Effects of X-ray dose on rhizosphere studies using X-ray computed tomography

Zappala, Susan; Helliwell, Jonathan R.; Tracy, Saoirse; Mairhofer, Stefan; Sturrock, Craig; Pridmore, Tony; Bennett, Malcolm J.; Mooney, Sacha J.

Abstract

X-ray Computed Tomography (CT) is a non-destructive imaging technique originally designed for diagnostic medicine, which was adopted for rhizosphere and soil science applications in the early 1980s. X-ray CT enables researchers to simultaneously visualise and quantify the heterogeneous soil matrix of mineral grains, organic matter, air-filled pores and water-filled pores. Additionally, X-ray CT allows visualisation of plant roots in situ without the need for traditional invasive methods such as root washing. However, one routinely unreported aspect of X-ray CT is the potential effect of X-ray dose on the soil-borne microorganisms and plants in rhizosphere investigations. Here we aimed to i) highlight the need for more consistent reporting of X-ray CT parameters for dose to sample, ii) to provide an overview of previously reported impacts of X-rays on soil microorganisms and plant roots and iii) present new data investigating the response of plant roots and microbial communities to X-ray exposure. Fewer than 5% of the 126 publications included in the literature review contained sufficient information to calculate dose and only 2.4% of the publications explicitly state an estimate of dose received by each sample. We conducted a study involving rice roots growing in soil, observing no significant difference between the numbers of root tips, root volume and total root length in scanned versus unscanned samples. In parallel, a soil microbe experiment scanning samples over a total of 24 weeks observed no significant difference between the scanned and unscanned microbial biomass values. We conclude from the literature review and our own experiments that X-ray CT does not impact plant growth or soil microbial populations when employing a low level of dose (

Citation

Zappala, S., Helliwell, J. R., Tracy, S., Mairhofer, S., Sturrock, C., Pridmore, T., …Mooney, S. J. (2013). Effects of X-ray dose on rhizosphere studies using X-ray computed tomography. PLoS ONE, 8(6), Article e67250. https://doi.org/10.1371/journal.pone.0067250

• Journal Article Type: Article
• Publication Date: Jun 26, 2013
• Deposit Date: Apr 1, 2014
• Publicly Available Date: Apr 1, 2014
• Journal: PLoS ONE
• Electronic ISSN: 1932-6203
• Publisher: Public Library of Science
• Peer Reviewed: Peer Reviewed
• Volume: 8
• Issue: 6
• Article Number: e67250
• DOI: https://doi.org/10.1371/journal.pone.0067250
• Public URL: https://nottingham-repository.worktribe.com/output/715482
• Publisher URL: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0067250