Above‐ and below‐ground responses of Calamagrostis purpurea to UV‐B radiation and elevated CO 2 under phosphorus limitation

• Published in: Physiologia Plantarum
• Main Authors: Bussell, Jenny S., Gwynn‐Jones, Dylan, Griffith, Gareth W., Scullion, John
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2012
• Subjects: Cell Biology; Plant Science; Genetics; General Medicine; Physiology; Arctic
• Online Access: http://dx.doi.org/10.1111/j.1399-3054.2012.01595.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1399-3054.2012.01595.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1399-3054.2012.01595.x

UV‐B radiation and elevated CO 2 may impact rhizosphere processes through altered below‐ground plant resource allocation and root exudation, changes that may have implications for nutrient acquisition. As nutrients limit plant growth in many habitats, their supply may dictate plant response under elevated CO 2 . This study investigated UV‐B exposure and elevated CO 2 effects, including interactions, on plant growth, tissue chemistry and rooting responses relating to P acquisition. The sub‐arctic grass Calamagrostis purpurea was subjected to UV‐B (0 or 3.04 kJ m −2 day −1 ) and CO 2 (ambient 380 or 650 ppmv) treatments in a factorial glasshouse experiment, with sparingly soluble P (0 or 0.152 mg P per plant as FePO 4 ) a further factor. It was hypothesized that UV‐B exposure and elevated CO 2 would change plant resource allocation, with CO 2 mitigating adverse responses to UV‐B exposure and aiding P uptake. Plant biomass and morphology, tissue composition and rhizosphere leachate properties were measured. UV‐B directly affected chemical composition of shoots and interacted with CO 2 to give a greater root biomass. Elevated CO 2 altered the composition of both shoots and roots and increased shoot biomass and secondary root length, while leachate pH decreased. Below‐ground responses to CO 2 did not affect P acquisition although P limitation progressively reduced leachate pH and increased secondary root length. Although direct plant growth, foliar composition and below‐ground nutrient acquisition responses were dominated by CO 2 treatments, UV‐B modified these CO 2 responses significantly. These interactions have implications for plant responses to future atmospheric conditions.