Morphological responses of wheat (Triticum aestivum L.) roots to phosphorus supply in two contrasting soils

• Published in: The Journal of agricultural science Vol. 154; no. 1; pp. 98 - 108
• Main Authors: YUAN, H. M., BLACKWELL, M., MCGRATH, S., GEORGE, T. S., GRANGER, S. H., HAWKINS, J. M. B., DUNHAM, S., SHEN, J. B.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.01.2016
• Subjects: Agricultural ecosystems; agroecosystems; biomass production; breeding; Crops and Soils Research Papers; genotype; Genotypes; Hair; inorganic phosphorus; Phosphorus; root hairs; Roots; soil; Soils; Triticum aestivum; Wheat
• ISSN: 0021-8596; 1469-5146; 1469-5146
• DOI: 10.1017/S0021859615000702

To cope with phosphorus (P) deficiency, plants adapt root morphology to enhance inorganic P (Pi) acquisition from soil by allocating more biomass to roots, but whether the responses can be modified across gradients of P supply is not fully understood. The present study examined changes in root-length density (RLD), root-hair density (RHD) and root-hair length (RHL) of wheat (Triticum aestivum L.) in two contrasting soils, the Rough and Barnfield soils. Wheat plants were grown for 3 weeks in thin-plate rhizotrons in two soils with additions of 0, 10, 25, 50, 100 and 200 mg P/kg soil. Contrary to published literature, as P additions increased it was observed that a concomitant increase in RHL (250 to 1054 µm in the Rough soil and 303–1075 µm in the Barnfield soil) and RHD (57 to 122/mm in the Rough soil and 56–120/mm in the Barnfield soil), while RLD generally decreased (2480–1130 cm/cm3 in the Rough soil and 1716–865 cm/cm3 in the Barnfield soil). The levels of added P that resulted in critical P concentrations in the soils enabling maximum shoot biomass production were 50 mg/kg P in the Rough soil and 100 mg/kg P in the Barnfield soil, and these additions influenced root morphological changes. Under severe P deficiency, P supply increased RHL and RHD, but RLD was decreased. Improvement in lateral root and root-hair responses in wheat at extreme P deficiency may be a worthy target for breeding more sustainable genotypes for future agroecosystems.