Physiological and morphological adaptations of herbaceous perennial legumes allow differential access to sources of varyingly soluble phosphate |
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| Authors: | Jiayin Pang Jiyun Yang Hans Lambers Mark Tibbett Kadambot HM Siddique Megan H Ryan |
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| Institution: | 1. School of Plant Biology, The University of Western Australia, Perth, Australia;2. The UWA Institute of Agriculture, The University of Western Australia, Perth, Australia;3. The Southern Grassland Ecosystem Research Station, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China;4. School of Earth and Environment, The University of Western Australia, Perth, Australia;5. Department of Environmental Science and Technology, School of Applied Sciences, Cranfield University, Cranfield, UK |
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| Abstract: | The aim of this study was to investigate the capacity of three perennial legume species to access sources of varyingly soluble phosphorus (P) and their associated morphological and physiological adaptations. Two Australian native legumes with pasture potential (Cullen australasicum and Kennedia prostrata) and Medicago sativa cv. SARDI 10 were grown in sand under two P levels (6 and 40 µg P g?1) supplied as Ca(H2PO4)2·H2O (Ca‐P, highly soluble, used in many fertilizers) or as one of three sparingly soluble forms: Ca10(OH)2(PO4)6 (apatite‐P, found in relatively young soils; major constituent of rock phosphate), C6H6O24P6Na12 (inositol‐P, the most common form of organic P in soil) and FePO4 (Fe‐P, a poorly‐available inorganic source of P). All species grew well with soluble P. When 6 µg P g?1 was supplied as sparingly soluble P, plant dry weight (DW) and P uptake were very low for C. australasicum and M. sativa (0.1–0.4 g DW) with the exception of M. sativa supplied with apatite‐P (1.5 g). In contrast, K. prostrata grew well with inositol‐P (1.0 g) and Fe‐P (0.7 g), and even better with apatite‐P (1.7 g), similar to that with Ca‐P (1.9 g). Phosphorus uptake at 6 µg P g?1 was highly correlated with total root length, total rhizosphere carboxylate content and total rhizosphere acid phosphatase (EC 3.1.3.2) activity. These findings provide strong indications that there are opportunities to utilize local Australian legumes in low P pasture systems to access sparingly soluble soil P and increase perennial legume productivity, diversity and sustainability. |
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