Architectural characterization of the Soybean Root System

Author(s)

Dioger Alexandre Teruel

• Document type: Doctoral Thesis
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 1999-10-29
• Advisor: Durval Dourado Neto

Abstract

Root systems are difficult to observe, quantify, and interpret, being those the reasons why the scientific knowledge about roots is so poor. Different techniques for the study of roots in soil are discussed and used. The structural complexity of root systems make root architecture impossible to be properly analyzed and understood by classical statistics, being the simulation modeling an attractive approach (Wullschleger et al., 1994; Lynch, 1995), even more if associated with architectural analysis based on topological indexes (Fitter, 1985; 1987 and Fitter et al., 1991). A mechanistic model of root growth and architecture is formulated, and topological indexes and their significance as indicators of different strategies of adaptation to an edaphic environment are discussed. There is a wide variation in the shape and architecture of root systems between individuals of a same plant species. Root architecture is a determining factor in the adaptive success of a species in a given environment, since changes in the architectural configuration allows the plant to achieve an optimum soil exploration and exploitation. Root systems can alter their architecture so that they can achieve a balance between accelerated soil exploration (extension growth) and maximum exploitation efficiency (profuse branching). The plant species studied in this project is soybean, since most of the structural and functional investigations of root systems have been done on a few species, with emphasis on the monocotyledons, being the herbaceous dicotyledons still almost untouched (McCully, 1995). Accordingly, the experimental data and the images simulated by the model show changes in root architecture in response to the soil nutrient (phosphorus) content (AU)