Chalmers Conferences, 9th European Conference on Mathematical and Theoretical Biology

Image-based plant phosphate uptake modelling: a case study for root hairs using synchrotron X-ray CT imaging
Sam D. Keyes, Keith R. Daly, Neil Gostling, Alan Marchant, Ian Sinclair, Tiina Roose

Last modified: 2014-06-09


Root-hairs are single-cell extensions to the plant root epidermis, and are known to be important for plant acquisition of the highly immobile nutrients such as phosphate (P) and potassium (K).  Experiments using radio-labelled phosphate have suggested that root hairs can be responsible for over 50% of P uptake [1].  With poor P bio-availability being limiting for crop growth in many agricultural contexts, there is significant motivation to uncover key root hair traits for optimal acquisition efficiency in different soils.  Due to the small length-scales of relevant features (~1μm), and the associated difficulties with direct sensing of nutrient dynamics, it is numerical modelling that has become the leading tool for understanding these processes at the rhizosphere scale[2-4].

We have developed a suite of synchrotron-based 3D imaging and image-based simulation techniques which have allowed parameterisation of numerical models with undisturbed, soil-grown root hair morphology for the first time.  A novel plant growth protocol has facilitated the application of in vivo synchrotron X-ray computed tomography (SRXCT) at resolutions in the range 0.6-1.5 μm, revealing the interactions between undisturbed root hairs and rhizosphere soil.  The computational resources of the Iridis 4 supercomputer at the University of Southampton have then been used to solve a mechanistic, image-based P-uptake model using finite-element computational methods [5].

This combination of approaches in the X-ray imaging, image-processing and computational-modelling domains represents a powerful toolbox for advancing our understanding of how different root hair traits may either enhance or limit uptake of poorly mobile nutrients in the rhizosphere.  Moreover, these combined imaging and modelling approaches present opportunities to advance fundamental understanding in many other spheres of rhizosphere research.



[1] Gahoonia, T. S. & Nielsen, N. E. Direct evidence on participation of root hairs in phosphorus uptake from soil, Plant and Soil 198, 147–152, (1998).

[2] Roose, T. & Fowler, A. C. A mathematical model for water and nutrient uptake by plant root systems, Journal of theoretical biology 228, 173–184, (2004).

[3] Darrah, P. R., Jones, D. L., Kirk, G. J. D. & Roose, T. Modelling the rhizosphere: a review of methods for “upscaling” to the whole-plant scale, European Journal of Soil Science 57, 13–25, (2006).

[4] Zygalakis, K. C., Kirk, G. J. D., Jones, D. L., T, W. & Roose, T. A dual porosity model for the uptake of nutrients by root hairs, New Phytologist 192, 676–688, (2011).

[5] Keyes, S. D. et al. High resolution synchrotron imaging of wheat root hairs growing in soil and image based modelling of phosphate uptake, New Phytologist 198, 1023–1029, (2013).