Simulating Root Density Dynamics and Nitrogen Uptake – Can a Simple Approach be Sufficient?

The modeling of root growth in many plant–soil models is simple and with few possibilities to adapt simulated root proliferation and depth distribution to that actually found with different crop species. Here we propose a root model, developed to describe root growth, root density and nitrogen uptake. The model focuses on annual crops, and attempts to model root growth of different crop species and row crops and its significance for nitrogen uptake from different parts of the soil volume

Phosphate availability regulates root system architecture in Arabidopsis

Plant root systems are highly plastic in their development and can adapt their architecture in response to the prevailing environmental conditions. One important parameter is the availability of phosphate, which is highly immobile in soil such that the arrangement of roots within the soil will profoundly affect the ability of the plant to acquire this essential nutrient. Consistent with this, the availability of phosphate was found to have a marked effect on the root system architecture of Arabidopsis. Low phosphate availability favored lateral root growth over primary root growth, through increased lateral root density and length, and reduced primary root growth mediated by reduced cell elongation. The ability of the root system to respond to phosphate availability was found to be independent of sucrose supply and auxin signaling. In contrast, shoot phosphate status was found to influence the root system architecture response to phosphate availability

Modelling root distribution and nitrogen uptake

Plant soil and atmosphere models are commonly used to predict crop yield and environmental consequence. Such models often include complex modelling modules for water movement, soil organic matter turnover and, above ground plant growth. However, the root modelling in these models are often very simple, partly due to a limited access to experimental data. We present a two-dimensional model for root growth and proliferation. The model focuses on annual crops, and attempt to model root growth of the crops and its significance for N uptake from different parts of the soil volume

Hormonal regulation of wheat growth during hydroponic culture

Hormonal control of root growth has been explored as one means to alleviate the crowding of plant root systems experienced in prototype hydroponic biomass production chambers being developed by the CELSS Breadboard Project. Four plant hormones, or their chemical analogs, which have been reported to selectively inhibit root growth, were tested by adding them to the nutrient solutions on day 10 of a 25 day growth test using spring wheat in hydroponic cultures. Growth and morphological changes is both shoot and root systems were evaluated. In no case was it possible to inhibit root growth without a comparable inhibition of shoot growth. It was concluded that this approach is unlikely to prove useful for wheat

Simulating Root Density Dynamics and Nitrogen Uptake -Field Trials and Root Model Approach in Denmark

Plant soil and atmosphere models are commonly used to predict crop yield and associated environmental consequences. Such models often include complex modelling of water movement, soil organic matter turnover and above ground plant growth. However, the root modelling in these models is often very simple, partly due to a limited access to experimental data. Here we propose a root model developed to describe root growth, root density and nitrogen uptake. The model focuses on annual crops, and attempts to model root growth of different crop species and row crops and its significance for nitrogen uptake from different parts of the soil volume

Root growth and signalling: the role of calcium channels

Roots acquire calcium not only as a macronutrient but also to serve as a second messenger in signalling and a component of exocytosis for growth. Plasma membrane channels are sufficient to deliver calcium from the apoplast to the cytosol to enable its participation in nutrition, adaptation and development. The identity and regulatory mechanisms of these channels are central to our understanding of how calcium manages to “do it all”. By studying Arabidopsis roots, it’s been possible to discover plasma membrane channels involved in growth and signalling, allied to the finding that plants utilise the most damaging reactive oxygen species, the hydroxyl radical, constructively. As an overarching regulator, roots utilise extracellular purine nucleotides in a calcium-based signalling system that differs substantially from that of animals.Universidad de Málaga. Campus Internacional Andalucía Tec

Root production is determined by radiation flux in a temperate grassland community

Accurate knowledge of the response of root turnover to a changing climate is needed to predict growth and produce carbon cycle models. A soil warming system and shading were used to vary soil temperature and received radiation independently in a temperate grassland dominated by Holcus lanatus L. Minirhizotrons allowed root growth and turnover to be examined non-destructively. In two short-term (8 week) experiments, root responses to temperature were seasonally distinct. Root number increased when heating was applied during spring, but root death increased during autumnal heating. An experiment lasting 12 months demonstrated that any positive response to temperature was short-lived and that over a full growing season, soil warming led to a reduction in root number and mass due to increased root death during autumn and winter. Root respiration was also insensitive to soil temperature over much of the year. In contrast, root growth was strongly affected by incident radiation. Root biomass, length, birth rate, number and turnover were all reduced by shading. Photosynthesis in H. lanatus exhibited some acclimation to shading, but assimilation rates at growth irradiance were still lower in shaded plants. The negative effects of shading and soil warming on roots were additive. Comparison of root data with environmental measurements demonstrated a number of positive relationships with photosynthetically active radiation, but not with soil temperature. This was true both across the entire data set and within a shade treatment. These results demonstrate that root growth is unlikely to be directly affected by increased soil temperatures as a result of global warming, at least in temperate areas, and that predictions of net primary productivity should not be based on a positive root growth response to temperature