT, United States)
Date Acquired
August 23, 2013
Publication Date
March 1, 2006
Publication Information
Publication: Jounral of Environmental Quality: Technical Reports: Plant and Environment Interactions
Volume: 35
Subject Category
Exobiology
Report/Patent Number
Paper-7552
Funding Number(s)
CONTRACT_GRANT: NAG9-1311
Distribution Limits
Public
Copyright
Other

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