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Andrea Carminati - One of the best experts on this subject based on the ideXlab platform.
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root type matters measurement of Water Uptake by seminal crown and lateral roots in maize
Journal of Experimental Botany, 2018Co-Authors: Felicien Meunier, Mathieu Javaux, Mutez Ali Ahmed, Mohsen Zarebanadkouki, Anders Kaestner, Andrea CarminatiAbstract:The ability of plants to take up Water from the soil depends on both the root architecture and the distribution and evolution of the hydraulic conductivities among root types and along the root length. The mature maize (Zea mays L.) root system is composed of primary, seminal, and crown roots together with their respective laterals. Our understanding of root Water Uptake of maize is largely based on measurements of primary and seminal roots. Crown roots might have a different ability to extract Water from the soil, but their hydraulic function remains unknown. The aim of this study was to measure the location of Water Uptake in mature maize and investigate differences between seminal, crown, and lateral roots. Neutron radiography and injections of deuterated Water were used to visualize the root architecture and Water transport in 5-week-old maize root systems. Water was mainly taken up by crown roots. Seminal roots and their laterals, which were the main location of Water Uptake in younger plants, made a minor contribution to Water Uptake. In contrast to younger seminal roots, crown roots were also able to take up Water from their most distal segments. The greater Uptake of crown roots compared with seminal roots is explained by their higher axial conductivity in the proximal parts and by the fact that they are connected to the shoot above the seminal roots, which favors the propagation of xylem tension along the crown roots. The deeper Water Uptake of crown roots is explained by their shorter and fewer laterals, which decreases the dissipation of Water potential along the roots.
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effect of parameter choice in root Water Uptake models the arrangement of root hydraulic properties within the root architecture affects dynamics and efficiency of root Water Uptake
Hydrology and Earth System Sciences, 2014Co-Authors: Marcel Bechmann, Christoph Schneider, Andrea Carminati, Doris Vetterlein, Sabine Attinger, Anke HildebrandtAbstract:Abstract. Detailed three-dimensional models of root Water Uptake have become increasingly popular for investigating the process of root Water Uptake. However, they suffer from a lack of information on important parameters, particularly on the spatial distribution of root axial and radial conductivities, which vary greatly along a root system. In this paper we explore how the arrangement of those root hydraulic properties and branching within the root system affects modelled Uptake dynamics, xylem Water potential and the efficiency of root Water Uptake. We first apply a simple model to illustrate the mechanisms at the scale of single roots. By using two efficiency indices based on (i) the collar xylem potential ("effort") and (ii) the integral amount of unstressed root Water Uptake ("Water yield"), we show that an optimal root length emerges, depending on the ratio between roots axial and radial conductivity. Young roots with high capacity for radial Uptake are only efficient when they are short. Branching, in combination with mature transport roots, enables soil exploration and substantially increases active young root length at low collar potentials. Second, we investigate how this shapes Uptake dynamics at the plant scale using a comprehensive three-dimensional root Water Uptake model. Plant-scale dynamics, such as the average Uptake depth of entire root systems, were only minimally influenced by the hydraulic parameterization. However, other factors such as hydraulic redistribution, collar potential, internal redistribution patterns and instantaneous Uptake depth depended strongly on the arrangement on the arrangement of root hydraulic properties. Root systems were most efficient when assembled of different root types, allowing for separation of root function in Uptake (numerous short apical young roots) and transport (longer mature roots). Modelling results became similar when this heterogeneity was accounted for to some degree (i.e. if the root systems contained between 40 and 80% of young Uptake roots). The average collar potential was cut to half and unstressed transpiration increased by up to 25% in composed root systems, compared to homogenous ones. Also, the least efficient root system (homogenous young root system) was characterized by excessive bleeding (hydraulic lift), which seemed to be an artifact of the parameterization. We conclude that heterogeneity of root hydraulic properties is a critical component for efficient root systems that needs to be accounted for in complex three-dimensional root Water Uptake models.
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mucilage exudation facilitates root Water Uptake in dry soils
Functional Plant Biology, 2014Co-Authors: Mutez Ali Ahmed, Mohsen Zarebanadkouki, Eva Kroener, Maire Holz, Andrea CarminatiAbstract:As plant roots take up Water and the soil dries, Water depletion is expected to occur in the rhizosphere. However, recent experiments showed that the rhizosphere was wetter than the bulk soil during root Water Uptake. We hypothesise that the increased Water content in the rhizosphere was caused by mucilage exuded by roots. It is probably that the higher Water content in the rhizosphere results in higher hydraulic conductivity of the root–soil interface. In this case, mucilage exudation would favour the Uptake of Water in dry soils. To test this hypothesis, we covered a suction cup, referred to as an artificial root, with mucilage. We placed it in soil with a Water content of 0.03 cm3 cm–3, and used the root pressure probe technique to measure the hydraulic conductivity of the root–soil continuum. The results were compared with measurements with roots not covered with mucilage. The root pressure relaxation curves were fitted with a model of root Water Uptake including rhizosphere dynamics. The results demonstrated that when mucilage is added to the root surface, it keeps the soil near the roots wet and hydraulically well conductive, facilitating the Water flow from dry soils towards the root surface. Mucilage exudation seems to be an optimal plant trait that favours the capture of Water when Water is scarce.
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quantitative imaging of infiltration root growth and root Water Uptake via neutron radiography
Vadose Zone Journal, 2008Co-Authors: Andrea Carminati, Sascha E Oswald, Manoj Menon, Peter Vontobel, Eberhard Lehmann, Rainer SchulinAbstract:Water infiltration into vegetated soils is affected by interactions between soil properties and plant activity. Water Uptake by plant roots depends on the soil hydraulic properties and infiltration rate. In turn, roots are important Water movers and induce nonuniform Water content distributions with consequent impact on the infiltration rate. Our goal was to use neutron radiography to investigate root Water Uptake during rapid infiltration events and subsequent Water redistribution. Neutron radiography is an imaging technique capable of measuring with high spatial and temporal resolution root density, soil structure, and Water distributions in the vicinity of roots. We used time-series neutron radiography to image infiltration events in 0.17- by 0.15- by 0.013-m boxes filled with a sand mixture and that contained either lupine ( Lupinus L.) or maize ( Zea mays L.) plants. We measured four replications at two stages of plant growth. Neutron radiography can detect small variations in Water content with high accuracy and high spatial and temporal resolution. Due to their high Water content, roots were easily visible in the radiograms before infiltration. Following calibration, we quantified the Water content in the sample during and after each infiltration event. Effects of soil heterogeneities such as thin soil layers were visible, as was Water Uptake by roots. We observed lower Water contents along the main root of lupine during the early stage of infiltration, and slower and more diffuse Uptake during the later stages of Water redistribution, when the wetting front had propagated downward and the Water content in the soil decreased. The observed root Water Uptake was not uniform but rather was localized in certain regions. For maize we observed a loss of Water mainly in the upper part of the root system, closer to the stem rather than at root tips.
Ton Van Vliet - One of the best experts on this subject based on the ideXlab platform.
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Water Uptake mechanism in crispy bread crust.
Journal of agricultural and food chemistry, 2008Co-Authors: N. H. Van Nieuwenhuijzen, Rob J. Hamer, MARCELLINUS BERNARDUS JOHANNES MEINDERS, R. Hans Tromp, Ton Van VlietAbstract:Crispness is an important quality characteristic of dry solid food products such as crispy rolls. Its retention is directly related to the kinetics of Water Uptake by the crust. In this study, a method for the evaluation of the Water sorption kinetics in bread crust is proposed. Two different sorption experiments were used: an oscillatory sorption test and a sorption test in which the air relative humidity (RH) was increased stepwise. These two experiments had different time scales, which made it possible to get a better understanding of the mechanisms involved. Results show that the adsorption and desorption dynamics of the oscillatory sorption test could be described by a single exponential in time. The Water Uptake rate (k) was one of the fitting parameters. A maximum in the Water Uptake rate was found for a RH value between 50 and 70%. The rate parameters of the experiment where RH was increased stepwise were around a factor 10 lower tharj those derived from oscillatory sorption experiments. This is an important factor when designing experiments for the determination of Water Uptake rates. In addition, also a parameter describing the time dependence of the rate parameters of the oscillatory sorption experiment was calculated (C), again by fitting a single exponential to the rate parameters. C was in the same range as the rate parameter of the isotherm experiment. This indicates that different (relaxation) processes are acting at the same time in the bread crust during Water Uptake. © 2008 American Chemical Society.
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Water Uptake mechanism in crispy bread crust
Journal of Agricultural and Food Chemistry, 2008Co-Authors: N. H. Van Nieuwenhuijzen, Rob J. Hamer, MARCELLINUS BERNARDUS JOHANNES MEINDERS, R. Hans Tromp, Ton Van VlietAbstract:Crispness is an important quality characteristic of dry solid food products such as crispy rolls. Its retention is directly related to the kinetics of Water Uptake by the crust. In this study, a method for the evaluation of the Water sorption kinetics in bread crust is proposed. Two different sorption experiments were used: an oscillatory sorption test and a sorption test in which the air relative humidity (RH) was increased stepwise. These two experiments had different time scales, which made it possible to get a better understanding of the mechanisms involved. Results show that the adsorption and desorption dynamics of the oscillatory sorption test could be described by a single exponential in time. The Water Uptake rate ( k) was one of the fitting parameters. A maximum in the Water Uptake rate was found for a RH value between 50 and 70%. The rate parameters of the experiment where RH was increased stepwise were around a factor 10 lower than those derived from oscillatory sorption experiments. This is an important factor when designing experiments for the determination of Water Uptake rates. In addition, also a parameter describing the time dependence of the rate parameters of the oscillatory sorption experiment was calculated (C), again by fitting a single exponential to the rate parameters. C was in the same range as the rate parameter of the isotherm experiment. This indicates that different (relaxation) processes are acting at the same time in the bread crust during Water Uptake.
Shiwei Guo - One of the best experts on this subject based on the ideXlab platform.
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high Water Uptake ability was associated with root aerenchyma formation in rice evidence from local ammonium supply under osmotic stress conditions
Plant Physiology and Biochemistry, 2020Co-Authors: Cuimin Gao, Lei Ding, Min Wang, Yupei Chen, Shiwei GuoAbstract:Root Water Uptake is strongly influenced by the morphology and anatomical structure of roots, which are regulated by nitrogen forms and environmental stimuli. To further illustrate the roles of different nitrogen forms on root Water Uptake under osmotic stress, a split-root system was supplied with different nitrogen forms and osmotic stress simulated by adding 10% (w/v) polyethylene glycol (PEG, 6000). The local effects of nitrogen form and osmotic stress on root morphology, anatomical structure, root lignin content, and Water Uptake rate were investigated. Under osmotic stress conditions, ammonium markedly promoted the formation and elongation of the lateral root, whereas a significant decrease in numbers of lateral roots was observed under local nitrate supply. Under nitrate supply in split-root systems, osmotic stress significantly promoted root cell death and more aerenchyma formation, as well as accelerated the lignification of the root. However, osmotic stress had no negative effect on the root anatomical structure under ammonium supply. The root Water Uptake rate was significantly higher in split-root supplied with ammonium than nitrate under osmotic stress conditions. In conclusion, the high Water Uptake ability in local ammonium supply was associated with the more lateral roots development and the lower cell death, aerenchyma formation and lignification under osmotic stress.
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drought induced root aerenchyma formation restricts Water Uptake in rice seedlings supplied with nitrate
Plant and Cell Physiology, 2012Co-Authors: Xiuxia Yang, Binbin Ren, Lei Ding, Cuimin Gao, Qirong Shen, Shiwei GuoAbstract:Previous studies demonstrated that ammonium nutrition results in higher Water Uptake rate than does nitrate nutrition under Water stress, and thus enhances the tolerance of rice plants to Water stress. However, the process by which Water Uptake is related to nitrogen form under Water stress remains unknown. A hydroponic experiment with simulated Water stress induced by polyethylene glycol (PEG6000) was conducted in a greenhouse to study the relationship between root aerenchyma formation and Water Uptake rate, such as xylem sap flow rate and hydraulic conductance, in two different rice cultivars (cv. 'Shanyou 63' hybrid indica and cv. 'Yangdao 6' indica, China). The results showed that root aerenchyma tissue increased in Water-stressed plants of both cultivars fed by nitrate. No significant difference was found in root hydraulic conductivity and/or xylem sap flow rate between the two rice cultivars fed by ammonium regardless of Water status, whereas these parameters decreased significantly in Water-stressed plants fed by nitrate. It was concluded that aerenchyma that formed in the root cortex impeded the radial transport of Water in the root cylinder and decreased Water Uptake in Water-stressed rice plants fed by nitrate. Water transport occurred mainly through Hg-sensitive Water channels in rice roots supplied with ammonium.
Anke Hildebrandt - One of the best experts on this subject based on the ideXlab platform.
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effect of parameter choice in root Water Uptake models the arrangement of root hydraulic properties within the root architecture affects dynamics and efficiency of root Water Uptake
Hydrology and Earth System Sciences, 2014Co-Authors: Marcel Bechmann, Christoph Schneider, Andrea Carminati, Doris Vetterlein, Sabine Attinger, Anke HildebrandtAbstract:Abstract. Detailed three-dimensional models of root Water Uptake have become increasingly popular for investigating the process of root Water Uptake. However, they suffer from a lack of information on important parameters, particularly on the spatial distribution of root axial and radial conductivities, which vary greatly along a root system. In this paper we explore how the arrangement of those root hydraulic properties and branching within the root system affects modelled Uptake dynamics, xylem Water potential and the efficiency of root Water Uptake. We first apply a simple model to illustrate the mechanisms at the scale of single roots. By using two efficiency indices based on (i) the collar xylem potential ("effort") and (ii) the integral amount of unstressed root Water Uptake ("Water yield"), we show that an optimal root length emerges, depending on the ratio between roots axial and radial conductivity. Young roots with high capacity for radial Uptake are only efficient when they are short. Branching, in combination with mature transport roots, enables soil exploration and substantially increases active young root length at low collar potentials. Second, we investigate how this shapes Uptake dynamics at the plant scale using a comprehensive three-dimensional root Water Uptake model. Plant-scale dynamics, such as the average Uptake depth of entire root systems, were only minimally influenced by the hydraulic parameterization. However, other factors such as hydraulic redistribution, collar potential, internal redistribution patterns and instantaneous Uptake depth depended strongly on the arrangement on the arrangement of root hydraulic properties. Root systems were most efficient when assembled of different root types, allowing for separation of root function in Uptake (numerous short apical young roots) and transport (longer mature roots). Modelling results became similar when this heterogeneity was accounted for to some degree (i.e. if the root systems contained between 40 and 80% of young Uptake roots). The average collar potential was cut to half and unstressed transpiration increased by up to 25% in composed root systems, compared to homogenous ones. Also, the least efficient root system (homogenous young root system) was characterized by excessive bleeding (hydraulic lift), which seemed to be an artifact of the parameterization. We conclude that heterogeneity of root hydraulic properties is a critical component for efficient root systems that needs to be accounted for in complex three-dimensional root Water Uptake models.
Mathieu Javaux - One of the best experts on this subject based on the ideXlab platform.
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root type matters measurement of Water Uptake by seminal crown and lateral roots in maize
Journal of Experimental Botany, 2018Co-Authors: Felicien Meunier, Mathieu Javaux, Mutez Ali Ahmed, Mohsen Zarebanadkouki, Anders Kaestner, Andrea CarminatiAbstract:The ability of plants to take up Water from the soil depends on both the root architecture and the distribution and evolution of the hydraulic conductivities among root types and along the root length. The mature maize (Zea mays L.) root system is composed of primary, seminal, and crown roots together with their respective laterals. Our understanding of root Water Uptake of maize is largely based on measurements of primary and seminal roots. Crown roots might have a different ability to extract Water from the soil, but their hydraulic function remains unknown. The aim of this study was to measure the location of Water Uptake in mature maize and investigate differences between seminal, crown, and lateral roots. Neutron radiography and injections of deuterated Water were used to visualize the root architecture and Water transport in 5-week-old maize root systems. Water was mainly taken up by crown roots. Seminal roots and their laterals, which were the main location of Water Uptake in younger plants, made a minor contribution to Water Uptake. In contrast to younger seminal roots, crown roots were also able to take up Water from their most distal segments. The greater Uptake of crown roots compared with seminal roots is explained by their higher axial conductivity in the proximal parts and by the fact that they are connected to the shoot above the seminal roots, which favors the propagation of xylem tension along the crown roots. The deeper Water Uptake of crown roots is explained by their shorter and fewer laterals, which decreases the dissipation of Water potential along the roots.
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plant Water Uptake in drying soils
Plant Physiology, 2014Co-Authors: Guillaume Lobet, Valentin Couvreur, Felicien Meunier, Mathieu Javaux, Xavier DrayeAbstract:Over the last decade, investigations on root Water Uptake have evolved toward a deeper integration of the soil and roots compartment properties, with the goal of improving our understanding of Water acquisition from drying soils. This evolution parallels the increasing attention of agronomists to suboptimal crop production environments. Recent results have led to the description of root system architectures that might contribute to deep-Water extraction or to Water-saving strategies. In addition, the manipulation of root hydraulic properties would provide further opportunities to improve Water Uptake. However, modeling studies highlight the role of soil hydraulics in the control of Water Uptake in drying soil and call for integrative soil-plant system approaches.
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root Water Uptake from three dimensional biophysical processes to macroscopic modeling approaches
Vadose Zone Journal, 2013Co-Authors: Valentin Couvreur, Mathieu Javaux, Jan Vanderborght, Harry VereeckenAbstract:The process description of plant transpiration and soil Water Uptake in macroscopic root Water Uptake models is often based on simplifying assumptions that no longer reflect, or even contradict, the current status of knowledge in plant biology. The sink term in the Richards equation for root Water Uptake generally comprises four terms: (i) a root resistance function, (ii) a soil resistance function, (iii) a stress function, and (iv) a compensation function. Here we propose to use a detailed three-dimensional model, which integrates current knowledge of soil and root Water flow equations, to deduct a one-dimensional effective behavior at the plant scale and to propose improvements for the four functions used in the macroscopic sink term. We show that (i) root hydraulic resistance may be well defined by the root length density but only for homogeneous lateral conductances and no limiting xylem conductance—in other cases a new function depending on the root hydraulic architecture should be used; (ii) soil resistance cannot be neglected, in particular in the rhizosphere where specific processes may occur that alter the soil hydraulic properties and therefore affect Uptake; (iii) stress and compensation are two different processes, which should not be linked explicitly; (iv) there is a need for a clear definition of compensatory root Water Uptake independent of Water stress; (v) stress functions should be defined as a maximal actual transpiration in function of an integrated root–soil interface Water head rather than in terms of local bulk Water heads; and (vi) nonlinearity in the stress function is expected to arise if root hydraulic resistances depend on soil matric head or when it is defined as a function of the bulk soil Water head.
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effect of local soil hydraulic conductivity drop using a three dimensional root Water Uptake model
Vadose Zone Journal, 2008Co-Authors: T Schroder, Mathieu Javaux, Jan Vanderborght, Bernd Korfgen, Harry VereeckenAbstract:The coupling of soil and root Water fluxes at the plant scale is a particularly challenging task. Numerical three-dimensional plant-scale models exist that consider these soil-root interactions. The influence of the hydraulic conductivity drop at the microscopic scale and especially the effect on root Water Uptake is not yet assessed in such models. In this study, an analytical approach describing the hydraulic conductivity drop from the bulk soil to the soil-root interface for a three-dimensional plant-scale model was derived and validated by numerical means. With these tools, quantification of the local hydraulic conductivity drop with time was possible. Furthermore, the effect of the hydraulic conductivity drop on the time occurrence of plant stress was evaluated. Root Water Uptake was assessed, with and without considering the hydraulic conductivity drop around single roots in a three-dimensional plant-scale model in terms of total Water Uptake at the root collar under different soil and root properties. It was shown that the total root Water Uptake was strongly affected, especially under conditions where the radial root hydraulic conductivity, which regulates root Water Uptake, was larger than the soil hydraulic conductivity, which regulates Water flow in the soil. These findings were backed up by numerical validation of the model using mesh refinement. Incorporation of the hydraulic conductivity drop around individual roots in a three-dimensional plant-scale model can solve problems with greater accuracy for larger grid resolutions, and with smaller computational times, than not considering the hydraulic conductivity drop.
