Under compacted conditions shorter and wider cortical cells are produced. The root cap both protects the meristem and determines the interaction between the soil and the root at the time of root growth indicating that the pressure on a root cap decreases root growth in a compacted soil. One of the reasons is that root cap reduces the friction coefficient between the root and soil at the time of root growth (Amzallag, 1999). This may also be the reason for higher soil resistance in a dry soil compared with a wet soil (Bengough et al., 2006). The meristematic parts in root tips may determine the root architecture and, hence the volume of soil available to the plant root for uptake, and also for the production of plant signals (Harrison, 2005). This part of the root is very much affected in a compacted soil