Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8846670 | Applied Soil Ecology | 2018 | 10 Pages |
Abstract
Annual pasture legumes with a superior ability to acquire soil phosphorus (P) and a low external critical P requirement could reduce the need for P fertiliser. Roots of pasture legumes grown in field soil will commonly be colonised by arbuscular mycorrhizal fungi (AMF). However, recent research suggests a second community of arbuscule-forming root-colonising fungi may be present: fine root endophytes (FRE). AMF are known to enhance P acquisition by plants under certain conditions, whereas very little is known about FRE and their impact on plant P status. We, therefore, grew plants at seven levels of P supply to determine and compare the external critical P requirements of two species of Ornithopus and two cultivars of Trifolium subterraneum when colonised predominantly by FRE (FRE-dominant treatment) or both FRE and AMF (mixed treatment). As expected from previous studies, the Ornithopus species had a lower critical P requirement than the T. subterraneum cultivars. However, for the Ornithopus species only, the FRE-dominant community had a significantly lower external critical P requirement (24-31â¯mgâ¯Pâ¯kgâ1 soil) than the mixed community (50-58â¯mgâ¯Pâ¯kgâ1 soil). Moreover, at low-P supply (â¤15â¯mg applied Pâ¯kgâ1 soil), Ornithopus species in the FRE-dominant treatment had longer specific root length, smaller average root diameter, 45-128% greater total root length, and lower shoot and root P concentration than in the mixed treatment. We concluded that comparisons among experiments of root morphological traits and external critical P requirements can be affected by the presence of different communities of arbuscule-forming root-colonising fungi and that these effects may vary among plant species.
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Authors
Robert P. Jeffery, Richard J. Simpson, Hans Lambers, Suzanne Orchard, Daniel R. Kidd, Rebecca E. Haling, Megan H. Ryan,