The Topology and Geometry of Plant Root Systems: Influence of Watering Rate on Root System Topology in Trifolium pratense

The description of branching structures is discussed and a link-based system is described. This system can be used to distinguish topologically distinct networks and the growth rules which give rise to distinct topologies are outlined. Classifications of links within networks are also described. These methods are applied to the analysis of red clover Trifolium pratense root systems grown at different watering rates, and reveal that at intermediate supply rates a random branching model is satisfied, but that at extreme rates, departures from randomness are found. The implications of this are discussed in terms of growth rules, the space-filling properties of root systems, and their transport efficiency. It is shown that these root systems increase in transport efficiency as water supply increases.