An architectural model of the sunflower root system using a Markovian approach

IZQUIERDO, N.G.; THEVENON, M.A.; SAN MARTINO, S.; DOSIO, G.A.A.; AGUIRREZÁBAL, L.A.N.

Toulouse, Francia

Conferencia; 15è Conférence Internationale Tournesol; 2000

International Sunflower Association

The objective of this work was to investigate and model the distribution of secondary roots along the taproot and its relationship with the position of the cotyledons in the aerial part of the plant. Root systems of seedlings cultivated in field conditions in three different sowing dates and root systems of seedlings grown in nutritive solution were observed. The distances between individual secondary roots were measured and the distribution of the branches along the taproot and the relationship between this distribution and the position of the cotyledons in the hypocotile were also recorded. The distribution of branches was analysed using Markov chains. The secondary roots inserted in the top 150 mm of the taproot appear in four vertical planes. The secondary roots inserted in the rest of the taproot appear only on both sides of the plane in which the cotyledons are inserted in the hypocotile. In this zone, the minimum distance between branches was 1 mm. The data of the three sowing dates in field conditions were well described using first order Markov chains and graphic simulations calculated with these parameters gave realistic views of root systems. Markov chains are then a valid tool for modelling the root branching of sunflower seedlings.