Image analysis is used in numerous studies of root system architecture (RSA). To date, fully automatic procedures have not been good enough to completely replace alternative manual methods. DART (Data Analysis of Root Tracings) is freeware based on human vision to identify roots, particularly across time-series. Each root is described by a series of ordered links encapsulating specific information and is connected to other roots. The population of links constitutes the RSA. DART creates a comprehensive dataset ready for individual or global analyses and this can display root growth sequences along time. We exemplify here individual tomato root growth response to shortfall in solar radiation and we analyse the global distribution of the inter-root branching distances. DART helps in studying RSA and in producing structured and flexible datasets of individual root growth parameters. It is written in JAVA and relies on manual procedures to minimize the risks of errors and biases in datasets.

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To measure the elongation rate of individual roots in soil remains a challenge. A novel method for estimating elongation rates of excavated roots is presented. Morphological markers are identified along the tip of excavated roots, and their distance relative to the apex is measured. These markers correspond to developmental stages which follow known temporal patterns. Hence, their distance relative to the apex reflects root elongation during the period corresponding to their development. The method was tested on maize roots grown in a range of conditions and substrates. It was found that distances from markers to apices were proportional, with some variability, to elongation rates. Remarkably, the linear relationships between these distances were neither affected by substrate, nor by growing conditions. Using several markers allows covering time periods ranging from 0.3 day to 3 days as well as cross validation of estimates. Provided further testing, under a wider range of environmental conditions, is conducted, the concepts presented in this paper may serve to define a new measurement technique

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