The Cultivation of Arabidopsis for Experimental Research Using Commercially Available Peat-Based and Peat-Free Growing Media

RESEARCH ARTICLE The Cultivation of Arabidopsis for Experimental Research Using Commercially Available Peat-Based and Peat-Free Growing Media Tiffany Drake1, Mia Keating1, Rebecca Summers1, Aline Yochikawa1¤, Tom Pitman1, Antony N. Dodd1,2* a11111 1 School of Biological Sciences, University of Bristol, Bristol Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, United Kingdom, 2 Cabot Institute, University of Bristol, Bristol BS8 1UJ, United Kingdom ¤ Current address: Universidade Estadual de Campinas, Cidade Universitária "Zeferino Vaz", Barão Geraldo, Campinas, São Paulo, Brazil * OPEN ACCESS Citation: Drake T, Keating M, Summers R, Yochikawa A, Pitman T, Dodd AN (2016) The Cultivation of Arabidopsis for Experimental Research Using Commercially Available Peat-Based and PeatFree Growing Media. PLoS ONE 11(4): e0153625. doi:10.1371/journal.pone.0153625 Editor: Hiroshi Ezura, University of Tsukuba, JAPAN Received: November 4, 2015 Accepted: April 2, 2016 Published: April 18, 2016 Copyright: © 2016 Drake et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All data files are available from the University of Bristol data repository (DOI:10.5523/bris.50mnf5ey5ep31txaj7krtpuq7). Funding: This work was supported by the UK Biotechnology and Biological Sciences Research Council (www.bbsrc.ac.uk, grant BB/I005811/2), The Royal Society (royalsociety.org; University Research Fellowship, grant UF120033), The University of Bristol's BSc and MSci (Biological Sciences) programmes, no grant number (www.bristol.ac.uk/ biology/), National Council of Technological and Scientific Development (CNPq) Brazil (www.cnpq.br) Science without Borders Program (studentship Abstract Experimental research involving Arabidopsis thaliana often involves the quantification of phenotypic traits during cultivation on compost or other growing media. Many commerciallyavailable growing media contain peat, but peat extraction is not sustainable due to its very slow rate of formation. Moreover, peat extraction reduces peatland biodiversity and releases stored carbon and methane into the atmosphere. Here, we compared the experimental performance of Arabidopsis on peat-based and several types of commercially-available peat-free growing media (variously formed from coir, composted bark, wood-fibre, and domestic compost), to provide guidance for reducing peat use in plant sciences research with Arabidopsis. Arabidopsis biomass accumulation and seed yield were reduced by cultivation on several types of peat-free growing media. Arabidopsis performed extremely poorly on coir alone, presumably because this medium was completely nitrate-free. Some peatfree growing media were more susceptible to fungal contamination. We found that autoclaving of control (peat-based) growing media had no effect upon any physiological parameters that we examined, compared with non-autoclaved control growing media, under our experimental conditions. Overall, we conclude that Arabidopsis performs best when cultivated on peat-based growing media because seed yield was almost always reduced when peat-free media were used. This may be because standard laboratory protocols and growth conditions for Arabidopsis are optimized for peat-based media. However, during the vegetative growth phase several phenotypic traits were comparable between plants cultivated on peatbased and some peat-free media, suggesting that under certain circumstances peat-free media can be suitable for phenotypic analysis of Arabidopsis. PLOS ONE | DOI:10.1371/journal.pone.0153625 April 18, 2016 1 / 16 Peat-Free Cultivation of Arabidopsis 249210/2012-6), University of Bristol Santander Scholarship, no grant number (www.bristol.ac.uk) and the Kyoto University (Joint Usage/Research Program of the Center for Ecological Research). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. Introduction Peat extraction can be unsustainable and cause environmental damage, but some peat-free growing media are anecdotally poor for the cultivation of Arabidopsis thaliana (Arabidopsis) for experimental purposes. Plant sciences research involving Arabidopsis requires reproducible plant cultivation; for example during developmental or physiological analysis. Here, we compared systematically several experimentally-relevant phenotypic traits of wild type Arabidopsis that was cultivated using a selection of peat-free growing media. Peat is an organic material formed from the accumulation of dead plant tissue where decomposer activity is very low. Peat often occurs in anaerobic, waterlogged environments [1]. Peat extraction can be damaging to habitats, unsustainable and may contribute to anthropogenic climate change. Peatlands represent a major habitat, comprising over 400 million hectares of land on Earth [2]. However, most natural bog in Great Britain has been destroyed for a variety of reasons, such as extraction of horticultural peat and electricity generation [3]. For example, 6,949 ha of peatland (48%) in UK Special Areas of Conservation are considered to be degraded [4]. It was estimated that in the United Kingdom alone, 2.69 x 106 m3 of peat is extracted annually for commercial horticultural and domestic (gardening) purposes, 99% of which is used to produce growing media [4]. The quantity of peat that is used for plant sciences research involving Arabidopsis is not known. Peat extraction has impacted peatland biodiversity, including population declines in the large heath butterfly [5] and reduced genetic variation in native plants [6]. Additionally, archaeological and paleontological sites have been destroyed by peat extraction [7, 8]. Estimates of the UK peat stores vary from 1.5 million hectares to 5 million hectares [9]. The rate of peat accumulation depends on environmental conditions, but is estimated to be slow (around 100 cm every 1000–2000 years [2, 7]). Mechanised milling can remove the entire peat body, making recovery especially slow [3, 10]. The European Commission does not regard peat as a renewable resource because it can be extracted faster than it is formed [4]. European Union legislation previously required 90% of growing media sold by 2010 to be peat-free and the UK government aims to end the use of peat in horticulture by 2030 [11]. Peatlands are highly concentrated organic carbon stores because they are formed from plant material. The average rate of carbon sequestration by peat is reported to be 17.2 g m-2 yr-1 [12] with peatlands of Great Britain estimated to contain 5.1 billion tonnes of carbon [13]. Therefore, peat formation and extraction can impact the atmospheric concentration (...truncated)