Modelling the impact of heterogeneous rootzone water distribution on the regulation of transpiration by hormone transport and/or hydraulic pressures
- 532 Downloads
A simulation model to demonstrate that soil water potential can regulate transpiration, by influencing leaf water potential and/or inducing root production of chemical signals that are transported to the leaves.
Signalling impacts on the relationship between soil water potential and transpiration were simulated by coupling a 3D model for water flow in soil, into and through roots (Javaux et al. 2008) with a model for xylem transport of chemicals (produced as a function of local root water potential). Stomatal conductance was regulated by simulated leaf water potential (H) and/or foliar chemical signal concentrations (C; H + C). Split-root experiments were simulated by varying transpiration demands and irrigation placement.
While regulation of stomatal conductance by chemical transport was unstable and oscillatory, simulated transpiration over time and root water uptake from the two soil compartments were similar for both H and H + C regulation. Increased stomatal sensitivity more strongly decreased transpiration, and decreased threshold root water potential (below which a chemical signal is produced) delayed transpiration reduction.
Although simulations with H + C regulation qualitatively reproduced transpiration of plants exposed to partial rootzone drying (PRD), long-term effects seemed negligible. Moreover, most transpiration responses to PRD could be explained by hydraulic signalling alone.
KeywordsSoil-root modelling R-SWMS Hormonal signalling Stomatal conductance Partial rootzone drying
This work is a contribution of the Transregio Collaborative Research Centre 32. Patterns in Soil-Vegetation-Atmosphere Systems: Monitoring, Modelling and Data Assimilation, which is funded by the German research association, DFG. ICD thanks the EU project SIRRIMED (FP7- KBBE-2009-3-245159) for continued support of work on PRD.
- Bravdo BA (2005) Physiological mechanisms involved in the production of non-hydraulic root signals by partial rootzone drying - A review. In: LE Williams (ed) Proceedings of the Seventh International Symposium on Grapevine Physiology and Biotechnology. International Society Horticultural Science, Leuven 1Google Scholar
- Dodd IC, Theobald JC, Richer SK, Davies WJ (2009) Partial phenotypic reversion of ABA-deficient flacca tomato (Solanum lycopersicum) scions by a wild-type rootstock: normalising shoot ethylene relations promotes leaf area but does not diminish whole plant transpiration rate. J Exp Bot 60:4029–4039PubMedCrossRefPubMedCentralGoogle Scholar
- Doussan C, Vercambre G, Pagès L (1998) Modelling of the hydraulic architecture of root systems: an integrated approach to water absorption—distribution of axial and radial conductances in maize. Ann Bot 81(2): 225–232Google Scholar
- Dzikiti S, Verreynne JS, Stuckens J, Strever A, Verstraeten WW, Swennen R, Coppin P (2010) Determining the water status of satsuma mandarin trees citrus unshiu marcovitch using spectral indices and by combining hyperspectral and physiological data. Agric For Meteorol 150:369–379. doi:10.1016/j.agrformet.2009.12.005 CrossRefGoogle Scholar
- Feddes RA, Kowalik PJ, Zaradny H (1978) Simulation of field water use and crop yield. Pudoc Wageningen, The NetherlandsGoogle Scholar
- Franks PJ, Drake PL, Froend RH (2007) Anisohydric but isohydrodynamic: seasonally constant plant water potential gradient explained by a stomatal control mechanism incorporating variable plant hydraulic conductance. Plant Cell Environ 30:19–30. doi:10.1111/j.1365-3040.01600.x PubMedCrossRefGoogle Scholar
- Javaux M, Couvreur V, Vanderborght J, Vereecken H (2013) Root Water Uptake: From Three-Dimensional Biophysical Processes to Macroscopic Modeling Approaches. Vadose Zone Journal 12. doi:10.2136/vzj2013.02.0042
- Martin-Vertedor AI, Dodd IC (2011) Root-to-shoot signalling when soil moisture is heterogeneous: increasing the proportion of root biomass in drying soil inhibits leaf growth and increases leaf abscisic acid concentration. Plant Cell Environ 34:1164–1175. doi:10.1111/j.1365-3040.2011.02315.x PubMedCrossRefGoogle Scholar
- Puértolas J, Alcobendas R, Alarcón JJ, Dodd IC (2013) Long-distance abscisic acid signalling under different vertical soil moisture gradients depends on bulk root water potential and average soil water content in the root zone. Plant Cell Environ 36:1465–1475. doi:10.1111/pce.12076 PubMedCrossRefGoogle Scholar
- Romero P, Dodd IC, Martinez-Cutillas A (2012) Contrasting physiological effects of partial root zone drying in field-grown grapevine (Vitis vinifera L. cv. Monastrell) according to total soil water availability. J Exp Bot 63:4071–4083. doi:10.1093/jxb/ers088 PubMedCrossRefPubMedCentralGoogle Scholar
- Schroder N, Javaux M, Vanderborght J, Steffen B, Vereecken H (2012) Effect of Root Water and Solute Uptake on Apparent Soil Dispersivity: A Simulation Study. Vadose Zone Journal 11. doi:10.2136/vzj2012.0009
- Schurr U, Gollan T, Schulze ED (1992) Stomatal response to drying soil in relation to changes in the xylem sap composition of helianthus-annuus.2. Stomatal sensitivity to abscisic-acid imported from the xylem sap. Plant Cell Environ 15:561–567. doi:10.1111/j.1365-3040.1992.tb01489.x CrossRefGoogle Scholar
- Taiz L, Zeiger E (2006) Plant physiology/Lincoln Taiz; Eduardo Zeiger. Sinauer, Sunderland, MassGoogle Scholar
- Wilson JB (1988) A review of evidence on the control of shoot: root ratio, in relation to models. Ann Bot 61:433–449Google Scholar
- Yin X, van Laar HH (2005) Crop systems dynamics : an ecophysiological simulation model for genotype-by-environment interactions/Xinyou Yin; H. H. van Laar. Academic Publishers, WageningenGoogle Scholar