Root Development and Abiotic Stress Adaptation - Abiotic Stress: Plant Responses and Applications in Agriculture - page 147

stress conditions [124], these same authors found that overexpression of MYB96 promotes
resistance to drought and reduced lateral root density.
4.2. Regulation of root system architecture by nutrients
In soil nutrients such as phosphorus (P), nitrogen (N), potassium (K) and iron (Fe), are
distributed in a heterogenous patching pattern. As soon as the PR emerges from the seed, it
has to grow. As growth goes on, de novo LR are formed to generate the particular RS mor‐
phology and architecture. These nutrients alter root patterning through particular signal
transduction pathways. Thus, during their life plants change their PEDP in order to increase
exponentially the root-soil interaction area and find the nutrient-rich regions [5, 125-129]. The
changes in Arabidopsis root system are specific for each nutrient. P, N and K starvation
dramatically alter primary root length (Figure 2).
Figure 2. Changes in root system architecture of Arabidopsis seedlings when growth on media depleted of phospho‐
rous (P), nitrogen (N), potassium (P) and iron (Fe).
4.2.1. Phosphate starvation
Root system in boot monocotyledonous and dicotyledonous plants, present a set of develop‐
mental modifications that tend to increase the exploratory capacity of the plant [130]. When
Arabidopsis growth under limiting P conditions their RSA changes dramatically such as
reduction in primary root length, increased formation of LRs and greater formation of root
hairs [126, 128]. On optimal P conditions the newly formed root cells are added by the mitotic
activity of primary meristem. These cells then get away from the meristem and increase their
length, and the elongation process ends when the cells start to differentiate. When plants are
P starved, cell division in the primary root meristems gradually reduces and the cells start to