Quantifying total phosphorus accumulation below-ground by canola and lupin plants using 33P-labelling
- 635 Downloads
Background and aims
Measures of phosphorus (P) in roots recovered from soil underestimate total P accumulation below-ground by crop species since they do not account for P in unrecovered (e.g., fine) root materials. 33P-labelling of plant root systems may allow more accurate estimation of below-ground P input by plants.
Using a stem wick-feeding technique 33P-labelled phosphoric acid was fed in situ to canola (Brassica napus) and lupin (Lupinus angustifolius) grown in sand or loam soils in sealed pots.
Recovery of 33P was 93 % in the plant-soil system and 7 % was sorbed to the wick. Significantly more 33P was allocated below-ground than to shoots for both species with 59–90 % of 33P measured in recovered roots plus bulk and rhizosphere soil. 33P in recovered roots was higher in canola than lupin regardless of soil type. The proportion of 33P detected in soil was greater for lupin than canola grown in sand and loam (37 and 73 % lupin, 20 and 23 % canola, respectively). Estimated total below-ground P accumulation by both species was at least twice that of recovered root P and was a greater proportion of total plant P for lupin than canola.
Labelling roots using 33P via stem feeding can empower quantitative estimates of total below-ground plant P and root dry matter accumulation which can improve our understanding of P distribution in soil-plant systems.
KeywordsRoot-derived P Total below-ground P Unrecovered root dry weight Shoot P:total root P
Total below-ground phosphorus
Recovered root phosphorus
Root-derived phosphorus in bulk soil
Root-derived phosphorus in rhizosphere soil
Dry weight of unrecovered roots
The senior author thanks the Grains Research and Development Corporation (GRDC) for providing top up funding (GRS10026) to support this research and the University of Adelaide for an Australian Postgraduate Scholarship. We also thank CSIRO for use of their radioisotope laboratory facilities and access to a field site for soil collection. This work contributes to outputs in GRDC project UA00119.
- Armstrong E, Pate J, Tennant D (1994) The field pea crop in south western Australia - patterns of water use and root growth in genotypes of contrasting morphology and growth habit. Funct Plant Biol 21:517–532Google Scholar
- Bundy LG, Tunney H, Halvorson AD (2005) Agronomic aspects of phosphorus management. In Phosphorus: Agriculture and the Environment. Eds. J T Sims and A N Sharpley. pp 685–727. American Society of Agronomy, Crop Science Society of America, and Soil Science Society of AmericaGoogle Scholar
- Frossard E, Achat D, Bernasconi S, Bünemann E, Fardeau J-C, Jansa J, Morel C, Rabeharisoa L, Randriamanantsoa L, Sinaj S, Tamburini F, Oberson A (2011) The use of tracers to investigate phosphate cycling in soil–plant systems. In: Bünemann E, Oberson A, Frossard E (eds) Phosphorus in action. Springer, Berlin, pp 59–91CrossRefGoogle Scholar
- Gregory PJ (2008) Development and growth of root systems. In: Peter GJ (ed) Plant roots: growth, activity and interactions with the soil. Blackwell Publishing, OxfordGoogle Scholar
- Hoad SP, Russell G, Lucas ME, Bingham IJ (2001) The management of wheat, barley, and oat root systems. In Advances in Agronomy. pp 193–246. Academic PressGoogle Scholar
- Hocking PJ (2001) Organic acids exuded from roots in phosphorus uptake and aluminum tolerance of plants in acid soils. In Advances in Agronomy. pp 63–97. Academic PressGoogle Scholar
- Martin J, Cunningham R (1973) Factors controlling the release of phosphorus from decomposing wheat roots. Aust J Biol Sci 26:715–728Google Scholar
- McNeill A (2001) Stable isotope techniques using enriched 15N and 13C for studies of soil organic matter accumulation and decomposition in agricultural systems. In: Unkovich M, Pate J, McNeill A, Gibbs DJ (eds) Stable isotope techniques in the study of biological processes and functioning of ecosystems. Springer, Netherlands, pp 195–218CrossRefGoogle Scholar
- Merrill SD, Tanaka DL, Hanson JD (2005) Comparison of fixed-wall and pressurized-wall minirhizotrons for fine root growth measurements in eight crop species USDA-ARS is an equal opportunity/affirmative action employer, and all agency services are available without discrimination. Agron J 97:1367–1373CrossRefGoogle Scholar
- Norton A, Kirkegaard J, Angus J, TP (2013) Canola in Rotations 7. The Regional Institute, http://www.regional.org.au/au/gcirc/canola/p-06.htm
- Rayment G, Higginson FR (1992) Australian laboratory handbook of soil and water chemical methods. Inkata Press Pty Ltd, MelborneGoogle Scholar
- Rennie D, Halstead E (1965) A 32P injection method for quantitative estimation of the distribution and extent of cereal grain roots. Proc. Isotopes and radiations in soil-plant nutrition studies. FAO/IAEA, Ankara, p 489Google Scholar
- Vijayalakshmi K, Dakshinamurti C (1975) Quantitative estimation of root weight using 32P plant injection technique. J Nucl Agric Biol 4:98–100Google Scholar
- Zarcinas BA, Cartwright B (1983) Analysis of soil and plant material by inductively coupled plasma-optical emission spectrometry. CSIRO, MelbourneGoogle Scholar