@article{MoradiCarminatiVetterleinetal.2011,
  author    = {Moradi, Ahmad B. and Carminati, Andrea and Vetterlein, Doris and Vontobel, Peter and Lehmann, Eberhard and Weller, Ulrich and Hopmans, Jan W. and Vogel, Hans-J{\"o}rg and Oswald, Sascha},
  title     = {Three-dimensional visualization and quantification of water content in the rhizosphere},
  series = {New phytologist : international journal of plant science},
  volume    = {192},
  journal   = {New phytologist : international journal of plant science},
  number    = {3},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0028-646X},
  doi       = {10.1111/j.1469-8137.2011.03826.x},
  pages     = {653 -- 663},
  year      = {2011},
  abstract  = {Despite the importance of rhizosphere properties for water flow from soil to roots, there is limited quantitative information on the distribution of water in the rhizosphere of plants. Here, we used neutron tomography to quantify and visualize the water content in the rhizosphere of the plant species chickpea (Cicer arietinum), white lupin (Lupinus albus), and maize (Zea mays) 12 d after planting. We clearly observed increasing soil water contents (h) towards the root surface for all three plant species, as opposed to the usual assumption of decreasing water content. This was true for tap roots and lateral roots of both upper and lower parts of the root system. Furthermore, water gradients around the lower part of the roots were smaller and extended further into bulk soil compared with the upper part, where the gradients in water content were steeper. Incorporating the hydraulic conductivity and water retention parameters of the rhizosphere into our model, we could simulate the gradual changes of h towards the root surface, in agreement with the observations. The modelling result suggests that roots in their rhizosphere may modify the hydraulic properties of soil in a way that improves uptake under dry conditions.},
  language  = {en}
}
@article{CarminatiSchneiderMoradietal.2011,
  author    = {Carminati, Andrea and Schneider, Christoph L. and Moradi, Ahmad B. and Zarebanadkouki, Mohsen and Vetterlein, Doris and Vogel, Hans-J{\"o}rg and Hildebrandt, Anke and Weller, Ulrich and Sch{\"u}ler, Lennart and Oswald, Sascha},
  title     = {How the rhizosphere may favor water availability to roots},
  series = {Vadose zone journal},
  volume    = {10},
  journal   = {Vadose zone journal},
  number    = {3},
  publisher = {Soil Science Society of America},
  address   = {Madison},
  issn      = {1539-1663},
  doi       = {10.2136/vzj2010.0113},
  pages     = {988 -- 998},
  year      = {2011},
  abstract  = {Recent studies have shown that rhizosphere hydraulic properties may differ from those of the bulk soil. Specifically, mucilage at the root-soil interface may increase the rhizosphere water holding capacity and hydraulic conductivity during drying. The goal of this study was to point out the implications of such altered rhizosphere hydraulic properties for soil-plant water relations. We addressed this problem through modeling based on a steady-rate approach. We calculated the water flow toward a single root assuming that the rhizosphere and bulk soil were two concentric cylinders having different hydraulic properties. Based on our previous experimental results, we assumed that the rhizosphere had higher water holding capacity and unsaturated conductivity than the bulk soil. The results showed that the water potential gradients in the rhizosphere were much smaller than in the bulk soil. The consequence is that the rhizosphere attenuated and delayed the drop in water potential in the vicinity of the root surface when the soil dried. This led to increased water availability to plants, as well as to higher effective conductivity under unsaturated conditions. The reasons were two: (i) thanks to the high unsaturated conductivity of the rhizosphere, the radius of water uptake was extended from the root to the rhizosphere surface; and (ii) thanks to the high soil water capacity of the rhizosphere, the water depletion in the bulk soil was compensated by water depletion in the rhizosphere. We conclude that under the assumed conditions, the rhizosphere works as an optimal hydraulic conductor and as a reservoir of water that can be taken up when water in the bulk soil becomes limiting.},
  language  = {en}
}