Plant Water-Uptake Effects on Salt Distribution Near the Root-Soil Interface.

The paradigm today is that when salinity increases beyond a certain threshold it will result in reduced crop yield at a fixed rate. Thus, there is a great importance of predicting salinization and its impact on crops. Current models do not consider the impact of environmental conditions on salt tolerance in plants, even though these conditions are affecting plants water uptake and thus salts accumulation around the roots. Better parametrization of a model can help to improve predicting the real effects of salinity on crop growth and yield. The aim of this research is to study Na⁺ distribution around roots at different scales by investigating different non-invasive methods, and study how this distribution is being affected by transpiration rate and plant water uptake. Results from tomato plants growing on Rhizoslides (capillary paper growth system), show that Na⁺ concentration is higher at the root interface, compared with the bulk. Also, Na⁺ accumulation around the roots decreased under low transpiration rate. Additionally, Rhizoslides enable to study roots’ growth rate and architecture under different salinity levels. To observe the correlation of root system architectures and Na⁺ distribution in three dimensions, we used Magnetic resonance imaging (MRI). MRI provides fine resolution of Na⁺ accumulation around a single root, without disturbing the root system. With time, Na⁺ was accumulating only where roots were found and later on around specific roots. These data are being used for model calibration, which is expected to predict root water uptake in saline soils for different climatic conditions and different soil water availabilities. Rhizoslides allows investigating root systems of larger plants but is limited by the medium (paper) and dimension (2D). The MRI is able to create a 3D image of Na⁺ accumulation in soil in a microscopic scale.